SEMICONDUCTOR CONTAINING AMORPHOUS TELLURIUM OXIDE, THIN FILM TRANSISTOR INCLUDING SAME, AND FABRICATION METHOD THEREFOR
20260040600 ยท 2026-02-05
Inventors
Cpc classification
H10D30/0316
ELECTRICITY
C23C14/542
CHEMISTRY; METALLURGY
H10D30/675
ELECTRICITY
H10P14/22
ELECTRICITY
C01P2002/72
CHEMISTRY; METALLURGY
International classification
H10D30/01
ELECTRICITY
C23C14/54
CHEMISTRY; METALLURGY
Abstract
Disclosed are a semiconductor comprising amorphous tellurium oxide, thin film transistor and method of fabricating same. In detail, a semiconductor comprising a chalcogen atom comprising at least one selected from the group consisting of a sulfur atom (S) and a selenium atom (Se); and tellurium composite comprising a tellurium (Te) atom and tellurium oxide. A thin film transistor (TFT) fabricated based on the TeO.sub.x channel layer according to the present disclosure exhibits excellent output/transfer characteristics and superior electrical performance with high hole field-effect mobility and a high on/off current ratio of 10.sup.7.
Claims
1. A semiconductor comprising: a chalcogen atom comprising at least one selected from the group consisting of a sulfur (S) atom and a selenium (Se) atom; and a tellurium composite comprising a tellurium (Te) atom and a tellurium oxide.
2. The semiconductor of claim 1, wherein the chalcogen atom is doped in the tellurium composite.
3. The semiconductor of claim 1, wherein the tellurium composite is represented by chemical formula 1 below, ##STR00005## in the chemical formula 1, x is 0.8x1.7.
4. The semiconductor of claim 3, wherein the tellurium oxide comprises a tellurium monoxide (TeO) and a tellurium dioxide (TeO.sub.2).
5. The semiconductor of claim 1, the semiconductor is represented by chemical formula 2 below, ##STR00006## in the chemical formula 2, M is sulfur (S) atom or selenium (Se) atom, x is 0.8x1.7 and M is 0.5 to 5 atom % of the total number of Te atom, O atom and the M atom.
6. The semiconductor of claim 1, wherein the semiconductor is amorphous.
7. The semiconductor of claim 1, wherein a tellurium semiconductor is p-type.
8. The semiconductor of claim 1, wherein the semiconductor is in an oxygen-deficient state.
9. The semiconductor of claim 8, wherein the tellurium atom of the semiconductor comprises an ionization state of Te.sup.4+, an ionization state of Te.sup.2+ and a non-ionization state of Te.sup.0.
10. The semiconductor of claim 1, wherein selenium atom of the semiconductor comprises an ionization state of Se.sup.2.
11. The semiconductor of claim 1, wherein the semiconductor is used in a semiconductor layer of a thin film transistor.
12. The semiconductor of claim 11, wherein the thickness of the semiconductor layer is 2 to 10 nm.
13. A method of fabricating a semiconductor layer, the method comprising: (a) preparing a mixture by mixing a chalcogen comprising at least one selected from the group consisting of a sulfur (S) atom and a selenium (Se) atom and a tellurium dioxide (TeO.sub.2); and (b) depositing the mixture to form a semiconductor layer comprising a semiconductor, wherein the semiconductor comprises a chalcogen atom comprising at least one selected from the group consisting of a sulfur (S) atom and a selenium (Se) atom; and a tellurium composite comprising a tellurium (Te) atom and a tellurium oxide.
14. The method of claim 13, wherein the deposition of step (b) is carried out by thermal deposition, sputtering, vapor phase chemical vapor deposition (CVD) or solution coating.
15. The method of claim 14, wherein the deposition of step (b) is carried out by thermal deposition or sputtering.
16. The method of claim 15, wherein a thermal deposition rate of the semiconductor layer is 1 to 100 /s when performing the thermal deposition.
17. The method of claim 13, wherein the molar ratio of the chalcogen and the tellurium dioxide (TeO.sub.2) of step (a) is 0.01:99.99 to 50:50 (mol:mol).
18. The method of claim 14, wherein a molar ratio of the tellurium and the oxygen of the semiconductor layer is controlled by regulating a partial pressure of oxygen and argon plasma when performing the sputtering of step (b).
19. The method of claim 13, further comprising, after step (b), (c) annealing the semiconductor layer of step (b) at a temperature in a range of 100 to 300 C. in air or oxygen atmosphere.
20. A method of fabricating a thin film transistor, the method comprising: (1) preparing a gate electrode/insulating layer laminate comprising a gate electrode and an insulating layer positioned on the gate electrode; (2) forming a semiconductor layer comprising a semiconductor on the insulating layer; and (3) forming a source electrode and a drain electrode on the semiconductor layer, wherein the semiconductor comprises a chalcogen atom comprising at least one selected from the group consisting of a sulfur (S) atom and a selenium (Se) atom; and a tellurium composite comprising a tellurium (Te) atom and a tellurium oxide.
Description
DESCRIPTION OF DRAWINGS
[0043] Since the accompanying drawings are intended to illustrate exemplary embodiments of the present disclosure, the technical ideas of the present disclosure should not be construed to be limited by the accompanying drawings.
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BEST MODE
[0069] Herein after, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings in such a manner that the ordinarily skilled in the art can easily implement the embodiments of the present disclosure.
[0070] But the description given below is not intended to limit the present disclosure to specific embodiments. In relation to describing the present disclosure, when the detailed description of the relevant known technology is determined to unnecessarily obscure the gist of the present disclosure, the detailed description may be omitted.
[0071] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present disclosure. As used herein, the singular forms a, an and the are intended to comprise the plural forms as well unless the context clearly indicates otherwise. It will be further understood that the terms comprise or have when used in the present disclosure specify the presence of stated features, integers, steps, operations, elements and/or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements and/or combinations thereof.
[0072] Terms comprising ordinal numbers used in the specification, first, second, etc. can be used to discriminate one component from another component, but the order or priority of the components is not limited by the terms unless specifically stated. These terms are used only for the purpose of distinguishing a component from another component. For example, without departing from the scope of the present disclosure, a first component may be referred to as a second component and a second component may be also referred to as a first component.
[0073] In addition, when it is mentioned that a component is formed, stacked or laminated on another component, it should be understood such that one component may be directly attached to or directly stacked on the front surface or one surface of the other component or an additional component may be disposed between them.
[0074] A semiconductor layer comprising an amorphous tellurium oxide, a thin film transistor and method of fabricating same will be described in detail. However, those are described as examples and the present disclosure is not limited thereto and is only defined by the scope of the appended claims.
[0075] The present disclosure provides a semiconductor comprising: a chalcogen atom comprising at least one selected from the group consisting of a sulfur (S) atom and a selenium (Se) atom; and a tellurium composite comprising a tellurium (Te) atom and a tellurium oxide.
[0076] In addition, the chalcogen atom may be doped in the tellurium composite.
[0077] In addition, the tellurium composite may be represented by chemical formula 1 below.
##STR00003## [0078] in the chemical formula 1, [0079] x is 0.8x1.7, preferably 1.0x1.5, more preferably 1.1x1.4. Here, when x is less than 0.8, a large number of TeTe bonds are comprised, so that the charge amount increases, which is undesirable as a transistor semiconductor layer. When x is more than 1.7, the charge amount is too low, which is undesirable.
[0080] In addition, the tellurium oxide may comprise a tellurium monoxide (TeO) and a tellurium dioxide (TeO.sub.2).
[0081] In addition, the semiconductor may be represented by chemical formula 2 below.
##STR00004## [0082] in the chemical formula 2, [0083] M is a sulfur (S) atom or a selenium (Se) atom, and [0084] x is 0.8x1.7, preferably 1.0x1.5, more preferably 1.1x1.4. Here, when x is less than 0.8, a large number of TeTe bonds are comprised, so that the charge amount increases, which is undesirable as a transistor semiconductor layer. When it exceeds 1.7, the charge amount is too low, which is undesirable.
[0085] M is 0.5 to 5 atom %, preferably 1 to 4.5 atom %, more preferably 1.5 to 4 atom % of the total number of Te atom, O atom and the M atom. Here, when M is less than 0.5 atom %, the hole mobility is low due to too low a doping amount, which is not desirable. When it exceeds 5 atom %, the current value is low, which is not desirable.
[0086] In addition, the semiconductor may be amorphous.
[0087] In addition, the tellurium semiconductor may be p-type.
[0088] In addition, the semiconductor may be in an oxygen-deficient state and the oxygen-deficient state means a state in which the ratio of oxygen in the stoichiometry ratio of tellurium (Te):oxygen (O) is less than 1:2.
[0089] In addition, the tellurium atom of the semiconductor may comprise an ionization state of Te.sup.4+, an ionization state of Te.sup.2+ and a non-ionization state of Te.sup.0 and wherein, the semiconductor may use a shallow acceptor state formed by the 5p-orbitals of Te.sup.2+ and Te.sup.0 as a hole conduction channel.
[0090] In addition, the selenium atom of the semiconductor may comprise an ionization state of Se.sup.2. Here, the partially empty 4p state can be used as a hole conduction channel as the Se.sup.2 of the semiconductor passivates the oxygen vacancy.
[0091] In addition, the semiconductor may be used in a semiconductor layer of a thin film transistor.
[0092] In addition, the thickness of the semiconductor layer may be 2 nm or more, preferably 2 to 100 nm. Here, when the thickness of the semiconductor layer is less than 2 nm, the charge amount is small and it is difficult to obtain sufficient thin film coverage, which is undesirable. When the thickness of the thin film is too thick, the charge amount is too high, which is undesirable as a semiconductor layer of a transistor.
[0093] Another aspect of the present disclosure provides a thin film transistor comprising: a gate electrode; an insulating layer positioned on the gate electrode; a semiconductor layer positioned on the insulating layer and comprising a semiconductor according to the present disclosure; and a source electrode and a drain electrode positioned apart from each other on the semiconductor layer.
[0094] In addition, the gate electrode may comprise at least one selected from the group consisting of n-doped silicon (n-doped Si), p-doped silicon (p-doped Si), gold (Au), silver (Ag), platinum (Pt), titanium (Ti), aluminum (Al), tungsten (W), magnesium (Mg), calcium (Ca), ytterbium (Yb), chromium (Cr), nickel (Ni), molybdenum (Mo), gold oxide, platinum oxide, silver oxide, palladium oxide, iron oxide, graphene, carbon nanotube (CNT), silver nanowire (Ag nanowire, Ag NW), indium tin oxide and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS).
[0095] In addition, the source electrode and the drain electrode may each comprise at least one selected from the group consisting of gold (Au), silver (Ag), platinum (Pt), titanium (Ti), aluminum (Al), tungsten (W), magnesium (Mg), calcium (Ca), ytterbium (Yb), chromium (Cr), nickel (Ni), molybdenum (Mo), gold oxide, platinum oxide, silver oxide, palladium oxide, iron oxide, graphene, carbon nanotube (CNT), silver nanowires (Ag NW), indium tin oxide and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS).
[0096] In addition, the insulating layer may comprise at least one selected from the group consisting of silicon dioxide, glass, quartz, alumina, silicon carbide, magnesium oxide, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polystyrene (PS), polyimide (PI), polyvinyl chloride (PVC), polyvinyl pyrrolidone (PVP), polyethylene (PE), silicon oxide (SiO.sub.2), germanium, polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), zirconium oxide (ZrO.sub.2), aluminum oxide (AlO.sub.2) and hafnium oxide (HfO.sub.2).
[0097] Another aspect of the present disclosure provides a method of fabricating a semiconductor layer, the method comprising: (a) preparing a mixture by mixing a chalcogen comprising at least one selected from the group consisting of a sulfur (S) atom and a selenium (Se) atom and a tellurium dioxide (TeO.sub.2); and (b) depositing the mixture to form a semiconductor layer comprising a semiconductor, wherein the semiconductor comprises a chalcogen atom comprising at least one selected from the group consisting of a sulfur (S) atom and a selenium (Se) atom; and tellurium composite comprising a tellurium (Te) atom and a tellurium oxide.
[0098] In addition, the deposition of step (b) may be carried out by thermal deposition, sputtering, vapor phase chemical vapor deposition (CVD) or solution coating.
[0099] In addition, the deposition of step (b) may be carried out by thermal deposition or sputtering.
[0100] In addition, a temperature of the substrate deposited in the thermal deposition may be a range of 15 to 35 C., preferably a room temperature.
[0101] In addition, a temperature of the substrate deposited in the sputtering may be a range of 15 to 35 C., preferably a room temperature.
[0102] In addition, the thermal deposition or the sputtering may be carried out under a vacuum pressure of 10.sup.3 Torr or less. Here, when it is carried out under a vacuum pressure exceeding 10.sup.3 Torr, the thermal deposition or the sputtering is undesirable because it may contain impurities.
[0103] In addition, when performing the thermal deposition, the thermal deposition rate may be 1 to 100 /s based on the semiconductor layer. Here, when the thermal deposition rate is less than 1 /s, the process time for thin film deposition is too long, which is undesirable. When it exceeds 100 /s, the surface roughness of the thin film increases, which is undesirable.
[0104] In addition, a molar ratio of the chalcogen and the tellurium dioxide (TeO.sub.2) in step (a) may be 0.01:99.99 to 50:50 (mol:mol), preferably 0.1:99.9 to 30:70. That is, the doping concentration is 0.01 mol to 50 mol, preferably 0.1 mol to 30 mol. The doping concentration is the ratio of the mole number of chalcogen (C) to the total mole number of chalcogen (C) and tellurium dioxide (T), (C/(C+T)100, mol/mol %). Here, when the molar ratio is less than 0.01:99.99, the doping effect is not effective, which is undesirable. When it exceeds 50:50, phase separation may occur, which is undesirable.
[0105] In addition, the molar ratio of tellurium and oxygen in the semiconductor layer can be controlled by regulating the partial pressure of oxygen and argon plasma during the sputtering in step (b).
[0106] In addition, the method (c) may comprise, after step (b), (c) annealing the semiconductor layer of step (b) at a temperature in a range of 100 to 300 C. in an air or an oxygen atmosphere.
[0107] In addition, the method may comprise, after step (c), (d) annealing at a temperature in a range of room temperature to 300 C. in air.
[0108] Another aspect of the present disclosure provides a method of fabricating a thin film transistor, the method comprising: (1) preparing a gate electrode/insulating layer laminate comprising a gate electrode and an insulating layer positioned on the gate electrode; (2) forming a semiconductor layer comprising a semiconductor on the insulating layer; and (3) forming a source electrode and a drain electrode on the semiconductor layer, wherein the semiconductor comprises, a chalcogen atom comprising at least one selected from the group consisting of a sulfur atoms(S) and a selenium atoms (Se); and a tellurium composite comprising a tellurium (Te) atoms and a tellurium oxide.
Mode for Disclosure
EXAMPLES
[0109] Hereinafter, the examples of the present disclosure will be described. However, the examples are for illustrative purposes, and the scope of the present disclosure is not limited by the examples.
Example 1: Fabrication of Selenium Doped Amorphous p-Channel Thin Film Transistor
Example 1-1:2 Atom % Se-Doped Tellurium Oxide
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[0111] In order to deposit a tellurium oxide-based semiconductor film, commercially available TeO.sub.2 powder (purity 97% or higher) was used as an evaporation source. Meanwhile, a small amount of chalcogen powder (S or Se) was mixed with TeO.sub.2, and after deposition, the atomic ratio of tellurium oxide on the surface of the semiconductor layer was observed as Te:O:Se=38:60:2 by XPS. However, the X-ray absorption results showed that the ratio of Te:O was 1:1.2, indicating that the amount of oxygen on the surface was greater. The TeO.sub.x-based film was deposited using a general thermal evaporator. The substrate temperature was 25 C., and the vacuum pressure before evaporation was below 10.sup.3 Torr. The distance between the substrate and the boat loaded with TeO.sub.2 was 2 to 50 cm. The deposition rate was 1 /s. The thickness of the TeO.sub.x films (1 to 100 nm) was monitored during the deposition process. The deposited samples were first annealed at 200 C. for 30 min in a N.sub.2-filled glove box, and then further annealed at 225 C. for 30 min in air. After that, the source/drain electrodes were deposited using Ni, respectively, to fabricate thin-film transistors (TFTs).
Example 1-2:4 Atom % Se-Doped Tellurium Oxide
[0112] A thin film transistor (TFT) was fabricated in the same manner as Example 1-1, with the exception that 4 atom & Se-doped tellurium oxide was deposited instead of that 2 atom & Se-doped tellurium oxide was deposited.
Comparative Example 1: Se-Undoped Tellurium Oxide
Comparative Example 1-1: Pristine Tellurium Oxide
[0113] A thin film transistor (TFT) was fabricated in the same manner as Example 1-1, with the exception that Se-undoped tellurium oxide was deposited instead of that 2 atom % Se-doped tellurium oxide was deposited.
TEST EXAMPLE
Test Example 1: Amorphous and Crystalline Thin Film
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Test Example 2: XANES (X-Ray Absorption Near-Edge Structure)
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Test Example 3: XPS Depth Profile Element Distribution
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Test Example 4: High-Resolution TEM
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Test Example 5: XPS Spectrum
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[0119] Referring to
Test Example 6: Transfer Characteristics of TeO.SUB.x.:Se TFT
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[0121] Referring to
Test Example 7: Transfer Curve of TeO.SUB.x.:Se TFT
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[0123] Referring to
Test Example 8: XPS Se 3p Spectrum
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Test Example 9: TFT Using TeO.SUB.x.:Se Channel
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Test Example 10: Electrical Characteristics of Amorphous P-Channel TeO.SUB.x.:Se TFTs
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Test Example 11: TFT Field Effect Hole Mobility (h)
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Test Example 12: Integrated Circuit of TFT-Based Oxide
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[0129] The scope of the present disclosure is defined by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as falling into the scope of the present disclosure.