Compositions and methods for making silicon containing films

Abstract

Described herein are low temperature processed high quality silicon containing films. Also disclosed are methods of forming silicon containing films at low temperatures. In one aspect, there are provided silicon-containing film having a thickness of about 2 nm to about 200 nm and a density of about 2.2 g/cm.sup.3 or greater wherein the silicon-containing thin film is deposited by a deposition process selected from a group consisting of chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), cyclic chemical vapor deposition (CCVD), plasma enhanced cyclic chemical vapor deposition (PECCVD, atomic layer deposition (ALD), and plasma enhanced atomic layer deposition (PEALD), and the vapor deposition is conducted at one or more temperatures ranging from about 25° C. to about 400° C. using an alkylsilane precursor selected from the group consisting of diethylsilane, triethylsilane, and combinations thereof.

Claims

1. A method for depositing a silicon-containing film on at least one surface of a device comprising a metal oxide, the method comprising: providing the at least one surface of the device in a reaction chamber; introducing an alkylsilane precursor selected from the group consisting of diethylsilane and triethylsilane into the reaction chamber; introducing into the reaction chamber an oxygen source; and depositing by a PECVD deposition process the silicon containing film on the at least one surface of the device at one or more reaction temperatures ranging from 25° C. to 150° C. wherein the silicon containing film comprises a thickness ranging from about 2 nanometers to about 200 nanometers and a density of about 2.25 g/cm.sup.3 or greater, wherein the metal oxide comprises at least one member selected from the group consisting of indium gallium zinc oxide, indium tin oxide, aluminum indium oxide, zinc tin oxide, zinc oxynitride, magnesium zinc oxide, zinc oxide, lnGaZnON, ZnON, ZnSnO, CdSnO, GaSnO, TiSnO, CuAlO, SrCuO, and LaCuOS, wherein the silicon-containing film has a hydrogen content of about 5 atomic % or less, and wherein the silicon-containing film has a O/Si ratio that ranges from about 1.9 to about 2.1.

2. The method of claim 1 wherein the device further comprises a gate electrode.

3. The method of claim 1 wherein the alkylsilane precursor comprises diethylsilane.

4. The method of claim 1 wherein the oxygen source is selected from the group consisting of water (H.sub.2O), oxygen (O.sub.2), oxygen plasma, ozone (O.sub.3), NO, N.sub.2O, carbon monoxide (CO), carbon dioxide (CO.sub.2) and combinations thereof.

5. The method of claim 1, wherein the deposition process is plasma enhanced chemical vapor deposition (PECVD) with dual RF frequency sources.

6. The method of claim 1, wherein the alkylsilane precursor comprises triethylsilane.

7. The method of claim 1 wherein the silicon-containing film having a leakage current less than 10.sup.−7 A/cm.sup.2 below electric field 6 MV/cm and the breakdown voltage is higher than 7 MV/cm.

8. A method for depositing a silicon containing film on at least one surface in a thin film transistor device, comprising: providing the at least one surface of the thin film transistor in a reaction chamber; introducing an alkylsilane precursor selected from the group consisting of diethylsilane and triethylsilane into the reaction chamber; introducing into the reaction chamber an oxygen source; and depositing via a PECVD deposition process the silicon containing film on the at least one surface of the thin film transistor device at one or more reaction temperatures ranging from 25° C. to 150° C. wherein the silicon containing film comprises a thickness ranging from about 2 nanometers to about 200 nanometers and a density of about 2.2 g/cm.sup.3 or greater, and wherein the silicon-containing film having a leakage current less than 10.sup.−7 A/cm.sup.2 below electric field 6 MV/cm and the breakdown voltage is higher than 7 MV/cm.

9. The method of claim 8, wherein the alkylsilane precursor comprises diethylsilane.

10. The method of claim 8, wherein the oxygen source is selected from the group consisting of water (H.sub.2O), oxygen (O.sub.2), oxygen plasma, ozone (O.sub.3), NO, N.sub.2O, carbon monoxide (CO), carbon dioxide (CO.sub.2) and combinations thereof.

11. The method of claim 8, wherein the deposition process comprises plasma enhanced chemical vapor deposition (PECVD) with dual RF frequency sources.

12. The method of claim 8, wherein the silicon containing layer is a gate insulation layer in a thin film transistor device.

13. The method of claim 8 wherein the silicon-containing film has a O/Si ratio which ranges from about 1.9 to about 2.1.

Description

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

(1) FIG. 1A shows the effect of film thickness on measured density for diethylsilane (2ES) films deposited using the BL-2 process conditions described in Table 1 of the Examples at 3 different temperatures: 400° C., 300° C., and 200° C.

(2) FIG. 1B shows the effect of film thickness on measured density for diethylsilane (2ES) films deposited using the BL-3 process conditions described in the Table 1 of the Examples at 3 different temperatures: 400° C., 300° C., and 200° C.

(3) FIG. 1C shows the effect of film thickness on measured density for tetraethoxysilane (TEOS) films deposited using the BL-2 process conditions described in the Table 1 of the Examples at 3 different temperatures: 400° C., 300° C., and 200° C.

(4) FIG. 1D shows the effect of film thickness on measured density for TEOS films deposited using the BL-3 process conditions described in the Table 1 of the Examples at 3 different temperatures: 400° C., 300° C., and 200° C.

(5) FIG. 2A shows the effect of film thickness on measured density for triethylsilane (3ES) films deposited using the BL-2 process conditions described in Table 1 of the Examples at 3 different temperatures: 400° C., 300° C., and 200° C.

(6) FIG. 2B shows the effect of film thickness on measured density for triethylsilane (3ES) films deposited using the BL-3 process conditions described in Table 1 of the Examples at 3 different temperatures: 400° C., 300° C., and 200° C.

(7) FIG. 3 shows FTIR spectra of thin (e.g., 76 nanometers (nm)) and thick films (e.g., 678 nm) of a diethylsilane (2ES) film deposited using the BL-2 process conditions described in Table 1 of the Examples at 400° C.

(8) FIG. 4A shows a comparison of dielectric constant (“K”) values of TEO-deposited films and 2ES-deposited films deposited using the BL-1 process conditions described in Table 1 at 3 different temperatures: 400° C., 300° C., and 200° C.

(9) FIG. 4B shows a comparison of wet etch rate (WER) of TEO-deposited films and 2ES-deposited films deposited using the BL-1 process conditions described in Table 1 at 3 different temperatures: 400° C., 300° C., and 200° C.

(10) FIG. 5 shows a comparison of the leakage current vs. electric field deposited TEOS films and the 2ES-deposited films deposited using the BL-3 process conditions described in Table 1 at 300° C.

(11) FIG. 6 shows a comparison of the flatband voltage (Vfb) vs. thickness measured in Angstroms (Å) for 2ES and TEOS SiO.sub.2 deposited films using conditions in Table 1.

(12) FIGS. 7a, 7b, 7c, and 7d provide examples of various embodiments of the apparatus described herein.

(13) FIG. 8 provides the relationship between leakage current measured in amperes versus electric field measured in (MV/cm) for 3ES films that were deposited at the following temperatures: 100° C., 125° C., and 150° C. using the process conditions in Table 2.

(14) FIG. 9 provides the wet etch rate of for 3ES films that were deposited at the following temperatures: 100° C., 125° C., and 150° C. using the process conditions in Table 2.

(15) FIG. 10 provides the relationship between leakage current measured in amperes versus electric field measured in (MV/cm) for 2ES films that were deposited at 100° C. using the process conditions in Table 3.

(16) FIG. 11 provides the relationship between the percentage change ii dielectric constant (K) and density for the low temperature oxide film described in Example 6.

DETAILED DESCRIPTION OF THE INVENTION

(17) Apparatuses comprising metal oxides or transparent metal oxides such as, for example, IGZO-based TFTs, are being implemented for display devices such as without limitation mobile displays. In one particular embodiment wherein the composition of the transparent metal oxide comprises IGZO, the thermal budget, which relates to the upper limit of the processing temperature that the apparatus can be subjected to, requires one or more gate insulation films be deposited at a temperature of 300° C. or less. In this or other embodiments, the one or more gate insulation layers comprises a stoichiometric or non-stoichiometric silicon oxide or silicon dioxide film having a density of about 2.2 g/cm.sup.3 or greater and a thickness that ranges from about 2 nanometers to about 200 nms. In this regard, the desired properties for a silicon containing film that can be used as one or more gate insulation layers for a metal oxide layer in a display device comprise one or more of the following: a deposition temperature of about 400° C. or less; a density of about 2.2 g/cm.sup.3 or 2.2 g/cc or greater; a conformality of about 50% or greater; a O/Si ratio that ranges from about 1.9 to about 2.1 (as measured by X-ray photospectrometry XPS); a leakage current density of about 1×10.sup.7 A/cm.sup.2 or less up to 7 MV/cm; and combinations thereof. In addition to the foregoing, in certain embodiments, the silicon containing film or layer has a hydrogen content of about 5 atomic percent (%) or less when measured using an analytical technique such as Rutherford backscattering, hydrogen forward scattering (HFS) or other methods. Also disclosed herein are methods for forming these silicon containing films at temperatures of about 400° C. or less for use as gate insulation layers. This invention will enable end users to obtain higher quality devices; e.g. faster IGZO-based TFTs and/or cheaper production by lowering processing temperature and enabling alternative substrates among other options.

(18) Described herein is a method to deposit a silicon containing film that can be employed as one or more gate insulation layers for a display device which comprises at least one silicon-containing layer and at least one transparent metal oxide layer. The term gate insulation layer could mean, without limitation, a passivation layer, a gate dielectric layer, an etch stop layer, or other suitable layer in a display device such as a TFT device, a OLED device, a LED device or other display devices. The term silicon-containing films as used herein can mean a silicon, amorphous silicon, crystalline silicon, microcrystalline silicon, polycrystalline silicon, stoichiometric or non-stoichiometric silicon oxide, stoichiometric or non-stoichiometric silicon dioxide, carbon doped silicon oxide, silicon carbo-nitride, and silicon oxynitride films. Of the foregoing, the one or more silicon-containing films are comprised of silicon oxide or silicon dioxide. The term “metal oxide” or “transparent metal oxide” means one or more layers within the device that is suitable for use in a display device. In this regard, the metal oxide layer exhibits one or more the following properties: has requisite transparency for use in a display device, exhibits high electron mobility, and can be manufactured at low processing temperatures (e.g., 300° C. or below). Examples of metal oxides include but are not limited to, Indium Gallium Zinc Oxide (IGZO), a-IGZO (amorphous indium gallium zinc oxide), Indium Tin Zinc Oxide (ITZO), Aluminum Indium Oxide (AlInOx), Zinc Tin Oxide (ZTO), Zinc Oxynitride (ZnON), Magnesium Zinc Oxide, zinc oxide (ZnO), InGaZnON, ZnON, ZnSnO, CdSnO, GaSnO, TiSnO, CuAlO, SrCuO, LaCuOS, GaN, InGaN, AlGaN or InGaAlN and combinations thereof. In addition to the one or more gate insulation layers and metal oxide layer, the display device may further include, without limitation, gate electrode layer(s), source drain layer(s), and other layers. The apparatus and method described herein may be used to deposit the at least one silicon-containing and metal oxide layer onto at least a portion of a substrate. Examples of suitable substrates include but are not limited to, glass, plastics, stainless steel, organic or polymer films, silicon, SiO.sub.2, Si.sub.3N.sub.4, OSG, FSG, silicon carbide, hydrogenated silicon carbide, silicon nitride, hydrogenated silicon nitride, silicon carbonitride, hydrogenated silicon carbonitride, boronitride, antireflective coatings, photoresists, organic polymers, porous organic and inorganic materials, metals such as copper, aluminum, chromium, molybdenum and gate electrodes such as but not limited to TiN, Ti(C)N, TaN, Ta(C)N, Ta, W, WN, silicon, ITO or other gate electrodes. The silicon-containing films are compatible with a variety of subsequent processing steps such as, for example, chemical mechanical planarization (CMP) and anisotropic etching processes. In one particular embodiment, the silicon-containing layer described herein has a dielectric constant that ranges from about 4.0 to about 5.5 or from about 4.0 to 4.5.

(19) FIGS. 7a through 7d provide various examples of embodiments of the apparatus described herein. In one embodiment 10 of the apparatus described herein and shown in FIG. 7a, the silicon-containing film is deposited as a single gate insulation layer 30 onto at least a portion of a gate electrode and a transparent metal oxide 20 is deposited on the gate insulation layer 30 that can be use, for example, in a display device. In an alternative embodiment 100 of the apparatus described herein and shown in FIG. 7b, the silicon-containing film is deposited onto one or more silicon-containing films below the metal oxide layer 120 which is shown as gate insulation layer 2, or 140 on FIG. 7b, and gate insulation layer 1, or 130 on FIG. 7b, to provide a double gate insulation layer structure or multi-layered gate insulation layer structure. In one embodiment, the silicon-containing films in the double gate insulation or multi-layered are different types of silicon-containing films. Alternatively, the silicon-containing films in the double or multi-layered structures can be the same types of silicon-containing films but alternated in a variety of ways, such as without limitation, SixOy, SiwNz, SixOy, and SiwNz; SixOy, SixOy, and SiwNz; SixOy, SiwNz, and SiwNz; and various combinations thereof. While the exemplary structures shown in FIGS. 7a through 7d show the one or more gate insulation layers deposited onto at least a portion of a gate electrode and then a transparent metal oxide film is deposited on the gate insulation layer(s), it is understood that the one or more layers are not limited to arrangement of layers depicted in FIGS. 7a through 7d and may be above or below metal oxide layer and one or more gate insulation layer(s), sandwiched, imbedded, surrounded, have intervening layers which are not silicon-containing, or any other spatial relationships with respect to each other and are subsequently not limited thereto.

(20) In one particular embodiment, the display device comprises one gate insulation layer deposited onto the gate electrode and then metal oxide layer is deposited on the gate insulation layer such as that shown in FIG. 7a wherein the gate insulation layer 1 comprises silicon oxide, silicon carboxide, preferably with a density about 2.2 g/cm.sup.3 or greater and a thickness ranging from about 2 nm to about 200 nm. In another particular embodiment, the display device comprises at least two gate insulation layers deposited onto the gate electrode and then metal oxide layer is deposited on the gate insulation layers such as that shown in FIG. 7b wherein the gate insulation layers comprise: a silicon-containing layer selected from the group consisting of silicon nitride and silicon carbonitride as gate insulation layer 1 or 130 and a silicon-containing layer selected from the group consisting of silicon carbide, silicon oxide, silicon carboxide, and silicon carboxynitride as gate insulation layer 2 or 140, preferably a silicon oxide with density about 2.2 g/cm.sup.3 or greater and a thickness which ranges from about 2 nm to about 200 nm. In one particular embodiment of the apparatus 100 shown in 7b, the transparent metal oxide layer 120 comprises IGZO and the at least two gate insulation layers act as a bi-layer gate dielectric. In yet another particular embodiment, the display device comprises at least one gate insulation layers deposited onto the metal oxide layer such as that shown in FIGS. 7c and 7d or apparatus 200 and 300 respectively. In one particular embodiment of FIG. 7c, apparatus 200 comprises a transparent metal oxide 220 and a gate insulation layer deposited thereupon wherein the gate insulation layer 1 or 230 comprises silicon oxide, silicon carboxide, preferably with a density about 2.2 g/cm.sup.3 or greater and a thickness ranging from about 2 nm to about 200 nm. In one particular embodiment of the apparatus 300 shown in 7d, the metal oxide layer 320 comprises IGZO and the at least two gate insulation layers can also act as a barrier to protect the IGZO film from diffusion of atmospheric impurities (e.g., be hermetic) while not impacting to any great significance the resistivity of the IGZO film post treatment. In this particular embodiment, the apparatus comprises a high density silicon nitride film (e.g., having a density of 2.4 g/cm.sup.3 or greater) as gate insulation layer 1 or 330 and is deposited by the prescursor trisilylamine (TSA) and ammonia (NH.sub.3) at one or more temperatures that range from 80 to 400° C. The device further comprises a silicon oxide film as gate insulation layer 2 or 340 to prevent the diffusion of active hydrogen contained in the silicon nitride to the IGZO located beneath the oxide. The silicon oxide film can be deposited at one or more temperatures ranging from 80° C. to 400° C. It is desirable that the precursor selected and the deposition process conditions impart a minimum of hydrogen, hydroxyl groups, or other moieties such as carbon, hydrocarbons or other functional groups which can react with the metal oxide such as IGZO and lower. It is desirable that the precursor selected and the deposition process conditions impart a minimum of hydrogen, hydroxyl groups, or other moieties such as carbon, hydrocarbons or other functional groups which may react with the transparent metal oxide such as IGZO and lower. In this regard, the gate insulation layer 2 is deposited from a silicon-containing precursor for example diethylsilane(2ES) or triethylsilane(3ES) which has less Si—H groups than silane because it is known that Si—H may react with the transparent metal oxide, thus damaging the electric property of the transparent metal oxide layer. While not being bound to theory, for an apparatus having at least two gate insulation layers comprising a silicon oxide layer and a silicon nitride layer, the Applicants believe that the selection of the silicon oxide precursor and its deposition parameters and the silicon nitride and its deposition parameters are important to ensure that the attributes of one or more gate insulation layers do not adversely impact the resistivity of the transparent metal oxide layer.

(21) The method used to form the one or more silicon-containing film(s) or layer(s) and the metal oxide layer(s) are referred to herein as deposition processes. Examples of suitable deposition processes for the method disclosed herein include, but are not limited to, chemical vapor depositions (CVD), cyclic CVD (CCVD), MOCVD (Metal Organic CVD), thermal chemical vapor deposition, plasma enhanced chemical vapor deposition (“PECVD”), high density PECVD, photon assisted CVD, plasma-photon assisted (“PPECVD”), cryogenic chemical vapor deposition, chemical assisted vapor deposition, hot-filament chemical vapor deposition, CVD of a liquid polymer precursor, deposition from supercritical fluids, and low energy CVD (LECVD). In certain embodiments, the films are deposited via atomic layer deposition (ALD), plasma enhanced ALD (PEALD) or plasma enhanced cyclic CVD (PECCVD) process. As used herein, the term “chemical vapor deposition processes” refers to any process wherein a substrate is exposed to one or more volatile precursors, which react and/or decompose on the substrate surface to produce the desired deposition. As used herein, the term “atomic layer deposition process” refers to a self-limiting (e.g., the amount of film material deposited in each reaction cycle is constant), sequential surface chemistry that deposits films of materials onto substrates of varying compositions. Although the precursors, reagents and sources used herein may be sometimes described as “gaseous”, it is understood that the precursors can also be liquid or solid which are transported with or without an inert gas into the reactor via direct vaporization, bubbling or sublimation. In some case, the vaporized precursors can pass through a plasma generator. In one embodiment, the one or more films is deposited using an ALD process. In another embodiment, the one or more films is deposited using a CCVD process. In a further embodiment, the one or more films is deposited using a thermal CVD process. The term “reactor” as used herein, includes without limitation, reaction chamber or deposition chamber.

(22) In certain embodiments, the method disclosed herein avoids pre-reaction of the precursors by using ALD or CCVD methods that separate the precursors prior to and/or during the introduction to the reactor. In this connection, deposition techniques such as ALD or CCVD processes are used to deposit the film. In one embodiment, the film is deposited via an ALD process by exposing the substrate surface alternatively to the one or more the silicon-containing precursor, oxygen source, nitrogen-containing source, or other precursor or reagent. Film growth proceeds by self-limiting control of surface reaction, the pulse length of each precursor or reagent, and the deposition temperature. However, once the surface of the substrate is saturated, the film growth ceases.

(23) The selection of precursor materials for deposition depends upon the desired resultant dielectric material or film. For example, a precursor material may be chosen for its content of chemical elements, its stoichiometric ratios of the chemical elements, its deposition rate control, and/or the resultant dielectric film or coating that are formed under CVD. The precursor material may also be chosen for various other characteristics such as cost, non-toxicity, handling characteristics, ability to maintain liquid phase at room temperature, volatility, molecular weight, etc. The thin (e.g., about 2 nm to about 200 nm) silicon-containing films disclosed herein are deposited using a silicon-containing precursor, such as but not limited to alkylsilanes having the following formula: R.sup.1R.sup.2R.sup.3SiH wherein R.sup.1 is chosen from the group consisting of a C.sub.1-10 linear or branched alkyl group; a C.sub.4 to C.sub.10 cyclic alkyl group; a C.sub.3 to C.sub.12 alkenyl group; a C.sub.3 to C.sub.12 alkynyl group; and a C.sub.6 to C.sub.10 aryl group; R.sup.2 and R.sup.3 are independently selected from hydrogen; a C.sub.1-10 linear or branched alkyl group; a C.sub.4 to C.sub.10 cyclic alkyl group; a C.sub.3 to C.sub.12 alkenyl group; a C.sub.3 to C.sub.12 alkynyl group; and a C.sub.6 to C.sub.10 aryl group and wherein R.sup.1 and any one of R.sup.2 and R.sup.3 can be linked to form a ring when R.sup.2 and R.sup.3 are not hydrogen.

(24) Examples of alkylsilanes, that can be used in the method described herein or to deposit on or more silicon-containing layers in the apparatus described herein, include but are not limited to, diethylsilane (2ES), di(tert-butyl)silane, di(iso-propyl)silane, di(sec-butyl)silane, di(iso-butyl)silane, di(tert-amyl)silane, triethylsilane (3ES), tri(tert-butyl)silane, tri(iso-propyl)silane, tri(sec-butyl)silane, tri(iso-butyl)silane, tri(tert-amyl)silane, tert-butyldiethylsilane, tert-butyldipropylsilane, diethylisopropylsilane, cyclopentylsilane, and phenylsilane.

(25) In the formulas above and throughout the description, the term “alkyl” denotes a linear, or branched functional group having from 1 to 10 or 1 to 4 carbon atoms. Exemplary alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, iso-pentyl, tert-pentyl, hexyl, isohexyl, and neohexyl. In certain embodiments, the alkyl group may have one or more functional groups such as, but not limited to, an alkoxy group, a dialkylamino group or combinations thereof, attached thereto. In other embodiments, the alkyl group does not have one or more functional groups attached thereto.

(26) In the formulas above and throughout the description, the term “cyclic alkyl” denotes a cyclic functional group having from 3 to 12 or from 4 to 10 carbon atoms. Exemplary cyclic alkyl groups include, but are not limited to, cyclobutyl, cyclopentyl, cyclohexyl, and cyclooctyl groups.

(27) In the formulas above and throughout the description, the term “aryl” denotes an aromatic cyclic functional group having from 6 to 12 carbon atoms. Exemplary aryl groups include, but are not limited to, phenyl, benzyl, chlorobenzyl, tolyl, and o-xylyl.

(28) In the formulas above and throughout the description, the term “alkenyl group” denotes a group which has one or more carbon-carbon double bonds and has from 2 to 12 or from 2 to 6 carbon atoms. Exemplary alkenyl groups include, but are not limited to, vinyl or allyl groups

(29) In the formulas above and throughout the description, the term “alkynyl group” denotes a group which has one or more carbon-carbon triple bonds and has from 2 to 12 or from 2 to 6 carbon atoms.

(30) In the formulas above and throughout the description, the term “alkoxy” denotes an alkyl group which has is linked to an oxygen atom (e.g., R—O) and may have from 1 to 12, or from 1 to 6 carbon atoms. Exemplary alkoxy groups include, but are not limited to, methoxy (—OCH.sub.3), ethoxy (—OCH.sub.2CH.sub.3), n-propoxy (—OCH.sub.2CH.sub.2CH.sub.3), and iso-propoxy (—OCHMe.sub.2).

(31) In certain embodiments, one or more of the alkyl group, alkenyl group, alkynyl group, alkoxy group, and/or aryl group in the formulas above may be substituted or have one or more atoms or group of atoms substituted in place of, for example, a hydrogen atom. Exemplary substituents include, but are not limited to, oxygen, sulfur, halogen atoms (e.g., F, Cl, I, or Br), nitrogen, and phosphorous. In other embodiments, one or more of the alkyl group, alkenyl group, alkynyl group, alkoxy group, and/or aryl in the formula may be unsubstituted.

(32) In certain embodiments, substituents R.sup.1 and R.sup.2 or substitutents R.sup.1 and R.sup.3 are linked in the above formula are linked to form a ring structure when R.sup.2 and R.sup.3 are not hydrogen. As the skilled person will understand, where R.sup.1 and R.sup.2 or R.sup.1 and R.sup.3 are linked together to form a ring, R.sup.1 will include a bond (instead of a hydrogen substituent) for linking to R.sup.2 or R.sup.3 and vice versa. Thus, in the example above R.sup.1 may be selected from a linear or branched C.sub.1 to C.sub.10 alkylene moiety; a C.sub.2 to C.sub.12 alkenylene moiety; a C.sub.2 to C.sub.12 alkynylene moiety; a C.sub.4 to C.sub.10 cyclic alkyl moiety; and a C.sub.6 to C.sub.10 arylene moiety. In these embodiments, the ring structure can be unsaturated such as, for example, a cyclic alkyl ring, or saturated, for example, an aryl ring. Further, in these embodiments, the ring structure can also be substituted or substituted. In other embodiments, substituent R.sup.1 and R.sup.2 or substituent R.sup.1 and R.sup.3 are not linked.

(33) In certain embodiments, the thin silicon oxide containing films used as gate insulation layers are deposited using the methods described above are formed in the presence of oxygen using an oxygen source, reagent or precursor comprising oxygen. Suitable oxygen source gases include but not limited to, for example, water (H.sub.2O) (e.g., deionized water, purifier water, and/or distilled water), oxygen (O.sub.2), oxygen plasma, ozone (O.sub.3), NO, N.sub.2O, carbon monoxide (CO), carbon dioxide (CO.sub.2) and combinations thereof. The deposition methods disclosed herein may involve one or more inert gases for purging, controlling the plasma or as carrier gases. In certain embodiments, the silicon-containing precursor may have one or more substituents comprising oxygen atoms. In these embodiments, the need for an oxygen source during the deposition process may be minimized. In other embodiments, the silicon-containing precursor has one of more substituents comprising oxygen atoms and also uses an oxygen source.

(34) In certain embodiments, the oxygen source comprises an oxygen source gas that is introduced into the reactor at a flow rate ranging from about 1 to about 2000 square cubic centimeters (sccm) or from about 1 to about 1000 sccm. The oxygen source can be introduced for a time that ranges from about 0.1 to about 100 seconds. In one particular embodiment, the oxygen source comprises water having a temperature of 10° C. or greater. In embodiments wherein the film is deposited by an ALD or a cyclic CVD process, the precursor pulse can have a pulse duration that is greater than 0.01 seconds, and the oxygen source can have a pulse duration that is less than 0.01 seconds, while the water pulse duration can have a pulse duration that is less than 0.01 seconds. In yet another embodiment, the purge duration between the pulses that can be as low as 0 seconds or is continuously pulsed without a purge in-between. The oxygen source or reagent is provided in a molecular amount less than a 1:1 ratio to the silicon precursor, so that at least some carbon is retained in the as deposited dielectric film.

(35) In certain embodiments, the silicon-containing layer further comprises nitrogen. In these embodiments, the silicon-containing layer deposited using the methods described herein are formed in the presence of nitrogen-containing source. In one particular embodiment such as that depicted in FIG. 7b, the silicon-containing film 140 or gate insulation layer 1 comprises silicon nitride and is deposited using the methods described above are formed in the presence of nitrogen using a nitrogen, reagent or precursor comprising nitrogen. A nitrogen-containing source may be introduced into the reactor in the form of at least one nitrogen source and/or may be present incidentally in the other precursors used in the deposition process. Suitable nitrogen-containing source gases may include, for example, ammonia, hydrazine, monoalkylhydrazine, dialkylhydrazine, nitrogen, nitrogen/hydrogen, ammonia plasma, nitrogen plasma, nitrogen/hydrogen plasma, NF.sub.3 and mixture thereof. In one particular embodiment, NF.sub.3 is used to reduce the hydrogen content in the resulting films because hydrogen can react with the metal oxide thereby adversely effecting the performance of the display devices. In certain embodiments, the nitrogen-containing source comprises an ammonia plasma or hydrogen/nitrogen plasma source gas that is introduced into the reactor at a flow rate ranging from about 1 to about 2000 square cubic centimeters (sccm) or from about 1 to about 1000 sccm. The nitrogen-containing source can be introduced for a time that ranges from about 0.1 to about 100 seconds.

(36) The deposition methods disclosed herein may involve one or more purge gases. The purge gas, which is used to purge away unconsumed reactants and/or reaction byproducts, is an inert gas that does not react with the precursors. Exemplary purge gases include, but are not limited to, argon (Ar), nitrogen (N.sub.2), helium (He), xenon (Xe), neon, hydrogen (H.sub.2), and mixtures thereof. In certain embodiments, a purge gas such as Ar is supplied into the reactor at a flow rate ranging from about 10 to about 2000 sccm for about 0.1 to 1000 seconds, thereby purging the unreacted material and any byproduct that may remain in the reactor.

(37) The respective step of supplying the precursors, oxygen source, the nitrogen-containing source, and/or other precursors, source gases, and/or reagents may be performed by changing the time for supplying them to change the stoichiometric composition of the resulting dielectric film.

(38) Energy is applied to the at least one of the silicon-containing precursor, oxygen-containing source, nitrogen-containing source, reducing agent, other precursors and/or combination thereof to induce reaction and to form the silicon-containing film or coating on the substrate. Such energy can be provided by, but not limited to, thermal, plasma, pulsed plasma, helicon plasma, high density plasma, inductively coupled plasma, X-ray, e-beam, photon, remote plasma methods, and combinations thereof. In certain embodiments, a secondary RF frequency source can be used to modify the plasma characteristics at the substrate surface. In embodiments wherein the deposition involves plasma, the plasma-generated process may comprise a direct plasma-generated process in which plasma is directly generated in the reactor, or alternatively a remote plasma-generated process in which plasma is generated outside of the reactor and supplied into the reactor.

(39) The silicon-containing precursors may be delivered to the reaction chamber such as a CVD or ALD reactor in a variety of ways. In one embodiment, a liquid delivery system may be utilized. In an alternative embodiment, a combined liquid delivery and flash vaporization process unit may be employed, such as, for example, the turbo vaporizer manufactured by MSP Corporation of Shoreview, Minn., to enable low volatility materials to be volumetrically delivered, which leads to reproducible transport and deposition without thermal decomposition of the precursor. In liquid delivery formulations, the precursors described herein may be delivered in neat liquid form, or alternatively, may be employed in solvent formulations or compositions comprising same. Thus, in certain embodiments, the precursor formulations may include solvent component(s) of suitable character as may be desirable and advantageous in a given end use application to form a film on a substrate.

(40) In certain embodiments, the gas lines connecting from the precursor canisters to the reaction chamber are heated to one or more temperatures depending upon the process requirements and the container of the at least one silicon-containing precursor is kept at one or more temperatures for bubbling. In other embodiments, a solution comprising the at least one silicon-containing precursor is injected into a vaporizer kept at one or more temperatures for direct liquid injection.

(41) The rate of the deposition of the silicon-containing films or silicon oxide films described herein can be in the range of 0.1 nm to 5000 nm per minute. The rate can be controlled by varying any one or more of the following non-limiting parameters: deposition temperature, the vaporizer temperature, the flow of the line flow controller (LFC), the flow rate of the reactive of O.sub.2 gas and/or the pressure at the CVD reactor. Choice of precursor can also determine the deposition rate.

(42) The temperature of the reactor or deposition chamber for the deposition may range from one of the following endpoints: ambient temperature 25° C.; 50° C.; 75° C.; 100° C.; 125° C.; 150° C.; 175° C.; 200° C.; 225° C.; 250° C.; 300° C.; 325° C.; and any combinations thereof. In this regard, the deposition temperature may range from about 25° C. to about 325° C., 25 to about 300° C., 100° C. to 250° C., 150° C. to 325° C., or 100° C. to 300° C., or any combinations of the temperature end-points described herein.

(43) The pressure of the reactor or deposition chamber may range from about 0.1 Torr to about 1000 Torr. The respective step of supplying the precursors, the oxygen source, and/or other precursors, source gases, and/or reagents may be performed by changing the time for supplying them to change the stoichiometric composition of the resulting dielectric film.

(44) The substrate may be exposed to a pre-deposition treatment such as, but not limited to, a plasma treatment, chemical treatment, ultraviolet light exposure, electron beam exposure, and/or other treatments to affect one or more properties of the film. For example, it may be advantageous to subject the IGZO film to a N.sub.2O or O.sub.2 or O.sub.3 plasma treatment or an O.sub.3 chemical treatment to ensure complete oxidation of the IGZO. This allows for the semiconducting properties to be preserved or enhanced prior to film deposition.

(45) The resultant films or coatings may be exposed to a post-deposition treatment such as, but not limited to, a plasma treatment, chemical treatment, ultraviolet light exposure, electron bean exposure, and/or other treatments to affect one or more properties of the film.

(46) In the method described herein, it is understood that the steps of the methods described herein may be performed in a variety of orders, may be performed sequentially or concurrently (e.g., during at least a portion of another step), and any combination thereof. The respective step of supplying the precursors and the nitrogen-containing source gases may be performed by varying the duration of the time for supplying them to change the stoichiometric composition of the resulting dielectric film.

(47) The resultant dielectric films or coatings may be exposed to a post-deposition treatment such as, but not limited to, a plasma treatment, chemical treatment, ultraviolet light exposure, electron beam exposure, and/or other treatments to affect one or more properties of the film.

(48) In certain embodiments, it may be advantageous to deposit a layer which has a composition gradient from top to bottom. e.g., a film comprising SiCO or SiO2 as one layer and comprising SiNC or Si.sub.3N.sub.4 as the other layer. In these embodiments, the film is deposited from a first reagent mixture comprising a silicon containing precursor and a oxygen containing precursor, eg 2ES and O.sub.2, ozone, or N.sub.2O, and then replacing the flow of the oxygen containing gas with an nitrogen containing gas, e.g., N.sub.2, ammonia, or hydrazine. If the silicon containing precursor already contains nitrogen ten the second step may be performed using just an inert gas or hydrogen. The changing of the oxygen to nitrogen containing or inert gases can be gradual or abrupt resulting in either a gradiated layer or a bilayer structure. Such a bilayer or gradiated layer is advantageous for some applications such as, without limitation, different application needs for metal oxide and IGZO interfaces to the silicon containing film.

(49) In addition to the foregoing, the thin silicon-containing films have applications which include, but are not limited to, computer chips, optical devices, magnetic information storages, coatings on a supporting material or substrate, microelectromechanical systems (MEMS), nanoelectromechanical systems, thin film transistor (TFT), and liquid crystal displays (LCD).

(50) The following examples illustrate the method for preparing the silicon containing film described herein and are not intended to limit it in any way.

EXAMPLES

General Deposition Conditions

(51) In the following examples, unless stated otherwise, properties were obtained from sample films that were deposited onto medium resistivity (8-12 Ωcm) single crystal silicon wafer substrates. All depositions were performed on an Applied Materials Precision 5000 system in a 200 mm DXZ chamber fitted with an Advanced Energy 2000 RF generator, using a TEOS process kit. The PECVD chamber is equipped with direct liquid injection delivery capability. All precursors were liquids with delivery temperatures dependent on the precursor's boiling point. Unless otherwise stated, typical precursor flow rates were 25-150 sccm, plasma power density was 0.5-3 W/cm.sup.2, and pressure was 0.75-12 torr. Thickness and refractive index (RI) at 648 nm) were measured by a reflectometer. A mercury probe was utilized for all film measurements where dielectric constant, electrical breakdown field and leakage are presented. X-ray Photoelectron Spectroscopy (XPS) and Rutherford Backscattering Spectrometry (RBS)/Hydrogen Forward Scattering (HFS) were performed to determine the film composition. Hydrogen Forward Scattering (HFS) was used to quantify the hydrogen content in the films.

(52) The etch test is carried out in 6:1 BOE solution. Exemplary dielectric films are placed in HF solution for 30 seconds, followed by rinsing in deionized (DI) water and drying before being measured again for the loss of the material during the etch. The process is repeated till the films are completely etched. The etch rate is then calculated from the slope of the etch time vs thickness etched.

(53) FTIR data was collected on the wafers using a Thermo Nicolet 750 system in a nitrogen purged cell. Background spectra were collected on similar medium resistivity wafers to eliminate CO.sub.2 and water from the spectra. Data was obtained in the range of from 4000 to 400 cm.sup.−1 by collecting 32 scans with a resolution of 4 cm.sup.−1. The OMNIC software package was used to process the data.

(54) Dielectric constants, k, are calculated from a C—V curve measured with a MDC Mercury Probe. The dielectric constant is then calculated from formula k=the capacitance x the contact area/the thickness of the film.

(55) Density was measured by X-Ray Reflectivity (XRR). All samples with nominal thicknesses<200 nm were scanned using low-resolution optics (error bar+/−0.01 g/cm.sup.3). All samples with nominal thicknesses>200 nm were scanned using high-resolution optics (error bar+/−0.005 g/cm.sup.3). Samples were scanned over the range 0.2≤2≤1 using a step size of 0.001 and a count time of 1 s/step. Data were analyzed using a two-layer model with the substrate defined as Si and film as SiO.sub.2.

(56) Table 1 provides a summary of the three different process conditions that were used for compare the deposition performance of the precursors studied. These are labeled herein as BL-1, BL-2 and BL-3.

(57) TABLE-US-00001 TABLE 1 Summary of process conditions used for comparing precursors Process Condition BL-1 BL-2 BL-3 Precursor Flow 107 45 27 (sccm) He (carrier, sccm) 1000 1000 1000 O.sub.2 (oxygen source) 1100 1100 700 Pressure (torr) 8.2 8.2 3.5 Spacing (mils) 500 500 800 Power Density 2.27 2.27 0.87 (W/cm.sup.2)

Example 1

Deposition of Diethylsilane (2ES) and Triethylsilane (3ES) at Deposition Temperatures of 200° C., 250° C., 300° C., 350° C., and 400° C.

(58) Silicon oxide films were deposited from the silicon precursors 2ES and 3ES SiO.sub.2 films were deposited at different temperature and process conditions using the general deposition conditions described above. BL-1 and BL-2 conditions are identical except for precursor flow. While BL-1 process has the highest deposition rate due to higher precursor flow, it is not the most important criterion for gate insulation layers. BL-3 is a lower pressure condition and generally gives poorer films. A comparison of same amount of Si-feed between precursors was used to understand whether a truly better quality film can be produced. As seen in FIGS. 1A and 2A, generally higher densities are obtained for films>200 nm with BL-2 process (>2.2 g/cc) and FIG. 1B, 2B; slightly lower densities were obtained with BL-3 process (˜2.2 g/cc). The BL-1 process conditions were not explored in further detail as the densities were expected to be in between those of the BL-2 and BL-3 process conditions.

(59) FIG. 1A shows the effect of film thickness on measured density for 2ES films deposited by BL-2 process condition at 3 temperatures: 400° C., 300° C., and 200° C. Referring to FIG. 1A, the density of the films surprisingly increased as the thickness decreased, particularly at a deposition condition of 300° C. FIG. 1B shows the effect of film thickness on measured density for 2ES films deposited by BL-3 process condition at 3 temperatures: 400° C., 300° C., and 200° C. Referring to FIG. 1B, the density of the films surprisingly increased as the thickness decreased, this is particularly apparent at a deposition condition of 300° C.

(60) FIG. 2A shows the effect of film thickness on measured density for 3ES films deposited by BL-2 process conditions at 3 temperatures: 400° C., 300° C., and 200° C. Surprisingly, the density of the films increased as the thickness decreased, especially at 200° C.

(61) FIG. 2B shows the effect of film thickness on measured density for 3ES films deposited by BL-3 process conditions at 3 temperatures: 400° C., 300° C., and 200° C. Surprisingly, like in FIG. 2A, the density of the films increased as the thickness decreased, especially at 200° C.

(62) FIG. 3 provides a comparison of FTIR spectra of thin (76 nanometer (nm)) and thick films (678 nm) of 2ES oxide deposited by the BL2 condition at 400° C. The spectra indicate that both films are SiO.sub.2 only. The absence of Si—H or C—H peaks in the FTIR spectra for the 2ES-deposited films indicates good decomposition of the precursor molecule during the deposition process even at low temperatures. Referring again to FIG. 3, the difference between the shoulder to peak ratio of the ˜1050 cm.sup.−1 peak as thickness increases has been explained by different mechanisms such as strain relaxation, geometric effects, in-situ annealing effects and oxygen deficiency. This effect is observed in high quality thermally grown SiO.sub.2 films.

(63) The H-content in atomic % and measured by RBS for the DES deposited films which were deposited at a BL-1 process condition at deposition temperature of 350° C. and 250° C. were 2.0% (density of 2.25 g/cm.sup.3) and 2.8% (density of 2.26 g/cm.sup.3), respectively. This shows that both DES deposited films had very low total hydrogen content (<5%) as measured by RBS/HFS. This is also confirmed by a FTIR analysis of these films which showed no detectable Si—H and very minimal Si—OH bonding.

Example 2

Comparison of Silicon Oxide Films Deposited Using BL2 Process Condition and Tetraethoxysilane (TEOS) vs. Diethysilane (2ES)

(64) SiO.sub.2 films were deposited using the process conditions described above in the general deposition conditions and in Table 1. In FIGS. 1C and 1D, TEOS deposited silicon oxide films having different thicknesses were deposited at the same BL-2 and BL-3 process conditions described above in Table 1. Referring to FIG. 1C, compared to the 2ES and 3ES films deposited using BL-2 at identical deposition temperatures (see FIG. 1A and FIG. 2A), at lower deposition temperatures such as 200° C., the TEOS-deposited films generally had lower density than the 2ES or 3ES films. A similar effect was observed when comparing the data in FIG. 1D with the data for the 2ES films and 3ES films in FIGS. 1B and 2B) for the same deposition temperatures. The 2ES and 3ES films generally exhibited equal or higher density for the thinner films. In general, the density of TEOS film drops to <2.2 g/cc for <200 nm films for both process conditions.

(65) FIG. 4A shows a comparison of dielectric constant (“K”) values of TEOS-deposited films and 2ES-deposited films which were deposited using the BL-1 condition described above at 3 different temperatures: 400° C., 300° C., and 200° C. The dielectric constant of a good quality thermally grown or convention chemical vapor deposited SiO.sub.2 is 4.0. For PECVD oxides deposited at 400° C., the K value varies as a function of process conditions. It is possible to optimize the process to get K values of 4.1 to 4.3 for a good quality 400° C. PECVD SiO.sub.2 films. However, at increasingly lower deposition temperatures, the film quality typically degrades as evidenced by poorer film density and the increasing ability of the film to absorb moisture, which thereby increases the K value. FIG. 4A shows that the 2ES-deposited films have better K values than the TEOS-deposited films at deposition temperatures of 200° C. and 300° C. This indicates that these films are denser and of better quality than the TEOS films deposited at the same process condition. Similar behavior was also seen for the BL-2 and BL-3 process conditions.

(66) FIG. 4B shows a comparison of wet etch rate (WER) of TEOS-deposited films and 2ES-deposited films which were deposited using the BL-1 condition described above at 3 different temperatures: 400° C., 300° C., and 200° C. FIG. 4B shows that the 2ES deposited films had lower WER than the TEOS deposited films at all temperatures. This confirms the superior quality of the 2ES films for certain applications. Similar behavior was also seen for the BL-2 and BL-3 process conditions.

(67) FIG. 5 shows the leakage current versus electric field for the 300° C. deposited TEOS films vs. the DES-deposited films at the BL3 processing condition. The leakage current for the DES-deposited films remained low whereas the TEOS-deposited films exhibited poor leakage. Thoughout all the other deposition temperatures and process conditions, DES was clearly better than TEOS.

(68) The interface and bulk charges in 2ES and TEOS SiO.sub.2 films are compared in FIG. 6 by tracking the flatband voltage (Vfb). For TEOS films, the flatband voltage becomes more negative as the film becomes thicker, indicating more bulk charges (e.g., defective bonds) in the film. In contrast, 2ES films showed the ability to keep Vfb close to 0 V, minimizing both interface and bulk charges. In this plot, the precursors are not compared at the same process condition as their film thicknesses were different; and that affects the Vfb value.

(69) The stoichiometry of the SiO.sub.2 was measured by XPS and the O/Si ratio was found to be 2.17 for TEOS oxide and 2.1 for 2ES oxide at 200° C. and BL-1 condition. Without being bound by theory, it is proposed that an O/Si ratio>2.0 is possibly due to Si—OH groups in the film. It is seen that 2ES has less deviation from stoichiometry and appears to be consistent with the dielectric constant and WER data.

(70) Without being bound by theory, the precursors described herein have the capability to deposit thinner films (e.g., 2 nm to 200 nm) of higher quality due to such surface mobility and chemical reactivity improvements. This is surprising because the thinner DES or 3ES films had better density.

Example 3

Deposition of Thin SiO.SUB.2 .Films Using 3ES with High Density and Electric Properties

(71) Process conditions for the 3ES silicon oxide films were screened using a design of experiment (DOE) methodology summarized below: precursor flow from 10 to 200 sccm; O.sub.2/He flow from 100 to 1000 sccm, pressure from 0.75 to 10 torr; Low-frequency (LF) power 0 to 100 W; and deposition temperature ranged from 25 to 350° C. The DOE experiments were used to determine what process parameters produced the optimal film for use as a gate insulating layer in a display device.

(72) SiO.sub.2 films were deposited using the precursor 3ES at even lower deposition temperatures, such as 100° C., 125° C. and 150° C. then described above in the previous examples. By optimizing the process parameters, such as precursor flow, chamber pressure and power density, high density and thin SiO.sub.2 films are obtained. Table 2 shows a summary of the three process conditions used for 3ES film deposited at different temperatures 100° C., 125° C. and 150° C., as well as certain film properties, such as thickness, k value and density which were measured using the methods described herein in the general deposition conditions. In general, the films deposited using 3ES had a thickness less than 200 nm, a k value between 4 to 5, and a density higher than 2.2 g/cm.sup.3.

(73) FIG. 8 shows the leakage current vs electric field for the 3ES deposited films at the three different deposition temperatures. The leakage current for the 3ES-deposited films is comparable to thermal oxide leakage current. The break down voltage is comparable or even better then thermal oxide. Breakdown voltage refers to the voltage at which the electric current begins to flow when a formed film is placed between the electrodes and voltage is applied. Since thin films such as silicon oxide films play the role of blocking the flow of charges in a semiconductor device, breakdown voltage is a very important indicator as an electrical property of a thin film. In order for a film, such as a silicon oxide film, to be used as an insulation material in a semiconductor device, the material should have a breakdown voltage of about 8˜12 MV/cm in general (so-called intrinsic breakdown region, exhibited by a thermally oxidized silicon oxide film). If there are any weak spots or defects in the films, the breakdown voltage is reduced. FIG. 8 shows that the breakdown voltage of the 3ES-deposited silicon oxide is comparable to or even better then the thermal oxide.

(74) The wet etch rate was also obtained for these films using also studied with 0.5% HF and the method described above in the general deposition conditions. FIG. 9 provides the WER of the 3ES-deposited SiO.sub.2 films at 100° C., 125° C. and 150° C. using the process conditions shown in Table 2. The WER of the film does not appear to have a significant big change when the film is deposited at lower deposition temperatures. This confirms the superior quality of the 3ES films at low temperatures.

(75) TABLE-US-00002 TABLE 2 Summary of process conditions used for 3ES film deposited at different temperatures 100° C., 125° C. and 150° C. and the films properties. Process conditions 3ES 100° C. 3ES 125° C. 3ES 150° C. Precursor flow 27 48 27 (sccm) He (carrier, sccm) 1000 1000 1000 O.sub.2 (sccm) 1000 1000 1000 Pressure (torr) 9.2 9.2 9.2 Spacing (mils) 500 500 500 Power density 1.75 2.5 2.5 (W/cm.sup.2) Film thickness (nm) 165 113 173 Film Density (g/cm.sup.3) 2.26 2.29 2.28 K value 4.67 4.62 4.42

Example 4

Deposition of Thin SiO.SUB.2 .Films Using 2ES with High Density and Electric Properties

(76) Process conditions for the 2ES silicon oxide films were screened at T<200 C. using a design of experiment (DOE) methodology summarized below: typical precursor flow rates were 25-150 sccms, plasma power density was 0.5-3 W/cm.sup.2, and pressure was 0.75-12 torr.

(77) The SiO.sub.2 films are also deposited at a deposition temperature of 100° C. using 2ES. By optimizing the process parameters, such as precursor flow, chamber pressure and power density, and other process conditions, high density and thin SiO.sub.2 films are obtained. Table 3 shows a summary of the process conditions used for 2ES film deposited at 100° C. as well as the certain film properties, such as thickness, k value and density which were obtained using the methods described herein. The film had a thickness less than 200 nm and density higher than 2.2 g/cc.

(78) FIG. 10 shows the leakage current vs. electric field for the 2ES film deposited at 100° C. with process conditions in Table 3. The leakage current for the 2ES-deposited films is comparable to thermal oxide leakage current. FIG. 10 shows that the break down voltage for the 100° C. deposited 2ES film is comparable or even better then thermal oxide.

(79) TABLE-US-00003 TABLE 3 Summary of process conditions used for 2ES-deposited SiO.sub.2 film at 100° C. and film properties. Process conditions 2ES 100° C. Precursor flow (sccm) 38 He (carrier, sccm) 1000 O.sub.2 (sccm) 1000 Pressure (Torr) 10 Spacing (mils) 500 Power density (W/cm.sup.2) 1.5 Film thickness (nm) 195 Density (g/cm.sup.3) 2.21 K value 5.05

Example 5

Deposition of Thin SiO.SUB.2 .Films Using 3ES at 100° C. With High Density

(80) The present example is used to show the deposition of thin and high density SiO.sub.2 film using 3ES provides a wide process window. Table 4 provides the process conditions for two 3ES deposited, SiO.sub.2 films and film properties at different precursor flows, 29 sccm and 68 sccm. Although the table shows a wide range of deposition rates, high density films were obtained.

(81) TABLE-US-00004 TABLE 4 Summary of Process Conditions for 100° C. 3ES Depositions Process conditions 100° C. 100° C. Precursor flow (sccm) 29 68 He (carrier, sccm) 1000 1000 O.sub.2 (sccm) 1000 1000 Pressure (Torr) 9.2 9.2 Spacing (mils) 500 500 Power density (W/cm.sup.2) 2.5 2.5 Deposition rate (nm/min) 27 89 Film thickness (nm) 160 222 K value 4.77 5.07 Density (g/cm.sup.3) 2.26 2.23

Example 6

Compositional Data of Thin SiO.SUB.2 .Films Deposited Using 3ES at 100° C. and 150° C.

(82) XPS is used to exam the carbon concentration in the film. The relative atomic percentage is measured at the surface and after 50 nm sputtering. Table 5 shows the process conditions and film properties of two 3ES films deposited at 100° C. and 150° C. Table 6 provides the XPS data of the films. No carbon was detected in the bulk film and the O/Si ratio of the film was very close to 2.0 or stoichiometric.

(83) TABLE-US-00005 TABLE 5 Summary of process conditions and film properties of 3ES films. Process conditions 3ES 150° C. 3ES 100° C. Precursor flow (sccm) 68 50 He (carrier, sccm) 1000 1000 O.sub.2 (sccm) 1000 1000 Pressure (Torr) 9.2 9 Spacing (mils) 500 700 Power density (W/cm.sup.2) 2.5 2.0 Film thickness (nm) 210 206 K value 4.69 4.84 Density (g/cm.sup.3) 2.25 2.27

(84) TABLE-US-00006 TABLE 6 XPS data of 3ES films deposited Using Table 5 Process Conditions. Relative Atomic Percent Sample ID Location Condition O N C Si O/Si 3ES A As Received 62.0 ND 8.5 29.5 2.10 150° C. After 500 Å 66.8 ND ND 33.2 2.01 Sputter B As Received 63.0 ND 9.4 27.7 2.28 After 500 Å 67.3 ND ND 32.7 2.06 Sputter 3ES A As Received 57.5 ND 15.7  26.9 2.1 100° C. After 500 Å 66.7 ND 33.3 2.0 Sputter B As Received 61.4 ND 9.4 29.3 2.1 After 500 Å 66.5 ND 33.5 2.0 Sputter

Example 6

Stability Analysis of Thin SiO.SUB.2 .Films Deposited Using 3ES Stability

(85) The optimized low temperature oxide has good stability as shown herein in Tables 7a and 7b and FIG. 11. Tables 7a and 7b shows the k value change of several SiO.sub.2 films deposited by 3ES after 3 weeks in air. It can be seen that the film in table 7a are very stable after 3 weeks (less than 2.5% change in k value) while those in table 7b are not so stable (3-20% change in k value). The average density of the films in table 7a is higher than in table 7b, which is consistent with stability. So the optimized film has good stability despite being very thin. In general, a trend is seen between density and k stability, with the highest density (2.28 g/cc) film showing 0% change in k value and the films with <2.23 g/cm.sup.3 showing significant change in k value (>3%).

(86) The electric breakdown field and leakage current are also measured for the 3ES SiO.sub.2 films after 3 months The leakage current and break down electric field for the 3ES-deposited films is comparable to thermal oxide, showing a leakage current less than 10.sup.−7 A/cm.sup.2 below electric field 6 MV/cm and the breakdown voltage higher than 7 MV/cm.

(87) Table 7a shows the stability of K value of the low temperature oxide.

(88) TABLE-US-00007 Temperature (° C.) 100 100 125 125 125 150 150 150 Thickness (nm) 160 263 225 113 166 174 210 173 Density (g/cm.sup.3) 2.26 2.26 2.26 2.29 2.26 2.26 2.25 2.28 K 4.77 4.98 4.80 4.61 4.62 4.40 4.69 4.42 K (3 weeks later) 4.87 4.97 4.91 4.62 4.72 4.36 4.73 4.42

(89) Table 7b shows the stability of K value of the low temperature oxide.

(90) TABLE-US-00008 Temperature (° C.) 100 100 125 150 150 150 Thickness 223 260 443 232 224 263 Density 2.23 2.21 2.23 2.25 2.26 2.22 K 5.07 5.43 5.07 4.74 4.47 4.77 K (3 weeks 5.24 6.05 6.00 4.96 4.74 5.48 later)

(91) The working example and embodiments of this invention listed above, are exemplary of numerous embodiments that may be made of this invention. It is contemplated that numerous materials other than those specifically disclosed may be made. Numerous other configurations of the process may also be used, and the materials used in the process may be elected from numerous materials other than those specifically disclosed.