Oxynitride semiconductor thin film

Abstract

The purpose of the present invention is to provide an oxide semiconductor thin film, which has relatively high carrier mobility and is suitable as a channel layer material for a TFT, from an oxynitride crystalline thin film. According to the present invention, a crystalline oxynitride semiconductor thin film is obtained by annealing an amorphous oxynitride semiconductor thin film containing In, O, and N or an amorphous oxynitride semiconductor thin film containing In, O, N, and an additional element M, where M is one or more elements selected from among Zn, Ga, Ti, Si, Ge, Sn, W, Mg, Al, Y and rare earth elements, at a heating temperature of 200 C. or more for a heating time of 1 minute to 120 minutes.

Claims

1. An oxynitride semiconductor thin film comprising: a crystalline oxynitride semiconductor comprising In as a main component, O, N, and added element M, where M is one or more element selected from among Zn, Ga, Ti, Si, Ge, Sn, W, Mg, Al, Y, and rare-earth elements, the amount of added element M included in terms of atomic ratio M/(In+M) is greater than 0 but no greater than 0.20; a crystal structure of In.sub.2O.sub.3 phase of Bixbyite structure with N atoms solid-soluted in the In.sub.2O.sub.3 phase, the amount of N included in the crystalline oxynitride semiconductor being 310.sup.20 atoms/cm.sup.3 or more but less than 110.sup.22 atoms/cm.sup.3, and a carrier density of 110.sup.17 cm.sup.3 or less, and a carrier mobility of 5 cm.sup.2/Vsec or more.

2. The oxynitride semiconductor thin film according to claim 1, wherein the carrier mobility is 15 cm.sup.2/Vsec or greater.

3. The oxynitride semiconductor thin film according to claim 1, wherein the carrier mobility is 25 cm.sup.2/Vsec or greater.

4. The oxynitride semiconductor thin film according to claim 1, wherein the film thickness is 15 nm to 200 nm.

5. The oxynitride semiconductor thin film according to claim 1, wherein the film thickness is 40 nm to 100 nm.

6. A manufacturing method for the oxynitride semiconductor thin film comprising a step of: performing an annealing process at a heating temperature of 200 C. or greater, and heating time of 1 minute to 120 minutes on an amorphous oxynitride semiconductor thin film that includes In as a main component, O, N, and added element M, where M is one or more element selected from among Zn, Ga, Ti, Si, Ge, Sn, W, Mg, Al, Y, and rare-earth elements to obtain the oxynitride semiconductor thin film according to claim 1.

7. A thin-film transistor that is a thin film transistor comprising a source electrode, a drain electrode, a gate electrode, a channel layer, and a gate insulation film, wherein the channel layer comprises the oxynitride semiconductor thin film of claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a cross-sectional schematic view of a TFT element of the present invention.

MODES FOR CARRYING OUT INVENTION

(2) The inventors diligently studied alternative materials for an oxide semiconductor thin film. More specifically, many experiments were performed for forming a crystalline oxynitride semiconductor thin film by performing an annealing process on an oxynitride semiconductor thin film that was obtained by a sputtering method and having In as the main component. When doing this, detailed study was performed for conditions for achieving a crystalline oxynitride semiconductor thin film having high carrier mobility and suppressed carrier density. As a result, the inventors learned that a crystalline oxynitride semiconductor thin film that is obtained by performing an annealing process under specified conditions on an amorphous oxynitride semiconductor thin film to which In, O and N, or specified additional element has been added has a low carrier density of 110.sup.17 cm.sup.3 while having a high carrier density of 5 cm.sup.2/Vsec, and can be suitably used as channel-layer material for a thin-film transistor (TFT). The present invention was achieved based on this knowledge.

(3) In the following, the oxynitride semiconductor thin film and the thin-film transistor (TFT) that uses this oxynitride semiconductor thin film as a channel-layer material will be explained in detail.

(4) 1. Oxynitride Semiconductor Thin Film

(5) (1) Composition

(6) The oxynitride semiconductor thin film of the present invention comprises an oxynitride semiconductor thin film that includes In, O, and N, and an addition element(s) in addition to these.

(7) Typically, a crystalline oxide semiconductor thin film having In as the main component is such that oxygen deficiency occurs easily, and since this oxygen deficiency is the main carrier, there is a tendency for the carrier density to become high. However, in the present invention, an oxynitride semiconductor thin film is formed by adding N, and the holes that are generated by N behaving as an acceptor neutralizes the electrons that become carriers that occurred due to oxygen deficiency, so it becomes possible to suppress the carrier density.

(8) The amount of N included in the oxynitride semiconductor thin film is 310.sup.20 atoms/cm.sup.3 or greater but less than 110.sup.22 atoms/cm.sup.3, and preferably is no less than 510.sup.20 atoms/cm.sup.3 and no greater than 810.sup.21 atoms/cm.sup.3, and more preferably is no less than 810.sup.20 atoms/cm.sup.3 and no greater than 610.sup.21 atoms/cm.sup.3. When the amount of N included is less than 310.sup.20 atoms/cm.sup.3, it is not possible to sufficiently obtain the effect above. On the other hand, even when the amount of N included is 110.sup.22 atoms/cm.sup.3 or greater, more effect cannot be expected. Moreover, the crystallization temperature becomes too high, so even though an annealing process is performed at a temperature of 400 C. or greater, it becomes difficult to obtain a crystalline oxide semiconductor thin film.

(9) The oxynitride semiconductor thin film of the present invention, in addition to In, O, and N, can also include an additional element(s) whose function becomes dominant in keeping the carrier mobility from decreasing, and suppressing the occurrence of oxygen deficiency without the carrier density as a carrier source becoming higher than necessary. More specifically, it is possible to include one or more element selected from among Zn, Ga, Ti, Si (silicon), Ge (germanium), Sn, W, Mg (magnesium), Al (aluminum), Y (yttrium), and rare-earth elements represented by La (lanthanum) and Sc (scandium). In the case of rare-earth elements, it is difficult for trivalent elements represented by La, Sc or the like to become a factor for ionized impurity scattering, so can be suitably used as additional elements.

(10) When including additional elements M, the amount included, in terms of the atomic ratio M/(In+M), is preferably greater than 0 but not greater than 0.20, and more preferably is no less than 0.05 and no greater than 0.15, and even more preferably is no less than 0.08 and no greater than 0.12. When the amount of M included in terms of M/(In+M) is greater than 0.20, the ratio of In included in the oxynitride semiconductor thin film decreases, and it is not possible to make the carrier mobility 5 cm.sup.2/Vsec or greater. However, when Zn is used as the additional element M, it becomes easy for the crystal structure to become a hexagonal crystal structure, so the amount included is preferably 0.10 or less, and more preferably 0.05 or less.

(11) (2) Crystal Structure

(12) In the oxynitride semiconductor thin film of the present invention, as long as the structure is crystalline, the crystal structure is not particularly limited, however, preferably the structure comprises the In.sub.2O.sub.3 phase of Bixbyite structure, and the N atoms are solid-soluted in the In.sub.2O.sub.3 phase. Particularly, it is preferred that all or part of the N atoms are substituted for the oxygen sites in the In.sub.2O.sub.3 phase, or that all or part of the N atoms penetrate in between the In.sub.2O.sub.3 crystal lattice. In the In.sub.2O.sub.3 phase of Bixbyite structure, InO.sub.6 octahedron structure comprising In and O is formed, and due to the sharing of edges of adjacent InO.sub.6 octahedron structures, the distance between InIn becomes short, and the overlap of orbiting carrier electrons becomes large. Therefore, by making the oxynitride semiconductor thin film comprise this kind of crystal structure, it is possible to improve the carrier mobility.

(13) Here, comprising In.sub.2O.sub.3 phase Bixbyite structure not only includes the case of comprising only In.sub.2O.sub.3 phase Bixbyite structure, but also includes the case of a heterogeneous phase existing in addition to the Bixbyite structure In.sub.2O.sub.3 phase within a range such that the crystal structure does not break apart. The crystal structure of the oxynitride semiconductor thin film can be identified by x-ray diffraction measurement.

(14) (3) Film Thickness

(15) The film thickness of the oxynitride semiconductor thin film of the present invention is preferably regulated to be within the range 15 nm to 200 nm, and more preferably 30 nm to 150 nm, and even more preferably 40 nm to 100 nm. The film thickness can be measured by a profilometer.

(16) Typically, a semiconductor thin film is often formed on a glass substrate. In other words, a crystalline oxynitride semiconductor thin film is formed on an amorphous substrate. Therefore, in the case of the oxynitride semiconductor thin film of the present invention, when the film thickness is less than 15 nm, it is possible that due to the effect of the substrate, the precursor oxynitride amorphous thin film will not crystallize even though an annealing process is performed at a high temperature of 400 C. Even when presuming that it is possible to crystallize this oxynitride amorphous thin film, it is difficult to make the crystallinity sufficient. The effect that an amorphous substrate has on the crystallinity of an oxynitride semiconductor can be further reduced by making the film thickness 30 nm or greater, however, it is possible to stably eliminate that effect by making the film thickness 40 nm or greater. However, when taking cost into consideration, the upper limit value for the film thickness is preferably 200 nm or less, and more preferably 150 nm or less, and even more preferably 100 nm or less.

(17) Moreover, when an oxynitride semiconductor thin film is formed on a glass substrate by controlling the film thickness to be in close to 100 nm, it is possible to expect an improvement in the transmittance of blue light due to optical interference. Therefore, when applying the oxynitride semiconductor thin film of the present invention to a transparent TFT, preferably the film thickness is adjusted to be close to 100 nm.

(18) (4) Characteristics

(19) The oxynitride semiconductor thin film of the present invention is crystalline, and comprises an oxynitride including In, O, and N, or including In, O, N, and additional elements M. Therefore, the TFT elements to which the oxynitride semiconductor thin film of the present invention is applied has high stability against external factors such as heat, and does not have defects such as the occurrence of the light negative bias degradation phenomenon.

(20) In the oxynitride semiconductor thin film of the present invention, it is necessary to perform control so that the carrier density is 110.sup.17 cm.sup.3 or less, and preferably 810.sup.16 cm.sup.3, and more preferably 510.sup.16 cm.sup.3 or less. When the carrier density is greater than 110.sup.17 cm.sup.3, it becomes difficult to achieve a high ON/OFF ratio, so it is not possible to apply this material as a TFT channel-layer material that requires high-speed driving. Here, the ON/OFF ratio means the ratio of the current value between the conducting state and the blocked state.

(21) On the other hand, it is necessary to perform control so that the carrier mobility is 5 cm.sup.2/Vsec or greater. When the carrier mobility is less than 5 cm.sup.2/Vsec, it is difficult to maintain the high pixel control performance of a TFT. Particularly, taking into consideration application in a high-definition liquid-crystal panel TFT, it is necessary that the carrier mobility preferably be 15 cm.sup.2/Vsec or greater, and more preferably 25 cm.sup.2/Vsec or greater.

(22) The carrier density and carrier mobility can be found by measuring the Hall effect of an oxynitride semiconductor thin film using a Hall effect measuring device.

(23) The oxynitride semiconductor thin film of the present invention is controlled in this way so that the carrier density and carrier mobility are within the ranges above, so not only is it possible to use this thin film as a channel layer material that requires a carrier density that is 2 to 4 digits lower than an oxide transparent conductive film, but it is also possible to maintain the high pixel control performance of a TFT due to the high carrier mobility.

(24) Moreover, the oxynitride semiconductor thin film of the present invention is such that by using wet etching or dry etching, it is possible to simplify the fine processing required for use in a TFT or the like. For example, in the case of manufacturing the oxynitride semiconductor thin film of the present invention by first forming an amorphous film, and then crystallizing the oxynitride semiconductor thin film by performing an annealing process at the crystallization temperature or higher, it is possible to perform processing by wet etching that uses a weak acid after forming the amorphous film. In this case, as long as the acid is a weak acid, the acid is not particularly limited, however, preferably the weak acid has oxalic acid as the main component. More specifically, it is possible to use a transparent conductive film etching liquid (ITO-06N) manufactured by Kanto Chemical Co., Ltd. or like. On the other hand, in the case of dry etching, it is possible to perform processing using a suitable etching gas on the oxynitride semiconductor thin film.

(25) 2. Manufacturing Method for an Oxynitride Semiconductor Thin Film

(26) As was described above, the oxynitride semiconductor thin film of the present invention must be crystalline. As methods for obtaining this kind of crystalline thin film, there is a method in which a film is formed with the substrate temperature during film formation being the crystallization temperature or greater, and there is a method in which after an amorphous film is formed at a temperature less than the crystallization temperature, crystallization is performed by annealing or the like. In the present invention, it is possible to use either method, however, by performing an annealing process on an amorphous film, it is possible to efficiently eliminate oxygen deficiency, so from the aspect of obtaining a low carrier density, employing the latter method is advantageous. Therefore, in the following, the manufacturing method for manufacturing the oxynitride semiconductor thin film of the present invention will be explained for the case of using the latter method.

(27) (1) Film Formation Process

(28) (Substrate)

(29) As the substrate on which the oxynitride semiconductor thin film of the present invention will be formed, it is possible to use a glass substrate, or a substrate for a semiconductor device such as a Si (silicon) substrate or the like. Moreover, even when the substrate is a substrate other than these, as long as the substrate is able to withstand the temperature during the annealing process during film formation, it is possible to use a resin board or resin film.

(30) (Raw Material)

(31) As the raw material, it is possible to use sintered oxide or sintered oxynitride. However, when using a sintered oxide for the raw material, it is necessary that N be included in the atmosphere during film formation, which will be explained later.

(32) The composition ratios of the metal elements of the sintered oxide or sintered oxynitride raw material can be suitably set according to the film formation conditions, however, normally, it is preferred that the composition ratios be the same as the composition ratios of the metal elements of the target oxynitride semiconductor thin film.

(33) (Film Formation Method)

(34) The method for forming the oxynitride semiconductor thin film of the present invention is not particularly limited, and it is possible to use a sputtering method, ion-plating method, epitaxial growth method or the like. Of these, using a direct-current sputtering method that is not affected much by heat during film formation, and that is capable of high-speed film formation is preferred.

(35) For example, when forming an oxynitride semiconductor thin film by a sputtering method, the pressure inside the chamber of the sputtering device is set to 210.sup.4 Pa by vacuum evacuation, after which, a gas mixture of Ar (argon), O.sub.2 and N.sub.2 is introduced, and together with adjusting the gas pressure to 0.1 Pa to 1 Pa, and preferably 0.2 Pa to 0.8 Pa, and more preferably 0.2 Pa to 0.5 Pa, the distance between the target and substrate is adjusted to 10 mm to 100 mm, and preferably 40 mm to 70 mm. Next, direct-current plasma is generated by applying direct-current electric power so that the direct-current electric power with respect to the target surface area, or in other words the direct-current electric power density is within the range 1 W/cm.sup.2 to 3 W/cm.sup.2, and after performing pre-sputtering for 5 minutes to 30 minutes, the substrate position is corrected as necessary and sputtering is performed under the same conditions.

(36) The substrate temperature during film formation is preferably 200 C. or less when the film thickness is within the range 15 nm to 70 nm, and is preferably 100 C. or less when the film thickness is within the range 70 nm to 200 nm. In either case, the temperature is more preferably within the range from room temperature to 100 C.

(37) As the sputtering gas, when sintered oxynitride is used as the target, a gas mixture comprising an inert gas and O.sub.2 is used, and preferably a gas mixture comprising Ar and O.sub.2 is used. On the other hand, when sintered oxide is used as the target, a gas mixture comprising an inert gas, O.sub.2 and N.sub.2 is used, and preferably a gas mixture comprising Ar, O.sub.2, and N.sub.2 is used.

(38) The O.sub.2 concentration in the sputtering gas must be suitably adjusted according to the sputtering conditions and particularly according to the direct-current electric power density. For example, when performing sputtering by controlling the direct-current electric power to be within the range 1 W/cm.sup.2 to 3 W/cm.sup.2, the O.sub.2 concentration is preferably 0.1% by volume to 10% by volume, and more preferably 0.5% by volume to 8.0% by volume, and even more preferably 1.0% by volume to 5.0% by volume. When the O.sub.2 concentration is less the 0.1% by volume, oxygen deficiency occurs, and there is a possibility that the carrier density will increase. On the other hand, when the O.sub.2 concentration is greater than 10% by volume, the speed of film formation greatly drops.

(39) As the sputtering gas, when a gas mixture comprising an inert gas, O.sub.2, and N.sub.2 is used, the N.sub.2 concentration in the sputtering gas must similarly be suitably adjusted according to the sputtering conditions such as the direct-current electric power. For example, when performing sputtering by controlling the direct-current electric power to be within the range above, the N.sub.2 concentration is preferably controlled to be no less than 0.4% by volume but less than 6.0% by volume, and preferably no less than 0.5% by volume and no greater than 5.7% by volume, and even more preferably no less than 1.0% by volume and no greater than 5.0% by volume. When the N.sub.2 concentration is less than 0.4% by volume, it may not be possible to obtain an oxynitride semiconductor thin film in which a sufficient amount of N is solid-soluted. On the other hand, when the N.sub.2 concentration is 6.0% by volume or greater, not only does the speed of film formation greatly decrease, but the crystallization temperature increases due to the increased amount of N that is included in the oxynitride semiconductor thin film, and thus it becomes difficult to obtain a crystalline oxynitride semiconductor thin film even when an annealing process is performed at 400 C. or greater.

(40) (2) Annealing Process

(41) As was described above, in the manufacturing method for an oxynitride semiconductor thin film of the present invention, after forming an amorphous oxynitride semiconductor thin film, it is necessary to crystallize the oxynitride semiconductor thin film by performing an annealing process.

(42) The heating temperature during the annealing process must be 200 C. or greater, and preferably 250 C. or greater, and even more preferably 300 C. or greater. When the heating temperature is less than 200 C., it is not possible to sufficiently crystallize the oxynitride semiconductor thin film. The upper limit for the heating temperature is not particularly limited, however, in consideration of productivity, preferably the temperature is 400 C. or less.

(43) The processing time is taken to be 1 minute to 120 minutes, and preferably 5 minutes to 60 minutes. When the processing time is less than 1 minute, it is not possible to sufficiently crystallize the oxynitride semiconductor thin film that is obtained. On the other hand, when the processing time is greater than 120 minutes, no further effect can be expected, so productivity worsens.

(44) The atmosphere for the annealing process is not limited, however, when the object is to crystallize that film as well as reduce the carrier density, preferably the atmosphere includes O.sub.2, and more preferably the O.sub.2 concentration is 20% by volume or greater, and even more preferably processing is performed in an air atmosphere.

(45) Preferably, these conditions are suitably adjusted according to the performance of the annealing furnace that is used for the annealing process.

(46) JP 2010-251604 (A) discloses technology in which after a film such as a channel layer is formed by a non-heating sputtering method as described above, excess defects in the amorphous film are reduced while maintaining an amorphous nature by performing an annealing process in an air atmosphere at 150 C. to 300 C. for 10 minutes to 120 minutes. Moreover, in the examples of JP 2010-251604 (A), an annealing process is performed in an air atmosphere at 150 C. for 30 minutes on an InWZnO film (W=1 wt % to 10 wt %) that was formed with no heating. In other words, the technology that is disclosed in JP 2010-251604 (A) is technology in which by adding a suitable amount of an element(s) that can be solid-soluted in the In.sub.2O.sub.3 phase and make it possible to increase the crystallization process, makes it possible to maintain the amorphous nature of the oxynitride semiconductor thin film in an annealing process that is performed in the temperature range above, and this point differs from the present invention.

(47) Moreover, in JP 2009-275236 (A), an amorphous oxynitride semiconductor thin film that was obtained by a sputtering method or a vapor deposition method is converted to a crystalline oxynitride semiconductor thin film having a hexagonal crystal structure and having a crystal grain size that is about the same as the film thickness by performing an annealing process at a temperature of 150 C. to 450 C. In this way, the oxynitride semiconductor thin film disclosed in JP 2009-275236 (A) basically has a hexagonal crystal structure, so the aspects of being easy for oxygen deficiency to occur in the formation process of a thin film having a complex crystal structure, and having a small effect on suppressing the carrier density differ from the present invention.

(48) 3. TFT Element

(49) A feature of the thin-film transistor (TFT) of the present invention is that the oxynitride semiconductor thin film of the present invention is applied as channel-layer material. The structure of the TFT is not limited, however, an example of a TFT element that is constructed as illustrated in FIG. 1 is possible.

(50) The TFT element that is illustrated in FIG. 1 is constructed by the oxynitride semiconductor thin film of the present invention, and an Au/Ti layered electrode formed on a SiO.sub.2/Si substrate that is formed on the surface of a SiO.sub.2 film by thermal oxidation. In this construction, the gate electrode 1 comprises a Si substrate, the gate insulation layer 2 comprises a SiO.sub.2 film, the channel layer 3 comprises the oxynitride semiconductor thin film of the present invention, and the source electrode 4 and the drain electrode 5 comprise an Au/Ti layered electrode.

(51) In the TFT element illustrated in FIG. 1, a SiO.sub.2/Si substrate was used, however, the substrate is not limited to this, and it is also possible to use a conventional substrate that is used as the substrate for an electronic device that includes a thin-film transistor. For example, in addition to a SiO.sub.2/Si substrate or Si substrate, it is possible to use a glass substrate such as a non-alkali glass substrate, quartz glass substrate and the like. Moreover, it is also possible to use a non-transparent heat-resistant polymeric film substrate such as various metal substrates, plastic substrate, polyimide substrate and the like.

(52) The gate electrode 1, in the TFT element in FIG. 1 comprises a Si substrate, however the gate electrode 1 is not limited to this. For example, it is also possible to use a metal thin film of Mo (molybdenum), Al, Ta (tantalum), Ti, Au (gold), Pt (platinum) and the like, an electrically conductive oxide, nitride or oxynitride thin films of these metals, or various thin films of electrically conductive polymeric materials. In the case of a transparent TFT, it is possible to use a transparent electrically conductive film such as an indium tin oxide (ITO) thin film. Furthermore, it is also possible to use an oxynitride semiconductor thin film having the same metal element composition as the oxynitride semiconductor thin film of the present invention as the gate electrode 1. In the case of using any of these materials, the specific resistance of the gate electrode 1 is preferably in the range 110.sup.6 .Math.cm to 110.sup.1 .Math.cm, and more preferably in the range 110.sup.6 .Math.cm to 110.sup.3 .Math.cm.

(53) For the gate insulation layer 2, it is possible to use a known material such as a metal oxide thin film such as a thin film of SiO.sub.2, Y.sub.2O.sub.3, Ta.sub.2O.sub.5, Hf oxide and the like, a metal nitride thin film such as a SiNx thin film and the like, or an insulating polymeric material such as a polyimide. The specific resistance of the gate insulation layer 2 is preferably in the range 110.sup.6 .Math.cm to 110.sup.15 .Math.cm, and more preferably in the range 110.sup.10 .Math.cm to 110.sup.15 .Math.cm.

(54) The specific resistance of the channel layer 3 is not particularly limited, however, preferably is controlled to be 10.sup.1 .Math.cm to 10.sup.6 .Math.cm, and more preferably is controlled to be 1 .Math.cm to 10.sup.3 .Math.cm. In the oxynitride semiconductor thin film of the present invention, it is possible to adjust the amount of oxygen deficiency that occurs by selecting the film formation conditions for the sputtering method or ion plating method, and conditions for the crystallization annealing process, so it is possible to comparatively easily control the specific resistance.

(55) As the source electrode 4 and the drain electrode 5, as in the case of the gate electrode 1, it is possible to use a metal thin film of Mo, Al, Ta, Ti, Au, Pt and the like, an electrically conductive oxide, nitride or oxynitride thin films of these metals, or various thin films of electrically conductive polymeric materials. In the case of a transparent TFT, it is possible to use a transparent electrically conductive film such as an ITO film. Furthermore, it is also possible to use a layered film of these thin films. Good electrical conductivity is desired for the source electrode 4 and drain electrode 5. More specifically, the specific resistance of the source electrode 4 and drain electrode 5 is preferably in the range 10.sup.6 .Math.cm to 10.sup.1 .Math.cm, and more preferably in the range 10.sup.6 .Math.cm to 10.sup.3 .Math.cm.

(56) 4. Manufacturing Method for a TFT Element

(57) The manufacturing method for a TFT element of the present invention will be explained by giving an example of a method for performing an annealing process after low-temperature film formation when forming an oxynitride semiconductor thin film.

(58) First, a SiO.sub.2/Si substrate is formed by forming a SiO.sub.2 film on the surface of a high-doped n-type Si wafer substrate by thermal oxidation. With this substrate maintained at 100 C. or less, an amorphous oxynitride semiconductor thin film having a specified film thickness is formed on the SiO.sub.2 film by a direct-current magnetron sputtering method. The film formation conditions when doing this are the same as the conditions explained in 2. Manufacturing Method for an Oxynitride Semiconductor Thin Film, so an explanation here is omitted. Moreover, when forming this amorphous thin film, it is possible to form an oxynitride semiconductor thin film having a desired channel length and/or channel width by performing film formation after masking, or by performing etching using photolithography or the like after forming the amorphous thin film.

(59) Next, a crystalline oxynitride semiconductor thin film is formed by performing an annealing process on this oxynitride semiconductor thin film. The conditions for this annealing process are also the same as the conditions explained in 2. Manufacturing Method for an Oxynitride Semiconductor Thin Film, so an explanation here will be omitted.

(60) After that, the TFT element of the present invention can be obtained by performing masking on the obtained crystalline oxynitride semiconductor thin film (channel layer), and forming the source electrode and drain electrode by sequentially layering a 5 nm thick Ti film and a 100 nm thick Au film. Formation of the source electrode and the drain electrode, is the same as formation of the channel layer, and can be performed by employing a method of performing etching using photolithography or the like after formation of the Ti thin film and Au thin film.

EXAMPLES

(61) In the following, the present invention will be explained in further detail by using some examples, however the present invention is not limited by these examples.

Example 1

(62) An oxynitride semiconductor thin film was formed by using an In.sub.2O.sub.3 sintered oxide compact comprising only the In.sub.2O.sub.3 phase as a sputtering target.

(63) First, this sputtering target was attached to a cathode for a non-magnetic target of a direct-current magnetron sputtering device (SPK503, manufactured by Tokki Corp.) having no arcing restraint function. Moreover, a non-alkaline glass substrate (EAGLE XG, manufactured by Corning Inc.) was used for the substrate. The distance between the target and substrate was fixed at 60 mm, and after performing vacuum evacuation to 210.sup.4 Pa or less, a gas mixture comprising Ar, O.sub.2 and N.sub.2 was mixed in so that the O.sub.2 concentration was 1.5% by volume, and the N.sub.2 concentration was 1.5% by volume, and the gas pressure was adjusted to 0.6 Pa.

(64) After that, film formation was performed by applying direct-current electric power of 300 W (1.64 W/cm.sup.2) to generate direct-current plasma. More specifically, after performing pre-sputtering for 10 minutes, the substrate was placed at a stationary position facing the sputtering target, and sputtering was performed without heating the substrate. As a result, a 50 nm thick oxynitride semiconductor thin film was formed. The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry using an ICP atomic emission spectrometry device (SPS3520UV, manufactured by Hitachi High-Tech Science Corporation), and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction using an x-ray diffraction device (X'PertPRO MPD, manufactured by Panalytical), and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(65) Next, an annealing process was performed on this oxynitride semiconductor thin film in an air atmosphere for 30 minutes at 300 C. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed using a secondary ion mass spectrometry device (PHI ADEPT1010, manufactured by ULVAC-PHI, Inc.), and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 810.sup.20 atoms/cm.sup.3. The secondary ion spectrometry measurement was performed using a reference sample in which N ions were implanted in In.sub.2O.sub.3 thin film. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(66) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer (Alpha-Step IQ, manufactured by KLA-Tencor Corporation), and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device (ResiTest 8400, manufactured by TOYO Corporation), and as a result, it was confirmed that the carrier density was 510.sup.16 cm.sup.3, and the carrier mobility was 29 cm.sup.2/Vsec.

Example 2

(67) Except for performing the annealing process in an air atmosphere for 30 minutes at 400 C., the oxynitride semiconductor thin film was obtained in the same was as in Example 1.

(68) The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed using a secondary ion mass spectrometry device, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 810.sup.20 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(69) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 210.sup.16 cm.sup.3, and the carrier mobility was 30 cm.sup.2/Vsec.

Example 3

(70) Except for the O.sub.2 concentration in the sputtering gas being 1.4% by volume and the N.sub.2 concentration being 5.7% by volume, the oxynitride semiconductor thin film was obtained in the same was as in Example 1.

(71) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(72) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 1. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed using a secondary ion mass spectrometry device, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 510.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(73) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 810.sup.15 cm.sup.3, and the carrier mobility was 27 cm.sup.2/Vsec.

Example 4

(74) Except for the O.sub.2 concentration in the sputtering gas being 1.4% by volume and the N.sub.2 concentration being 5.7% by volume, the oxynitride semiconductor thin film was obtained in the same was as in Example 1.

(75) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(76) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 510.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(77) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 410.sup.15 cm.sup.3, and the carrier mobility was 30 cm.sup.2/Vsec.

Example 5

(78) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(79) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(80) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 1. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 110.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(81) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 710.sup.14 cm.sup.3, and the carrier mobility was 28 cm.sup.2/Vsec.

Example 6

(82) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(83) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(84) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 110.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(85) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 410.sup.14 cm.sup.3, and the carrier mobility was 30 cm.sup.2/Vsec.

Example 7

(86) Except for the O.sub.2 concentration in the sputtering gas being 1.5% by volume and the N.sub.2 concentration being 0.5% by volume, the oxynitride semiconductor thin film was obtained in the same was as in Example 5.

(87) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(88) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 410.sup.20 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(89) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 110.sup.15 cm.sup.3, and the carrier mobility was 28 cm.sup.2/Vsec.

Example 8

(90) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(91) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(92) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2 except that the time of heat treatment was 120 minutes. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 110.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(93) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 210.sup.14 cm.sup.3, and the carrier mobility was 20 cm.sup.2/Vsec.

Example 9

(94) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(95) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(96) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2 except that the time of heat treatment was 60 minutes. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 110.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(97) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 310.sup.14 cm.sup.3, and the carrier mobility was 27 cm.sup.2/Vsec.

Example 10

(98) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(99) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(100) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2 except that the time of heat treatment was 5 minutes. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 110.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(101) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 610.sup.14 cm.sup.3, and the carrier mobility was 30 cm.sup.2/Vsec.

Example 11

(102) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(103) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(104) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2 except that the time of heat treatment was 1 minute. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 110.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(105) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 110.sup.15 cm.sup.3, and the carrier mobility was 30 cm.sup.2/Vsec.

Example 12

(106) Except for the O.sub.2 concentration in the sputtering gas being 1.4% by volume and the N.sub.2 concentration being 5.7% by volume, the oxynitride semiconductor thin film was obtained in the same was as in Example 5.

(107) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(108) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 1. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 810.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(109) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 610.sup.14 cm.sup.3, and the carrier mobility was 26 cm.sup.2/Vsec.

Example 13

(110) Except for the O.sub.2 concentration in the sputtering gas being 1.4% by volume and the N.sub.2 concentration being 5.7% by volume, the oxynitride semiconductor thin film was obtained in the same was as in Example 5.

(111) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(112) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 810.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(113) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 310.sup.14 cm.sup.3, and the carrier mobility was 28 cm.sup.2/Vsec.

Example 14

(114) Except for the film thickness being 15 nm, oxynitride semiconductor thin film was obtained in the same was as in Example 5.

(115) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(116) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 310.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(117) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 15 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 610.sup.14 cm.sup.3, and the carrier mobility was 26 cm.sup.2/Vsec.

Example 15

(118) Except for the film thickness being 200 nm, oxynitride semiconductor thin film was obtained in the same was as in Example 5.

(119) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(120) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 810.sup.20 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(121) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 200 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 310.sup.14 cm.sup.3, and the carrier mobility was 29 cm.sup.2/Vsec.

Example 16

(122) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga+Y) of 0.10, and includes Y at an atomic ratio Y/(In+Ga+Y) of 0.05 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(123) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(124) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 410.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(125) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 310.sup.14 cm.sup.3, and the carrier mobility was 27 cm.sup.2/Vsec.

Example 17

(126) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga+La) of 0.10, and includes La at an atomic ratio La/(In+Ga+La) of 0.05 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(127) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(128) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 210.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(129) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 210.sup.14 cm.sup.3, and the carrier mobility was 26 cm.sup.2/Vsec.

Example 18

(130) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga) of 0.05 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(131) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(132) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 810.sup.20 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(133) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 710.sup.14 cm.sup.3, and the carrier mobility was 29 cm.sup.2/Vsec.

Example 19

(134) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga) of 0.08 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(135) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(136) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 910.sup.20 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(137) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 510.sup.14 cm.sup.3, and the carrier mobility was 29 cm.sup.2/Vsec.

Example 20

(138) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga) of 0.12 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(139) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(140) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 210.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(141) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 310.sup.14 cm.sup.3, and the carrier mobility was 27 cm.sup.2/Vsec.

Example 21

(142) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga) of 0.15 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(143) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(144) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 310.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(145) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 210.sup.14 cm.sup.3, and the carrier mobility was 26 cm.sup.2/Vsec.

Example 22

(146) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga) of 0.20 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(147) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(148) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 410.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(149) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 110.sup.14 cm.sup.3, and the carrier mobility was 25 cm.sup.2/Vsec.

Example 23

(150) Except for using a sintered oxide compact that includes Zn in the In.sub.2O.sub.3 at an atomic ratio of Zn/(In+Zn) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(151) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(152) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 910.sup.20 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(153) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 210.sup.15 cm.sup.3, and the carrier mobility was 12 cm.sup.2/Vsec.

Example 24

(154) Except for using a sintered oxide compact that includes Ti in the In.sub.2O.sub.3 at an atomic ratio of Ti/(In+Ti) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(155) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(156) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 210.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(157) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 610.sup.14 cm.sup.3, and the carrier mobility was 8 cm.sup.2/Vsec.

Example 25

(158) Except for using a sintered oxide compact that includes W in the In.sub.2O.sub.3 at an atomic ratio of W/(In+W) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(159) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(160) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 910.sup.20 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(161) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 710.sup.14 cm.sup.3, and the carrier mobility was 10 cm.sup.2/Vsec.

Example 26

(162) Except for using a sintered oxide compact that includes Mg in the In.sub.2O.sub.3 at an atomic ratio of Mg/(In+Mg) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(163) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(164) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 910.sup.20 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(165) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 110.sup.15 cm.sup.3, and the carrier mobility was 8 cm.sup.2/Vsec.

Example 27

(166) Except for using a sintered oxide compact that includes Al in the In.sub.2O.sub.3 at an atomic ratio of Al/(In+Al) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(167) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(168) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 310.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(169) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 810.sup.14 cm.sup.3, and the carrier mobility was 22 cm.sup.2/Vsec.

Example 28

(170) Except for using a sintered oxide compact that includes Y in the In.sub.2O.sub.3 at an atomic ratio of Y/(In+Y) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(171) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(172) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 310.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(173) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 310.sup.15 cm.sup.3, and the carrier mobility was 20 cm.sup.2/Vsec.

Example 29

(174) Except for using a sintered oxide compact that includes La in the In.sub.2O.sub.3 at an atomic ratio of La/(In+La) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(175) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(176) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 210.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(177) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 110.sup.15 cm.sup.3, and the carrier mobility was 18 cm.sup.2/Vsec.

Example 30

(178) Except for using a sintered oxide compact that includes Sc in the In.sub.2O.sub.3 at an atomic ratio of Sc/(In+Sc) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(179) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(180) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 210.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(181) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 610.sup.15 cm.sup.3, and the carrier mobility was 17 cm.sup.2/Vsec.

Example 31

(182) Except for using a sintered oxide compact that includes Si in the In.sub.2O.sub.3 at an atomic ratio of Si/(In+Si) of 0.05 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(183) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(184) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 410.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(185) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 810.sup.16 cm.sup.3, and the carrier mobility was 29 cm.sup.2/Vsec.

Example 32

(186) Except for using a sintered oxide compact that includes Ge in the In.sub.2O.sub.3 at an atomic ratio of Ge/(In+Ge) of 0.05 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(187) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(188) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 210.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(189) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 710.sup.16 cm.sup.3, and the carrier mobility was 31 cm.sup.2/Vsec.

Example 33

(190) Except for using a sintered oxide compact that includes Sn in the In.sub.2O.sub.3 at an atomic ratio of Sn/(In+Sn) of 0.05 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(191) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(192) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 210.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(193) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 910.sup.16 cm.sup.3, and the carrier mobility was 35 cm.sup.2/Vsec.

Example 34

(194) Except for performing an annealing process in an air atmosphere for 30 minutes at 200 C., an oxynitride semiconductor thin film was obtained in the same was as in Example 1.

(195) The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 810.sup.20 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(196) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 910.sup.16 cm.sup.3, and the carrier mobility was 6 cm.sup.2/Vsec.

Example 35

(197) Except for performing an annealing process in an air atmosphere for 30 minutes at 200 C., an oxynitride semiconductor thin film was obtained in the same was as in Example 5.

(198) The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 110.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(199) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 110.sup.15 cm.sup.3, and the carrier mobility was 7 cm.sup.2/Vsec.

Comparative Example 1

(200) Except for employing a gas mixture of Ar and O.sub.2 as the sputtering gas so that the oxygen concentration became 1.5% by volume, an oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(201) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(202) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 1. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 210.sup.20 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this comparative example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(203) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 210.sup.19 cm.sup.3, and the carrier mobility was 22 cm.sup.2/Vsec.

Comparative Example 2

(204) Except for employing a gas mixture of Ar and O.sub.2 as the sputtering gas so that the oxygen concentration became 1.5% by volume, an oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(205) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(206) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 1. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 210.sup.20 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this comparative example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(207) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 310.sup.17 cm.sup.3, and the carrier mobility was 14 cm.sup.2/Vsec.

Comparative Example 3

(208) Except for performing an annealing process in an air atmosphere for 30 minutes at 180 C., an oxynitride semiconductor thin film was obtained in the same was as in Example 5.

(209) The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was amorphous. After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm.

(210) As described above, the oxynitride thin film of Comparative Example 3 was not crystallized, so secondary ion mass spectrometry and Hall effect measurement were not performed.

Comparative Example 4

(211) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga) of 0.25 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(212) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(213) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 110.sup.21 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(214) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 210.sup.14 cm.sup.3, and the carrier mobility was 4 cm.sup.2/Vsec.

Comparative Example 5

(215) Except for using a sintered oxide compact that includes Ga in the In.sub.2O.sub.3 at an atomic ratio of Ga/(In+Ga) of 0.10 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(216) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(217) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2 except that the heat treatment time was 0.5 minutes.

(218) The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was amorphous. After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm.

(219) As described above, the oxynitride thin film of Comparative Example 5 was not crystallized, so secondary ion mass spectrometry and Hall effect measurement were not performed.

Comparative Example 6

(220) Except for the O.sub.2 concentration in the sputtering gas being 1.5% by volume and the N.sub.2 concentration being 0.3% by volume, the oxynitride semiconductor thin film was obtained in the same was as in Example 5.

(221) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(222) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised only the In.sub.2O.sub.3 phase of Bixbyite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 310.sup.20 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this comparative example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(223) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 110.sup.19 cm.sup.3, and the carrier mobility was 24 cm.sup.2/Vsec.

Comparative Example 7

(224) Except for using a sintered oxide compact that includes Zn in the In.sub.2O.sub.3 at an atomic ratio of Zn/(In+Zn) of 0.65 as the sputtering target, the oxynitride semiconductor thin film was obtained in the same way as in Example 1.

(225) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(226) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 1. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was crystallized, and comprised the ZnO phase of Wurtzite structure. Then secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 810.sup.20 atoms/cm.sup.3. From these results, it was understood that in the oxynitride semiconductor thin film of this comparative example, N was solid-soluted in the In.sub.2O.sub.3 phase.

(227) After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, the Hall effect of the obtained oxynitride semiconductor thin film was measured using a Hall effect measurement device, and as a result, it was confirmed that the carrier density was 610.sup.19 cm.sup.3, and the carrier mobility was 26 cm.sup.2/Vsec.

Comparative Example 8

(228) Except for the O.sub.2 concentration in the sputtering gas being 1.5% by volume and the N.sub.2 concentration being 6.0% by volume, the oxynitride semiconductor thin film was obtained in the same was as in Example 5.

(229) The composition of the metal component included in the obtained oxynitride semiconductor thin film was measured by ICP atomic emission spectrometry, and as a result, it was confirmed that the composition was nearly the same as that of the sintered oxide compact. Moreover, the crystal structure of the oxynitride semiconductor thin film was measured by x-ray diffraction, and as a result, it was confirmed that this oxynitride semiconductor thin film was amorphous.

(230) Next, an annealing process was performed on this oxynitride semiconductor thin film under the same conditions as in Example 2. The oxynitride semiconductor thin film after annealing was then similarly measured using x-ray diffraction, and as a result, it was confirmed that the oxynitride semiconductor thin film was amorphous. After that, the thickness of the obtained oxynitride thin film was measured using a profilometer, and as a result, the thickness was confirmed to be 50 nm. Moreover, secondary ion mass spectrometry was performed, and as a result, it was confirmed that this oxynitride semiconductor thin film included N at about 210.sup.22 atoms/cm.sup.3.

(231) As described above, the oxynitride semiconductor thin film of Comparative Example 8 was not crystallized, so Hall effect measurement was not performed.

(232) TABLE-US-00002 TABLE 1 Film Formation Annealing Film Amount of N Carrier Carrier N.sub.2 conc. Temp. Time Thickness Crystal Added Element included Density Mobility (%) ( C.) (min) (nm) Structure (atomic ratio) (atom/cm.sup.3) (cm.sup.3) (cm.sup.2/V .Math. s) Ex. 1 1.5 300 30 50 b 8 10.sup.20 5 10.sup.16 29 Ex. 2 1.5 400 30 50 b 8 10.sup.20 2 10.sup.16 30 Ex. 3 5.7 300 30 50 b 5 10.sup.21 8 10.sup.15 27 Ex. 4 5.7 400 30 50 b Ga(0.10) 5 10.sup.21 4 10.sup.15 30 Ex. 5 1.5 300 30 50 b Ga(0.10) 1 10.sup.21 7 10.sup.14 28 Ex. 6 1.5 400 30 50 b Ga(0.10) 1 10.sup.21 4 10.sup.14 30 Ex. 7 0.5 400 30 50 b Ga(0.10) 4 10.sup.20 1 10.sup.15 28 Ex. 8 1.5 400 120 50 b Ga(0.10) 1 10.sup.21 2 10.sup.14 20 Ex. 9 1.5 400 60 50 b Ga(0.10) 1 10.sup.21 3 10.sup.14 27 Ex. 10 1.5 400 5 50 b Ga(0.10) 1 10.sup.21 6 10.sup.14 30 Ex. 11 1.5 400 1 50 b Ga(0.10) 1 10.sup.21 1 10.sup.15 30 Ex. 12 5.7 300 30 50 b Ga(0.10) 8 10.sup.21 6 10.sup.14 26 Ex. 13 5.7 400 30 50 b Ga(0.10) 8 10.sup.21 3 10.sup.14 28 Ex. 14 1.5 400 30 15 b Ga(0.10) 3 10.sup.21 6 10.sup.14 26 Ex. 15 1.5 400 30 200 b Ga(0.10) 8 10.sup.20 3 10.sup.14 29 Ex. 16 1.5 400 30 50 b Ga(0.10) Y(0.05) 4 10.sup.21 3 10.sup.14 27 Ex. 17 1.5 400 30 50 b Ga(0.10) La(0.05) 2 10.sup.21 2 10.sup.14 26 Ex. 18 1.5 400 30 50 b Ga(0.05) 8 10.sup.20 7 10.sup.14 29 Ex. 19 1.5 400 30 50 b Ga(0.08) 9 10.sup.20 5 10.sup.14 29 Ex. 20 1.5 400 30 50 b Ga(0.12) 2 10.sup.21 3 10.sup.14 27 Ex. 21 1.5 400 30 50 b Ga(0.15) 3 10.sup.21 2 10.sup.14 26 Ex. 22 1.5 400 30 50 b Ga(0.20) 4 10.sup.21 1 10.sup.14 25 Ex. 23 1.5 400 30 50 b Zn(0.10) 9 10.sup.20 2 10.sup.15 12 Ex. 24 1.5 400 30 50 b Ti(0.10) 2 10.sup.21 6 10.sup.14 8 Ex. 25 1.5 400 30 50 b W(0.10) 9 10.sup.20 7 10.sup.14 10 Ex. 26 1.5 400 30 50 b Mg(0.10) 9 10.sup.20 1 10.sup.15 8 Ex. 27 1.5 400 30 50 b Al(0.10) 3 10.sup.21 8 10.sup.14 22 Ex. 28 1.5 400 30 50 b Y(0.10) 3 10.sup.21 3 10.sup.15 20 Ex. 29 1.5 400 30 50 b La(0.10) 2 10.sup.21 1 10.sup.15 18 Ex. 30 1.5 400 30 50 b Sc(0.10) 2 10.sup.21 6 10.sup.15 17 Ex. 31 1.5 400 30 50 b Si(0.05) 4 10.sup.21 8 10.sup.16 29 Ex. 32 1.5 400 30 50 b Ge(0.05) 2 10.sup.21 7 10.sup.16 31 Ex. 33 1.5 400 30 50 b Sn(0.05) 2 10.sup.21 9 10.sup.16 35 Ex. 34 1.5 200 30 50 b Ga(0.10) 8 10.sup.20 9 10.sup.16 6 Ex. 35 1.5 200 30 50 b Ga(0.10) 1 10.sup.21 1 10.sup.15 7 CE1 0 300 30 50 b 2 10.sup.20 2 10.sup.19 22 CE2 0 300 30 50 b Ga(0.10) 2 10.sup.20 3 10.sup.17 14 CE3 1.5 180 30 50 a Ga(0.10) CE4 1.5 400 30 50 b Ga(0.25) 1 10.sup.21 2 10.sup.14 4 CE5 1.5 400 0.5 50 a Ga(0.10) CE6 0.3 400 30 50 b Ga(0.10) 3 10.sup.20 1 10.sup.19 24 CE7 1.5 300 30 50 w Zn(0.65) 8 10.sup.20 6 10.sup.19 26 CE8 6.0 400 30 50 a Ga(0.10) 2 10.sup.22 CE) Comparative Example *Cristal Structure - b: Bixbyite structure, w: Wurtzite structure, a; amorphous

TFT Element Characteristic Evaluation

Example 36

(233) A 50 nm thick amorphous oxynitride semiconductor thin film was formed on a SiO.sub.2 film of a 300 nm thick Si wafer substrate on which SiO.sub.2 film was formed by thermal oxidation using a sintered oxide compact that included Ga in In.sub.2O.sub.3 at an atomic ratio Ga/(In+Ga) of 0.10 as the sputtering target.

(234) The obtained amorphous oxynitride semiconductor thin film was crystallized by performing an annealing process in an air atmosphere for 30 minutes at 300 C., and as a result, the Si substrate, SiO.sub.2 film and crystalline oxynitride semiconductor thin film were taken to be a gate electrode, gate insulation layer and channel layer, respectively.

(235) After that, a source electrode and a drain electrode comprising an Au/Ti layered film were formed by sequentially forming a 5 nm thick Ti film and a 100 nm thick Au film on the surface of the channel layer by a direct-current magnetron sputtering method, to obtain a thin-film transistor (TFT element) having the construction illustrated in FIG. 1. The film formation conditions for the source electrode and the drain electrode were the same as the film formation conditions for the oxynitride semiconductor thin film except that the sputtering gas was only Ar, and the direct-current electric power was changed to 50 W.

(236) Furthermore, patterning using a metal mask was performed on the source electrode and drain electrode to obtain a TFT element having a channel length of 100 m and channel width of 450 m.

(237) The operating characteristics of this TFT element were investigated using a semiconductor parameter analyzer (4200SCS, manufactured by TFF Corporation Keithley Instruments), and as a result, the operating characteristics as a TFT element could be confirmed.

EXPLANATION OF REFERENCE NUMBERS

(238) 1 Gate electrode 2 Gate insulation layer 3 Channel layer 4 Source electrode 5 Drain electrode