Oxide semiconductor film, transistor, and method for manufacturing oxide semiconductor film

Abstract

An oxide semiconductor film having a hollandite structure and having a {100} orientation with respect to a crystal plane of a lower surface.

Description

Technical Field

[0001] This invention relates to oxide semiconductor films, transistors, and methods for manufacturing oxide semiconductor films. Background Technology

[0002] In recent years, oxide semiconductor films have been used not only in display transistors but also in FETs for memory (DRAM, NAND, ReRAM, FeRAM), FETs for logic ICs (CPU, MPU, BEOL, 3D-LSI, CMOS), and FETs for sensors (CMOS image sensors) and transistors (MOSFETs, power transistors, MESFETs). Research on improving the performance of oxide semiconductor films is ongoing. For example, Patent Document 1 discloses a method for manufacturing transistors that improves long-term reliability by reducing oxygen vacancies in oxide semiconductors.

[0003] Patent document 2 discloses an oxide semiconductor thin film manufactured using a sputtering target comprising a sintered body, the sintered body comprising an oxide containing indium (In), zinc (Zn) and aluminum (Al) and being InAlO3 (ZnO). m The compounds with homologous structures (m = 0.1 to 10) and the ferromanganese-structured compounds of In₂O₃ are also mentioned. Patent Document 2 discloses that, in oxide semiconductor films used in transistors, etc., from the perspective of preventing leakage current, normal on, and reduction of the on / off ratio when constructing the device, it is preferable to reduce the carrier concentration. On the other hand, it is required to obtain high mobility when the carrier concentration in the film is increased. This is because, in field-effect transistors, whether high mobility can be exhibited when the carrier concentration increases due to the field effect can be used as an indicator. In addition, the carrier concentration and mobility in the film can usually be determined by measuring the Hall effect. In this invention, the carrier concentration and mobility determined by measuring the Hall effect are referred to as carrier concentration and Hall mobility, respectively.

[0004] Currently, sputtering is widely used as a method for forming oxide semiconductor films for display applications (e.g., Patent Document 3). On the other hand, memory applications are attracting much attention as the next application direction for oxide semiconductor films. In memory applications, it is necessary to form oxide semiconductor films for three-dimensional structures, therefore, atomic layer deposition (hereinafter sometimes referred to as ALD) is gaining attention as a replacement for sputtering (e.g., Patent Document 4).

[0005] Existing technical documents Patent documents [Patent Document 1] Japanese Patent Application Publication No. 2014-57054 [Patent Document 2] Japanese Patent Application Publication No. 2014-051714 [Patent Document 3] Japanese Patent Publication No. 2016-511936 [Patent Document 4] International Publication No. 2021 / 106652 Summary of the Invention For applications such as higher-performance displays, memory, and sensors, there is a demand for oxide semiconductor films with low carrier concentration and higher Hall mobility even when the carrier concentration is high due to field effects. However, the oxide semiconductor films formed by the above-mentioned ALD have lower performance in these aspects.

[0006] It is known that carbon in oxide semiconductor films affects their electrical properties. Specifically, it is known that if silicon or carbon, which is a Group 14 element, is included as an impurity in an oxide semiconductor film, silicon or carbon becomes a donor, causing the oxide semiconductor film to become n-type. Therefore, Patent Document 1, concerning film formation by sputtering, describes setting the concentration of silicon or carbon in the oxide semiconductor film to 3 × 10⁻⁶. 18 / cm 3 the following.

[0007] Furthermore, Patent Document 1 describes that if hydrogen or moisture is contained as an impurity in the oxide semiconductor film, hydrogen becomes a donor and causes the oxide semiconductor film to become n-type. Therefore, it is preferable to perform film formation in an atmosphere controlled to be almost free of hydrogen and moisture (inert atmosphere, reduced pressure atmosphere, dry air atmosphere, etc.).

[0008] In this way, when forming oxide semiconductor films using conventional sputtering methods such as Patent Document 1, oxide semiconductor films with excellent electrical properties have always been manufactured by controlling the film to be as free of carbon and hydrogen as possible.

[0009] However, in the case of oxide semiconductor films formed by ALD, carbon and hydrogen remain in the formed oxide semiconductor film due to its film formation principle, so it is desirable to suppress the reduction of the electrical properties of the resulting oxide semiconductor film.

[0010] The inventors conducted in-depth research and found that: when the oxide semiconductor film formed by ALD has a ferromanganese oxide structure and a {100} orientation relative to the crystal plane of the underlying surface, it becomes an oxide semiconductor film with low carrier concentration and high Hall mobility, thus completing the present invention.

[0011] The purpose of this invention is to provide an oxide semiconductor film with low carrier concentration and high Hall mobility.

[0012] According to the present invention, the following oxide semiconductor films, etc., are provided.

[0013] 1. An oxide semiconductor film having a manganese oxide structure and having a {100} orientation relative to the crystal plane of the underlying surface.

[0014] 2. The oxide semiconductor film according to item 1, in measurements performed according to secondary ion mass spectrometry (SIMS), has a carbon concentration of 1 × 10⁻⁶. 18 atoms / cm 3 Above and 5×10 19 atoms / cm 3 The following areas.

[0015] 3. The oxide semiconductor film according to item 1 or 2, wherein the film thickness is less than 20 nm.

[0016] 4. The oxide semiconductor film according to any one of items 1 to 3, wherein indium oxide is contained as the main component.

[0017] 5. The oxide semiconductor film according to item 4, wherein the atomic ratio of In in the oxide semiconductor film relative to all metal elements ([In] / ([In]+[all metal elements other than In])×100) is 62 at% or more.

[0018] 6. The oxide semiconductor film according to item 4 or 5, further comprising Ga.

[0019] 7. The oxide semiconductor film according to item 6, wherein the atomic ratio of Ga in the oxide semiconductor film relative to all metal elements ([Ga] / ([Ga]+[all metal elements other than Ga])×100) is 30 at% or less.

[0020] 8. The oxide semiconductor film according to any one of claims 4 to 7, further comprising one or more additive elements selected from B, Al, Si, Sc, Zn, Ce, Y, Zr, Sn, Sm, Hf, Ta and Yb.

[0021] 9. The oxide semiconductor film according to item 8, wherein the total amount of the added elements contained in the oxide semiconductor film is less than or equal to the atomic ratio of all metal elements ([total amount of added elements] / ([total amount of added elements]+[all metal elements other than added elements])×100).

[0022] 10. The oxide semiconductor film according to any one of items 4 to 9, wherein at least one of the X-ray diffraction pattern in X-ray diffraction and the electron beam diffraction spot in electron beam diffraction shows a ferromanganese structure.

[0023] 11. The oxide semiconductor film according to any one of items 1 to 10, wherein the carrier concentration at room temperature is 1 × 10⁻⁶. 19 cm -3 the following.

[0024] 12. The oxide semiconductor film according to any one of items 1 to 11, having a Hall mobility of 30 cm⁻¹. 2 / Vs and above.

[0025] 13. The oxide semiconductor film according to any one of items 1 to 12, wherein the surface roughness is 0.6 nm or less.

[0026] 14. The oxide semiconductor film according to any one of items 1 to 13, having a hydrogen concentration of 1 × 10⁻⁶ in a measurement performed according to secondary ion mass spectrometry (SIMS). 18 atoms / cm 3 Above and 5×10 22 atoms / cm 3 The following areas.

[0027] 15. The oxide semiconductor film according to any one of items 1 to 14, wherein the film is formed by atomic layer deposition (ALD).

[0028] 16. An oxide semiconductor film having a manganese perforate structure and having a {100} orientation relative to a crystal plane of an underlying layer surface. The atomic ratio of In in the oxide semiconductor film relative to all metal elements ([In] / ([In]+[all metal elements other than In])×100) is 80 at% or more.

[0029] 17. The oxide semiconductor film according to item 16, wherein the orientation ratio OR of the (222) plane relative to the (400) plane is... （222） / （400） It is above 0.01 and below 0.80.

[0030] 18. The oxide semiconductor film according to claim 17, further comprising Ga.

[0031] 19. A transistor having on a substrate a layer made of an oxide semiconductor film as described in any one of claims 1 to 18, an insulating film layer, and an electrode.

[0032] 20. The transistor according to item 19 is of the bottom-gate top-contact type.

[0033] 21. The transistor according to item 19 is of the top-gate top-contact type.

[0034] 22. The transistor according to any one of items 19 to 21, wherein the insulating film layer is mainly composed of hafnium oxide.

[0035] 23. The transistor according to any one of items 19 to 21, wherein the insulating film layer is mainly composed of silicon oxide.

[0036] 24. The transistor according to any one of items 19 to 21, wherein the insulating film layer is mainly composed of aluminum oxide.

[0037] 25. The transistor according to any one of items 19 to 24, wherein the electrode is composed primarily of titanium nitride.

[0038] 26. The transistor according to any one of items 19 to 24, wherein the electrode is composed primarily of tungsten.

[0039] 27. A semiconductor device comprising the transistor described in any one of claims 19 to 26.

[0040] 28. An electronic circuit comprising the semiconductor device described in item 27.

[0041] 29. An electrical device, electronic device, vehicle or power unit comprising the electronic circuitry described in item 28.

[0042] 30. A method for manufacturing an oxide semiconductor film according to any one of items 1 to 18, comprising a step of forming the film using an indium-containing precursor by atomic layer deposition (ALD).

[0043] 31. The method according to item 30, wherein triethylindium is used as the indium-containing precursor.

[0044] 32. The method according to item 31 also uses a gallium-containing precursor.

[0045] 33. The method according to any one of items 30 to 32, wherein H2O plasma is used as an oxidant in the film-forming process.

[0046] 34. The method according to any one of items 30 to 32, wherein O2 plasma is used as an oxidant in the film-forming process.

[0047] 35. The method according to any one of items 30 to 34, wherein the oxide semiconductor film is an indium oxide film.

[0048] 36. The method according to any one of items 30 to 35, wherein the container containing the indium-containing precursor is heated in the range of 75 to 125°C.

[0049] According to the present invention, it is possible to provide an oxide semiconductor film with low carrier concentration and high Hall mobility. Attached Figure Description

[0050]

【 Figure 1 The graph shows the amount of oxide semiconductor film grown in the ALD process when H2O plasma or O2 plasma is used and the substrate temperature is changed.

[0051]

【 Figure 2A The diagram above is a schematic representation of the structure of a bottom-gate bottom-contact (BGBC) transistor.

[0052]

【 Figure 2B The diagram above is a schematic representation of the structure of a bottom-gate top-contact (BGTC) transistor.

[0053]

【 Figure 2C The diagram above is a schematic representation of the structure of a top-gate bottom-contact (TGBC) transistor.

[0054]

【 Figure 2D The diagram above is a schematic representation of the structure of a top-gate top-contact (TGTC) transistor.

[0055]

【 Figure 3A The image shown is a schematic diagram of a cross-section of a three-dimensional vertical channel transistor memory.

[0056]

【 Figure 3B The diagram shows a schematic representation of the film formation result of an oxide semiconductor film when attempting to form a three-dimensional vertical channel layer by sputtering.

[0057]

【 Figure 3C The diagram above is a schematic representation of the film formation result of an oxide semiconductor film when a three-dimensional channel layer is formed using the ALD method.

[0058]

【 Figure 4 The figure represents a simulated spectrum with the {100} orientation.

[0059]

【 Figure 5 [Image 1] is a diagram showing an example of an electron beam diffraction spot obtained from an oxide semiconductor film according to a scheme of the present invention.

[0060]

【 Figure 6 The symbol represents the carrier concentration [N] when O2 plasma and H2O plasma are used in a 1:1 ratio in the ALD process. e ( / cm) 3 )] and Hall mobility [μ (cm) 2 A diagram showing the relationship between / Vs).

[0061]

【 Figure 7 The graph shows the relationship between carrier concentration and Hall mobility when using O2 plasma and H2O plasma at a ratio of 3:1 or 5:1 in the ALD method.

[0062]

【 Figure 8 The graph shows the relationship between carrier concentration and Hall mobility in the ALD process for 6 cycles with H2O plasma followed by 170 cycles with O2 plasma, and for 30 cycles with H2O plasma followed by 130 cycles with O2 plasma. Detailed Implementation

[0063] In this specification, "x~y" represents a numerical range "above x and below y". The upper and lower limits of the numerical range can be combined arbitrarily. Furthermore, solutions obtained by combining two or more of the various embodiments of the present invention described below also belong to the present invention.

[0064] In this specification and other materials, the terms "membrane" or "thin film" and "layer" may be used interchangeably in certain circumstances.

[0065] In this specification, "electrical connection" includes connections made through "objects that have a certain electrical function." Here, there are no particular limitations on what constitutes an "object that has a certain electrical function," as long as it can transmit electrical signals between the connected objects. For example, an "object that has a certain electrical function" includes electrodes, wiring, switching elements (transistors, etc.), resistive elements, inductors, capacitors, and other components with various other functions.

[0066] In this specification and other materials, the functions of the source and drain of a transistor may sometimes be interchanged when transistors of different polarities are used or when the current direction changes during circuit operation. Therefore, the terms source and drain may be used interchangeably in this specification and other materials.

[0067] 1. Oxide semiconductor film The oxide semiconductor film of one aspect of the present invention is characterized by having a ferromanganese oxide structure and having a {100} orientation relative to the crystal plane of the underlying surface.

[0068] By aligning the aforementioned crystal planes with a {100} orientation, the carrier concentration can be reduced, resulting in high Hall mobility. Because the {100} plane of indium oxide has a high surface energy, its reactivity during film formation is easily increased.

[0069] The statement that "the crystal plane of the underlying surface in contact with the oxide semiconductor film has a {100} orientation" was confirmed by the method described in the examples.

[0070] "Having a {100} orientation relative to the crystal plane of the underlying surface" specifically means that, in the XRD measurements described in the examples, the (400) orientation of the indium oxide ferromanganese structure is the dominant orientation.

[0071] In one embodiment, if the diffraction intensity ratio I(222) / I(400) of the (222) peak intensity (I(222)) to the (400) peak intensity (I(400)) in the X-ray diffraction pattern of the oxide semiconductor film in X-ray diffraction is less than 10 / 3, then the (400) orientation is dominant.

[0072] It should be noted that {100} is a crystallographic representation of an equivalent crystal plane. In the indium oxide ferromanganese oxide structure, the following are the equivalent crystal planes.

[0073]

Number 1

[0074] In addition, although the (100) face is used as an example, the (100) face is parallel to the (200) face, (300) face, (400) face, and (n00) face (n = integer), which means that they have the same orientation.

[0075] In order to achieve a "{100} orientation of the crystal plane relative to the lower surface in contact with the oxide semiconductor film", it is sufficient to use water plasma for film formation.

[0076] In one embodiment, the oxide semiconductor film of this scheme has a carbon concentration of 1 × 10⁻⁶ in measurements performed according to secondary ion mass spectrometry (SIMS). 18 atoms / cm 3 Above and 5×10 22 atoms / cm 3 The following areas.

[0077] In one embodiment, the measurement performed according to secondary ion mass spectrometry (SIMS) has a hydrogen concentration of 1 × 10⁻⁶. 18 atoms / cm 3 Above and 5×10 22 atoms / cm 3 The following areas.

[0078] The carbon and hydrogen concentration measurements by SIMS were performed under the conditions described in the examples.

[0079] Here, when the oxide semiconductor film of this solution "has" the aforementioned specified carbon and hydrogen concentrations, it means that the carbon and hydrogen concentrations at a certain point (location) in the oxide semiconductor film, as measured by SIMS as described later, only need to meet the aforementioned ranges. Therefore, it is not necessary to meet the aforementioned carbon and hydrogen concentrations throughout the entire oxide semiconductor film.

[0080] The above carbon concentration only needs to be 1×10 18 atoms / cm 3 That's sufficient; the lower limit can also be 5 × 10. 18 atoms / cm 3 8×10 18 atoms / cm 3 1×10 19 atoms / cm 3 3×10 19 atoms / cm 3 5×10 19 atoms / cm 3 1×10 20 atoms / cm 3 5×10 20 atoms / cm 3 or 1×10 21 atoms / cm 3 .

[0081] The above carbon concentration only needs to be 5×10 22 atoms / cm 3 The following is acceptable; the upper limit can also be 1×10. 22 atoms / cm 3 5×10 21 atoms / cm 3 3×10 21 atoms / cm 3 1×10 21 atoms / cm 3 5×10 20 atoms / cm 3 3×10 20 atoms / cm 3 1×10 20 atoms / cm 3 5×10 19 atoms / cm 3 or 1×10 19 atoms / cm 3 .

[0082] The above hydrogen concentration only needs to be 1×1018 atoms / cm 3 That's sufficient; the lower limit can also be 5 × 10. 18 atoms / cm 3 1×10 19 atoms / cm 3 5×10 19 atoms / cm 3 1×10 20 atoms / cm 3 Or 5×10 20 atoms / cm 3 .

[0083] The above hydrogen concentration only needs to be 5×10 22 atoms / cm 3 The following is acceptable; the upper limit can also be 1×10. 22 atoms / cm 3 5×10 21 atoms / cm 3 2×10 21 atoms / cm 3 1×10 21 atoms / cm 3 5×10 20 atoms / cm 3 or 1×10 20 atoms / cm 3 .

[0084] To set the carbon concentration in the oxide semiconductor film of this scheme to 1×10 18 atoms / cm 3 Above and 5×10 22 atoms / cm 3 In the case of ALD, controlling the substrate temperature and the type or amount of oxidant during film deposition is sufficient. In the case of sputtering, controlling the carbon content of the sputtering target used is sufficient.

[0085] To set the hydrogen concentration in the oxide semiconductor film of this scheme to 1×10 18 atoms / cm 3 Above and 5×10 22 atoms / cm 3 In the case of ALD (Alternating Current Deposition), the substrate temperature and the type or amount of oxidant during film formation can be controlled. In the case of sputtering, the amount of water introduced during sputtering can be controlled.

[0086] The oxide semiconductor film constituting this solution is not particularly limited, as long as it is an oxide capable of functioning as a semiconductor. Specifically, metal oxides can be used, and the metals used can be In, Ga, Zn, Al, Sn, etc.

[0087] Specific examples of metal oxides include indium oxide (IO), indium gallium oxide (IGO), indium gallium zinc oxide (IGZO), indium gallium aluminum oxide (IGAO), indium gallium tin zinc oxide (IGTZO), and indium tin zinc oxide (ITZO).

[0088] In one embodiment, the oxide semiconductor film of this solution contains indium oxide as the main component.

[0089] "Containing indium oxide as a main component" means that more than 50% by mass of the oxide semiconductor in the oxide semiconductor film constituting this solution is indium oxide. The indium oxide can be 55% or more by mass, 60% or more by mass, 70% or more by mass, 80% or more by mass, 90% or more by mass, 95% or more by mass, 97% or more by mass, 98% or more by mass, or 99% or more by mass, or it can be 100% by mass.

[0090] In one embodiment, the oxide semiconductor film of this solution further comprises Ga.

[0091] In one embodiment, the atomic ratio of Ga to all metal elements in the oxide semiconductor film of this scheme ([Ga] / ([Ga]+[all metal elements other than Ga])×100) is 30at% or less, or it may be 25at% or less, 22at% or less, or 20at% or less.

[0092] In one embodiment, the oxide semiconductor film of this solution further comprises one or more additive elements selected from B, Al, Si, Sc, Zn, Ce, Y, Zr, Sn, Sm, Hf, Ta, and Yb.

[0093] In one embodiment, the total amount of added elements contained in the oxide semiconductor film of this solution is 10 at% or less, or 8 at% or less, 5 at% or less, or 3 at% or less, relative to the atomic ratio of all metal elements ([total amount of added elements] / ([total amount of added elements]+[all metal elements other than added elements])×100).

[0094] In one embodiment, at least one of the X-ray diffraction pattern in X-ray diffraction (XRD) and the electron beam diffraction spot in electron beam diffraction shows a ferromanganese structure. The presence or absence of a ferromanganese structure is determined by obtaining the X-ray diffraction pattern or the electron beam diffraction spot using the methods and conditions described in the examples.

[0095] Regarding the oxide semiconductor film of this scheme, "at least one of the X-ray diffraction pattern in X-ray diffraction (XRD) and the electron beam diffraction spot in electron beam diffraction (ED) shows a ferromanganese structure" means, for example, even if the X-ray diffraction pattern does not show a ferromanganese structure, as long as the electron beam diffraction spot shows a ferromanganese structure, it is determined to have a ferromanganese structure.

[0096] Here, the XRD method is broadly divided into in-plane measurement and out-of-plane measurement, but out-of-plane measurement is used in this specification.

[0097] In the ferromanganese-type crystal planes described in this specification, the (001) plane includes the (001) plane and its equivalents, the (100) plane and the (010) plane, collectively referred to as {100}. Similarly, the (101) plane includes the (101) plane and its equivalents, the (110) plane and the (011) plane, collectively referred to as {110}. Furthermore, the (111) plane can also be represented as {111}. Moreover, in each plane, "1" can also be "-1", and is considered as a plane equivalent to each plane.

[0098] It should be noted that, as crystal planes, besides {100}, there are also {h00} (where h is a natural number other than 1), {hk0} (where h ≠ k, and h and k are natural numbers), {hhl} (where h ≠ l, and h and l are natural numbers), and {hkl} (where h ≠ k ≠ l, and h, k, and l are natural numbers). It should also be noted that, in this specification, if h, k, and l within {} have common divisors, the plane obtained by dividing by their greatest common divisor can be treated as an equivalent plane.

[0099] When an oxide semiconductor film is crystalline, peaks appear at predetermined diffraction angles (2θ) in out-of-plane diffraction patterns. For example, conventional crystalline oxide semiconductor films containing more than 50% indium and having a manganese oxide-type structure exhibit peaks at diffraction angles near 31° and 44° in their diffraction patterns. The peak at the 31° diffraction angle is attributed to the (222) plane of the manganese oxide-type structure (equivalent to {111}). The peak at the 44° diffraction angle is attributed to the (422) plane of the manganese oxide-type structure (equivalent to {211}). Furthermore, the peak intensity at the 31° diffraction angle is significantly greater than that at the 44° diffraction angle. This indicates the presence of a large number of crystals with {111} planes in the direction parallel to the surface of the oxide semiconductor film.

[0100] It should be noted that the diffraction angles of the diffraction patterns of oxide semiconductor films can vary depending on the composition of the metal elements contained in the oxide semiconductor film or the fabrication conditions of the oxide semiconductor film. Therefore, in this specification, the vicinity of the diffraction angle peak includes a range of ±2°.

[0101] The assignment of diffraction patterns for each plane is discussed more specifically using the indium oxide powder XRD database. In this specification, indium oxide powder XRD results recorded in the powder diffraction database (JCPDS Card No. 06-0416) are used. The diffraction from plane (222) occurs at 2θ = 30.580° with a relative intensity of 100. The diffraction from plane (400) is a peak at 2θ = 35.466° with a relative intensity of 30. The diffraction from plane (440) is a peak at 2θ = 51.037° with a relative intensity of 35. The diffraction from plane (662) is a peak at 2θ = 60.676° with a relative intensity of 25.

[0102] Here, in XRD measurements, a polycrystalline oxide semiconductor film with a manganese oxide structure refers to the observation of at least two diffraction peaks originating from the aforementioned main specific planes (222), (400), (440), and (662). Furthermore, in electron beam diffraction measurements, a polycrystalline oxide semiconductor film with a manganese oxide structure refers to the observation of peaks corresponding to WO202363352 on the same plane of the film. Figure 4 Two or more diffraction peaks of (111), (100), (110) or {111}, {100}, {110} in the diffraction pattern recorded in the document.

[0103] Here, in discussing the orientation of a specific facet of an oxide semiconductor film, the peak intensity I of the diffraction pattern of the specific facet of the oxide semiconductor film actually measured in XRD measurements is given. （hkl） Using relative intensity R （hkl） The normalized values ​​are compared. For example, in the case where the (222) face is preferentially oriented relative to the (400) face, I （222） / 100 becomes more than I （400） / 35 is a large value.

[0104] Furthermore, the orientation rate OR of two specific faces can be defined as the ratio of I... （hkl） / R （hkl） Use I （hkl）‘ / R （hkl）’ The value obtained by division. For example, the orientation rate OR of the (222) plane relative to the (400) plane. （222） / （400） For I （222） / 100) / (I （400） ( / 35). Furthermore, in this specification, the orientation ratios OR of the two specific faces can be consistent with the area ratios of the specific faces directly observed by electron beam diffraction or electron beam backscatter diffraction (EBSD). Correction factors can be calculated to improve accuracy by comparing the orientation ratios from XRD measurements with those from electron beam diffraction measurements or EBSD.

[0105] It should be noted that, regarding oxide semiconductor films with a ferromanganese oxide structure, OR （222） / （400） It can also be expressed as OR （111） / （100） It can also be represented as OR {111} / {100} The OR values ​​used in this specification are based on XRD measurement results.

[0106] In this embodiment, the orientation rate OR （222） / （400） The value is 1.00 or less, preferably 0.00 to 0.90 or less, more preferably 0.01 to 0.80 or less, further preferably 0.02 to 0.70 or less, and even more preferably 0.03 to 0.60 or less. Orientation rate OR （222） / （400） Within the above range, it can be above 0.05, above 0.10, above 0.15, or above 0.20, or below 0.50, below 0.45, below 0.40, below 0.35, or below 0.30. This is achieved by ORing the orientation rate. （222） / （400） Within the aforementioned range, there is a tendency to further reduce the carrier concentration and obtain a higher Hall mobility.

[0107] The oxide semiconductor film in this embodiment is a crystalline oxide semiconductor film. Furthermore, the oxide semiconductor film involved in this embodiment is preferably composed primarily of In. Being primarily composed of In means that the atomic ratio of In relative to all metal elements in the oxide semiconductor film ([In] / ([In]+[all metal elements other than In])×100) (atomic %: at%) is 50 at% or more. The atomic ratio of In is preferably 62 at% or more, more preferably 70 at% or more, more preferably 80 at% or more, and even more preferably 85 at% or more. If 50 at% or more of the total number of atoms of the metal elements constituting the oxide semiconductor film is In, then when the stacked structure involved in this embodiment is applied to a transistor, a sufficiently high mobility can be achieved.

[0108] "The X-ray diffraction pattern in X-ray diffraction or the electron beam diffraction spots in electron beam diffraction show an argentite structure" means that the argentite structure must be shown in at least one of the X-ray diffraction pattern and the electron beam diffraction spots.

[0109] The oxide semiconductor film of this scheme exhibits a ferromanganese structure, which can achieve the effect of reduced carrier concentration and high Hall mobility.

[0110] The oxide semiconductor film of this scheme, which contains indium oxide as the main component and has a ferromanganese structure, can contain any other elements within a range that can maintain the ferromanganese structure.

[0111] In addition to In, the oxide semiconductor film of this scheme may also contain one or more elements selected from the group consisting of H, B, C, N, O, F, Mg, Al, Si, O, S, Cl, Ar, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Sn, Sb, Cs, Ba, Ln, Hf, Ta, W, Re, Os, Ir, Pt, Au, Pb and Bi.

[0112] In this embodiment, the oxide semiconductor film may be substantially composed only of elements selected from In, Mg, Al, Si, Zn, Ga, Mo, Sn, Ln (lanthanides) and O. Here, "substantially" means that, within the scope of producing the effects of the present invention resulting from the combination of the above-mentioned In, Mg, Al, Si, Zn, Ga, Mo, Sn, Ln and O, the oxide semiconductor film of this embodiment may also contain other components.

[0113] In this embodiment, a more preferred first method for the oxide semiconductor film is that the metal elements are composed of In and Ga, and the atomic ratio satisfies the following formula (11).

[0114] [Ga] / ([In]+[Ga])<22at%…(11) It should be noted that metallic elements can inevitably contain impurities, and therefore, in addition to O, they can also contain F or H. By setting the composition within the above range, the In ratio increases, allowing Ga to be substituted into In sites and crystallized into a ferromanganese structure at an annealing temperature of around 300°C. Furthermore, by adding Ga, which has a strong affinity for oxygen, oxygen vacancies after annealing can be suppressed, enabling the formation of a semiconductor-stable film.

[0115] A more preferred second aspect of the oxide semiconductor film of this scheme is that, as a metal element, it is composed of In and one or more elements X selected from B, Al, Sc, Mg, Zn, Ti, Y, Zr, Mo, Sn, Hf, W, Nb, Ta, Ge, Si, La, Ce, Pr, Nd, Sm, Dy, Ho, Er, Tm, Yb and Lu. When the metal element other than In is set as X, the atomic ratio satisfies the following formula (12).

[0116] [X] / ([In]+[X])<15at%…(12) It should be noted that metallic elements can inevitably contain impurities, and therefore, in addition to O, they can also contain F or H. By setting the composition within the above range, the In ratio increases, allowing crystallization at an annealing temperature of around 300°C into a ferromanganese structure where X substitutes for In sites. Furthermore, by adding element X, which has a strong affinity for oxygen, oxygen vacancies after annealing can be suppressed, enabling the formation of a semiconductor-stable film.

[0117] The preferred third aspect of the oxide semiconductor film of this scheme is as follows: as a metal element, it is composed of In, Ga, and one or more elements X selected from B, Al, Sc, Mg, Zn, Ti, Y, Zr, Mo, Sn, Hf, W, Nb, Ta, Ge, Si, La, Ce, Pr, Nd, Sm, Dy, Ho, Er, Tm, Yb and Lu. When metal elements other than In and Ga are set as additive elements X, the atomic ratio satisfies the following formulas (13) and (14).

[0118] [Ga] / ([In]+[Ga]+[X])<22.5at%…(13) [X] / ([In]+[Ga]+[X])<8.0at%…(14) It should be noted that metallic elements can contain unavoidable impurities, and therefore, in addition to O, they can also contain F or H.

[0119] By setting the composition within the aforementioned range, the In ratio increases, enabling crystallization at an annealing temperature of approximately 300°C into a ferromanganese structure where Ga replaces In sites. Furthermore, by adding an additive element X, which has strong affinity for oxygen, oxygen vacancies after annealing can be further suppressed, resulting in a semiconductor-stable film.

[0120] The preferred fourth aspect of the oxide semiconductor film of this scheme is as follows: as a metal element, it is composed of In, Sn, and one or more elements X selected from B, Al, Sc, Mg, Zn, Ti, Y, Zr, Mo, Hf, W, Nb, Ta, Ge, Si, La, Ce, Pr, Nd, Sm, Dy, Ho, Er, Tm, Yb and Lu. When metal elements other than In and Sn are set as element X, the atomic ratio satisfies the following formulas (15) and (16).

[0121] [Sn] / ([In]+[Sn]+[X])<20at%…(15) [X] / ([In]+[Sn]+[X])<8.0at%…(16) It should be noted that metallic elements can contain unavoidable impurities, and therefore, in addition to O, they can also contain F or H.

[0122] By setting the composition range to this extent, the In ratio increases, allowing crystallization into a sinenite structure where Sn substitutes for In sites, even under low-temperature annealing such as 300°C. Sn has a large ionic radius and significant orbital overlap with In, thus maintaining high mobility. Furthermore, by adding an additive element X, which has strong binding affinity to oxygen, oxygen vacancies after annealing can be further suppressed, enabling the formation of a semiconductor-stable film.

[0123] The fifth preferred embodiment of the oxide semiconductor film of this scheme is as follows: as a metal element, it is composed of In, Zn, and one or more elements X selected from B, Al, Sc, Mg, Ti, Y, Zr, Mo, Hf, W, Nb, Ta, Ge, Si, La, Ce, Pr, Nd, Sm, Dy, Ho, Er, Tm, Yb and Lu. When metal elements other than In and Zn are set as element X, the atomic ratio satisfies the following formulas (17) and (18).

[0124] [Zn] / ([In]+[Zn]+[X])<12at%…(17) [X] / ([In]+[Zn]+[X])<8.0at%…(18) It should be noted that metallic elements can contain unavoidable impurities, and therefore, in addition to O, they can also contain F or H.

[0125] By setting the composition within the aforementioned range, the In ratio increases, allowing crystallization at an annealing temperature of approximately 300°C into a ferromanganese structure where Zn substitutes for In sites. Adding Zn enables the newly formed film to be amorphous, allowing for residue-free processing during acid-based semiconductor patterning in the fabrication of transistors and other semiconductor devices. Furthermore, by adding an element X with strong oxygen-binding affinity, oxygen vacancies after annealing can be suppressed, resulting in a semiconductor-stable film.

[0126] In one embodiment, the oxide semiconductor film of this solution comprises a trivalent metal. Ga and Al are preferred as the trivalent metal, with Ga being particularly preferred.

[0127] Furthermore, in one embodiment, the oxide semiconductor film of this solution does not contain divalent elements such as zinc, magnesium, copper, cobalt, nickel, calcium, and strontium.

[0128] In one embodiment, the carrier concentration of the oxide semiconductor film in this scheme is 1×10⁻⁶ at room temperature. 19 cm -3 the following.

[0129] If the carrier concentration at room temperature is 1×10 19 cm -3The following allows it to function fully as a semiconductor film. The preferred carrier concentration is 5 × 10⁻⁶. 18 cm ―3 Hereinafter, 1×10 is more preferred. 18 cm ―3 the following.

[0130] The carrier concentration of an oxide semiconductor film is an indicator of the threshold voltage that controls transistor characteristics. If the carrier concentration is 1 × 10⁻⁶... 19 cm -3 Therefore, good turn-off operation can be confirmed when manufacturing transistors.

[0131] The carrier concentration of the oxide semiconductor film was measured using the method described in the examples.

[0132] In one embodiment, the Hall mobility of the oxide semiconductor film of this solution is 30 cm⁻¹. 2 / Vs or more. Preferably 40cm. 2 / Vs or more, preferably 50cm 2 / Vs or higher, further preferably 80cm 2 / Vs and above.

[0133] The Hall mobility of oxide semiconductor films serves as an indicator of the field-effect mobility of transistor characteristics. If the Hall mobility is 30 cm⁻¹... 2 If the voltage is above / Vs, then the transistor can operate well.

[0134] The Hall mobility of the oxide semiconductor film was measured using the method described in the examples.

[0135] In one embodiment, the oxide semiconductor film has a thickness of less than 20 nm. The thickness of the oxide semiconductor film can be measured by X-ray reflectivity measurement or cross-sectional TEM. Specifically, the measurement is performed using the method described in the examples. The thickness measurement by cross-sectional TEM is performed based on cross-sectional TEM observation images.

[0136] When the oxide semiconductor film of this solution is used for various memory applications, such as fine-grained applications, the smaller the film thickness, the better, preferably 19 nm or less, more preferably 18 nm or less, 17 nm or less, 16 nm or less, 15 nm or less, 12 nm or less, 10 nm or less, 8 nm or less, or 5 nm or less.

[0137] In one embodiment, the surface roughness of the oxide semiconductor film of this solution is below 0.6 nm. Unlike sputtering, in the case of film deposition by ALD, since each atomic layer is deposited sequentially, the surface of the underlying layer is almost faithfully followed. Furthermore, the surface roughness Ra decreases as the resulting film thickness decreases and increases as the film thickness increases.

[0138] The surface roughness Ra of the oxide semiconductor film in this scheme varies depending on the film thickness, but is preferably below 0.5 nm, more preferably below 0.4 nm, and even more preferably below 0.3 nm.

[0139] The surface roughness Ra of the oxide semiconductor film was measured using the method described in the examples.

[0140] <Definition and Measurement Methods of Film Thickness and Surface Roughness> Film thickness and surface roughness can be measured using cross-sectional TEM. The baseline for film thickness and surface roughness does not necessarily need to be parallel to the supporting substrate, as long as it is parallel to the lower layer. The region where indium constitutes 50% or more of the total metal composition is defined as the oxide semiconductor film, and its film thickness is the distance between the upper and lower interfaces of this region. Furthermore, if the upper layer is atmospheric, the upper interface can be defined as the surface; if the upper and lower layers are not parallel, the film thickness can be defined as the distance from the intersection of a perpendicular line drawn from the lower layer and the upper layer. Preferably, the film thickness is the average value obtained from three or more thin-film cross-sectional TEM samples. The film thickness in each cross-sectional TEM sample is preferably obtained from an image magnified to 10x to 100x the film thickness at the lower layer interface perpendicular to the film thickness direction.

[0141] Regarding surface roughness, the unevenness of the interface between the oxide semiconductor film and the upper side is traced, and the surface roughness is determined from the cross-sectional TEM image based on the tracing line according to the method for calculating the arithmetic mean height Ra as specified in JIS B0601-2001. The cross-sectional TEM image is preferably obtained at a magnification that has at least five maxima when plotting the tracing line of the interface between the noble metal oxide layer and the metal oxide semiconductor, and that the difference between adjacent maxima and minima can be clearly determined.

[0142] The oxide semiconductor film of this scheme is not particularly limited in its manufacturing method as long as it has the above-mentioned ferromanganese oxide structure and has a {100} orientation relative to the crystal plane of the underlying surface. However, in one embodiment, it is an oxide semiconductor film formed by atomic layer deposition (ALD). The manufacturing method of the oxide semiconductor film by ALD will be described later.

[0143] 2. Manufacturing method of oxide semiconductor film The method for manufacturing an oxide semiconductor film according to one aspect of the present invention (hereinafter sometimes referred to as the method of this aspect) is a method for manufacturing the oxide semiconductor film involved in the above-mentioned aspect of the present invention, characterized in that it includes a step of forming a film using an indium-containing precursor by atomic layer deposition (ALD).

[0144] Atomic layer deposition (ALD) is a thin film formation method in which a raw material (sometimes called a precursor) containing the metal elements constituting the oxide semiconductor film and an oxidant are alternately exposed to the substrate surface as one cycle. One atomic layer is formed by one cycle, and the cycle is repeated until the desired film thickness is achieved, thereby forming an oxide semiconductor film. The specific steps of ALD are described later.

[0145] According to ALD, ultrathin films of several nanometers can be deposited through precisely controlled methods. Therefore, ALD is also a suitable film deposition method for manufacturing oxide semiconductor films such as the three-dimensional vertical channel transistor memory developed in recent years.

[0146] Typically, one atomic layer deposition cycle of ALD consists of the following four steps.

[0147] (1) The precursor is vaporized in a container containing the precursor as a raw material and introduced into a chamber. A predetermined system pressure is applied and the precursor reacts with OH groups on the substrate surface or film surface for a predetermined time to adsorb monomolecules. When the vapor pressure of the precursor is low, the container containing the precursor can be heated to promote vaporization; when the vapor pressure of the precursor is high, the container containing the precursor can be cooled to suppress vaporization.

[0148] (2) By purging with inert gas, unreacted raw materials and byproduct gas are removed from the chamber, and an atomic layer is deposited.

[0149] (3) The reactive gas is introduced into the chamber and the metal of the precursor is oxidized by heat or plasma.

[0150] (4) Remove unreacted oxidant and byproduct gas by purging with inert gas.

[0151] After step (4), return to step (1) and repeat steps (1) to (4) until the desired film thickness is achieved.

[0152] In the method of this scheme, known ALD devices can be used. Specifically, for example, devices capable of bubbling and supplying precursors, and devices having a vaporization chamber can be used. In addition, devices capable of plasma treatment of reactive gases (oxidants) can be used. It should be noted that it is not limited to single-plate devices with film-forming chambers, but also devices that utilize batch furnaces and can process multiple plates simultaneously can be used.

[0153] Examples of ALD precursors include organometallic compounds (e.g., AlMe3), metal hydrides (e.g., AsH3), metal alkoxides (e.g., Ti(OCHMe2)4), metal amides (e.g., Ti(NMe2)4), β-diketone salts (e.g., Co(acac)2), metallocenes (e.g., MgCp2), and metal amidine salts.

[0154] As metal compounds used as ALD precursors, there are a wide variety of commercially available compounds. The choice is to select a precursor and oxidant that can form the target oxide semiconductor film.

[0155] Examples of indium-containing precursors used for depositing indium oxide (In2O3) layers via ALD include InCl3, TMIn (trimethyl indium), TEIn (triethyl indium), InCp (cyclopentadienyl indium(I)), InEtCp (ethylcyclopentadienylindium(I)), In(acac)3 (indium acetylacetonate), In(tmhd)3 (indium 2,2,6,6-tetramethyl-3,5-heptanedionate), In[( iPrN)2CNR2]3(R=Me) (indium-tris-guanidinates: triguanidinate indium), Et2InN(TMS)2(diethyl[bis-(trimethylsilyl)amido]indium: diethyl[bis(trimethylsilyl)amino]indium(III)), INCA(diethyl[1,1,1-trimethyl-N-(trimethylsilyl)silanaminato]indium: diethyl[1,1,1-trimethyl-N-(trimethylsilyl)silaneamino]indium), DADI([3-(dimethylamino)propyl]dimethyl indium: [3-(dimethylamino)propyl]dimethylindium), In(dmamp)3 ((1-dimethylamino-2-methyl-2-propoxy)indium: tris(1-dimethylamino-2-methyl-2-propoxy)indium(III)), Me2In(EDPA) (dimethyl(N-ethoxy-2,2-dimethylpropanamido)indium: dimethyl(N-ethoxy-2,2-dimethylpropanamido)indium), tris(N,N'-diisopropylacetamidinato)indium(III) (tris(N,N'-diisopropylacetamidinato)indium(III)), etc.

[0156] These ALD precursors can be used individually or in combination of two or more.

[0157] Furthermore, regarding the metal cations constituting the oxide semiconductor film, as long as In is the main component, precursors containing other metal cations as additives can also be used to form the thin film.

[0158] As a precursor, one or more compounds selected from the group consisting of compounds used as organic ligands, such as alcohols, diols, β-diketones, cyclopentadienes, and organic amines, that react with indium or metal cations can be cited.

[0159] Examples of metal cations include lithium, sodium, potassium, magnesium, calcium, strontium, barium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, boron, aluminum, silicon, indium, gallium, germanium, tin, lead, antimony, bismuth, scandium, ruthenium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

[0160] Furthermore, the following compounds can be cited as compounds that coordinate with metal cations containing indium. Additionally, depending on the valence of the central metal, multiple coordination species may coordinate, but these can be the same compound or a combination of multiple different coordination species.

[0161] Examples of alkyl compounds include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, tert-butyl, pentyl, isopentyl, and tert-pentyl.

[0162] Examples of alcohol compounds include methanol, ethanol, propanol, isopropanol, butanol, sec-butanol, isobutanol, tert-butanol, pentanol, isopentanol, tert-pentanol, and other alkyl alcohols; 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-(2-methoxyethoxy)ethanol, 2-methoxy-1-methylethanol, 2-methoxy-1,1-dimethylethanol, 2-ethoxy-1,1-dimethylethanol, 2-isopropoxy-1,1-dimethylethanol, 2-butoxy-1,1-dimethylethanol, 2-(2- Ether alcohols such as methoxyethoxy-1,1-dimethylethanol, 2-propoxy-1,1-diethylethanol, 2-sec-butoxy-1,1-diethylethanol, and 3-methoxy-1,1-dimethylpropanol; and dialkylamino alcohols such as dimethylaminoethanol, ethylmethylaminoethanol, diethylaminoethanol, dimethylamino-2-pentanol, ethylmethylamino-2-pentanol, dimethylamino-2-methyl-2-pentanol, ethylmethylamino-2-methyl-2-pentanol, and diethylamino-2-methyl-2-pentanol.

[0163] Examples of diol compounds include 1,2-ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2,4-hexanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,3-butanediol, 2,4-butanediol, 2,2-diethyl-1,3-butanediol, 2-ethyl-2-butyl-1,3-propanediol, 2,4-pentanediol, 2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 2,4-hexanediol, and 2,4-dimethyl-2,4-pentanediol.

[0164] Examples of β-diketone compounds include acetylacetone, hexane-2,4-diketone, 5-methylhexane-2,4-diketone, heptane-2,4-diketone, 2-methylheptane-3,5-diketone, 5-methylheptane-2,4-diketone, 6-methylheptane-2,4-diketone, 2,2-dimethylheptane-3,5-diketone, 2,6-dimethylheptane-3,5-diketone, 2,2,6-trimethylheptane-3,5-diketone, 2,2,6,6-tetramethylheptane-3,5-diketone, octane-2,4-diketone, 2,2,6-trimethyloctane-3,5-diketone, 2,6-dimethyloctane-3,5-diketone, 2,9-dimethylnonane-4,6-diketone, and 2-methyl-6- Alkyl-substituted β-diketones such as ethyldecane-3,5-dione and 2,2-dimethyl-6-ethyldecane-3,5-dione; fluorinated alkyl β-diketones such as 1,1,1-trifluoropentane-2,4-dione, 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dione, 1,1,1,5,5,5-hexafluoropentane-2,4-dione, and 1,3-diperfluorohexylpropane-1,3-dione; and ether-substituted β-diketones such as 1,1,5,5-tetramethyl-1-methoxyhexane-2,4-dione, 2,2,6,6-tetramethyl-1-methoxyheptane-3,5-dione, and 2,2,6,6-tetramethyl-1-(2-methoxyethoxy)heptane-3,5-dione.

[0165] Examples of cyclopentadiene compounds include cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, propylcyclopentadiene, isopropylcyclopentadiene, butylcyclopentadiene, sec-butylcyclopentadiene, isobutylcyclopentadiene, tert-butylcyclopentadiene, dimethylcyclopentadiene, and tetramethylcyclopentadiene.

[0166] Examples of organic amine compounds include methylamine, ethylamine, propylamine, isopropylamine, butylamine, sec-butylamine, tert-butylamine, isobutylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, ethylmethylamine, propylmethylamine, and isopropylmethylamine.

[0167] Furthermore, for the metal cation, a chloride or fluoride can be coordinated, or it can be a combination of a chloride or fluoride and a compound coordinated to the aforementioned metal cation. Additionally, some or all of the hydrogen in the compound coordinated to the aforementioned metal cation can be replaced with chlorine or fluorine.

[0168] Specifically, examples of gallium-containing precursors include trimethylgallium (TMG), triethylgallium (TEG), triisopropoxygallium (Ga(OCH(CH3)2)3), trimethoxygallium (Ga(OCH3)3), gallium trichloride (GaCl3), gallium dichloride dimethylamide (GaCl2(N(CH3)2)), gallium acetylacetonate (Ga(acac)3), gallium triimide (Ga(NR)3, where R is an organic group), tris(2,2,6,6-tetramethyl-3,5-heptanedionate)gallium (Ga(tmhd)3), cyclopentadienylgallium ethylcyclopentadienyl (GaEcCp), cyclopentadienylgallium (I) (GaCp), and ethylcyclopentadienylgallium (I) (GaEtCp). Among these, at least one selected from the group consisting of trimethylgallium and triethylgallium is preferred as a gallium-containing precursor.

[0169] Among these precursors, trimethylaluminum, trimethylgallium, triethylgallium, dimethylzinc, and diethylzinc, when combined with indium-based precursors, can form excellent oxide semiconductor films. Of these, trimethylgallium and triethylgallium are particularly preferred.

[0170] The precursors formed by the coordination of the aforementioned compounds are well known in the art, and their manufacturing methods are also well known. As an example of a manufacturing method, for instance, when using an alcohol compound as an organic ligand, the precursor can be produced by reacting an inorganic salt or hydrate of the aforementioned metal with an alkali metal alkoxide of the alcohol compound. Examples of inorganic salts or hydrates of the metal include metal halides and nitrates. Examples of alkali metal alkoxides include sodium alkoxides, lithium alkoxides, and potassium alkoxides.

[0171] Examples of oxidants used in ALDs include H2O, O2, O3, O2 plasma, H2O plasma, and hydrogen peroxide (H2O2). These oxidants can be used alone or in combination of two or more.

[0172] When using two or more oxidants, they can be used simultaneously or used individually while varying the types of oxidants. For example, by using both O2 plasma and H2O plasma as oxidants, it is possible to achieve the advantages of high mobility obtained with O2 plasma and reduced carbon concentration or improved mobility stability relative to heat treatment obtained with H2O plasma. By using two or more oxidants, high mobility and low carbon concentration can be adjusted. The appropriate ratio, order of use, and number of cycles of O2 plasma and H2O plasma can be selected according to the target effect.

[0173] Figures 6-8These are graphs showing the relationship between carrier concentration and Hall mobility when using O2 plasma and H2O plasma as oxidants, respectively.

[0174] from Figure 6 As can be seen from the graph, when O2 plasma and H2O plasma are used in a 1:1 ratio (represented by ● in the graph), the Hall mobility is shown to be approximately in the middle between the case of using only O2 plasma (represented by □) and the case of using only H2O plasma (represented by △).

[0175] from Figure 7 As can be seen from the graphs, when using O2 plasma and H2O plasma at a ratio of 3:1 (indicated by ○ in the graph) or at a ratio of 5:1 (indicated by ●), the effect of H2O plasma is suppressed compared to the case of using only O2 plasma (indicated by □), showing behavior close to that of O2 plasma.

[0176] Figure 8 This is a graph showing the relationship between carrier concentration and Hall mobility under the following conditions: 6 cycles with H2O plasma followed by 170 cycles with O2 plasma (represented by ○ in the graph); 30 cycles with H2O plasma followed by 130 cycles with O2 plasma (represented by ●); O2 plasma only (represented by □); and H2O plasma only (represented by △).

[0177] from Figure 8 As shown in the graph, 6 cycles of H2O plasma (○) are close to the case of using only O2 plasma (□), and 30 cycles of H2O plasma (●) can obtain a stable Hall mobility.

[0178] The types of precursors and oxidants are as described above.

[0179] In one embodiment of the method of this scheme, triethylindium is used as an indium-containing precursor.

[0180] In one embodiment, a gallium-containing precursor is used in addition to an indium-containing precursor.

[0181] The pressure in the system (film-forming chamber) in step (1) can be set appropriately according to the type of precursor or the substrate temperature, for example, preferably 1 to 10,000 Pa, more preferably 10 to 1,000 Pa, further preferably 50 to 500 Pa, and particularly preferably 80 to 120 Pa.

[0182] In one embodiment, H2O plasma is used as an oxidant in the film-forming process.

[0183] In one embodiment, O2 plasma is used as an oxidant in the film-forming process.

[0184] By using these oxidants, it is possible to achieve the effect of controlling the electrical properties of oxide semiconductor films in a favorable state.

[0185] In one embodiment, the oxide semiconductor film formed is an indium oxide film.

[0186] To vaporize the precursor, the container holding the precursor can be heated to a temperature that allows for complete vaporization, as needed. When using a precursor with high vapor pressure, the container holding the precursor can be cooled as needed.

[0187] In one embodiment, the container holding the indium-containing precursor (e.g., triethylindium) is heated in the range of 25 to 150°C. The preferred temperature is 50 to 150°C, more preferably 75 to 125°C.

[0188] In the method of this scheme, the substrate temperature during film formation is usually in the range of 50 to 600°C, preferably 85 to 500°C, more preferably 80 to 350°C, and even more preferably 100 to 250°C.

[0189] It should be noted that the growth rate of the oxide semiconductor film per cycle in the ALD process varies depending on the type of precursors and reactive gases used during film deposition, as well as the substrate temperature. The growth rates of the oxide semiconductor film using H2O plasma and O2 plasma with varying substrate temperatures are as follows: Figure 1 As shown. The substrate temperature during film formation is preferably within a range where film growth is stable. From Figure 1 As shown in the charts, when using H2O plasma and O2 plasma, the growth rate is stable and suitable when the substrate temperature during film formation is in the range of 100-150℃.

[0190] The amount of growth per cycle in the ALD process is called Growth per cycle (GPC), which can be calculated, for example, by measuring the thickness of the oxide semiconductor film after 30 repeated ALD cycles. Here, GPC varies depending on the combination of precursor and oxidant and substrate temperature, and will vary even if the substrate type is different.

[0191] Therefore, the number of cycles mentioned above varies depending on several factors, such as the type and combination of precursors and oxidants used, the type of substrate, the substrate temperature during film formation, and the desired film thickness. Therefore, it is appropriate to set the number of cycles taking these factors into account.

[0192] In addition, when using O3 as an oxidant, the substrate temperature during film formation is preferably higher than 100°C, and more preferably 110–250°C, 120–230°C, or 130–220°C.

[0193] Inert gases used to purge unreacted raw materials and unreacted oxidants include, for example, argon and nitrogen. In the method of this scheme, argon or nitrogen is preferred.

[0194] In step (3) above, in the method of this scheme, it is preferable to generate plasma of reactive gas (oxidant).

[0195] 3. Transistor A transistor according to one aspect of the present invention (hereinafter sometimes referred to as the transistor of this aspect) is characterized in that it comprises a layer, an insulating film layer, and an electrode made of the oxide semiconductor film of one aspect of the present invention described above.

[0196] The layer composed of the oxide semiconductor film of the above-mentioned scheme functions as the channel layer in the transistor.

[0197] The transistor of this solution can be any structure as long as it has a layer composed of an oxide semiconductor film according to one aspect of the present invention. Examples include... Figures 2A-2D The various structures shown.

[0198] In one embodiment, the transistor of this solution is a bottom-gate top-contact type.

[0199] In one embodiment, the transistor of this solution is a top-gate top-contact type.

[0200] The insulating film layer can be appropriately selected from materials commonly used as insulating film layers for transistors.

[0201] As the insulating film for functioning as a gate insulating film, one or more insulating films selected from aluminum oxide, magnesium oxide, silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, and tantalum oxide can be used. Alternatively, the insulating film can be a stack of the above materials. It should be noted that the insulating film may contain impurities such as La, N, and Zr. An example of a stacked structure of the insulating film will be described. The insulating film may contain, for example, oxygen, nitrogen, silicon, and hafnium. Specifically, it is preferable to include hafnium oxide and silicon oxide or silicon oxynitride. Hafnium oxide and aluminum oxide have higher relative permittivity than silicon oxide or silicon oxynitride. Therefore, compared to using silicon oxide, when using the same insulating film capacitor, the leakage current caused by tunneling current can be reduced because the film thickness can be increased. That is, a transistor with low turn-off current can be realized. Furthermore, hafnium oxide with a crystalline structure has a higher relative permittivity than hafnium oxide with an amorphous structure. Therefore, hafnium oxide with a crystalline structure is preferred for fabricating transistors with low turn-off current. Examples of crystalline structures include monoclinic and cubic crystal systems, but these are not limiting factors.

[0202] In one embodiment, the insulating film layer is mainly composed of hafnium oxide.

[0203] "Hafnium oxide as the main component" means that more than 50% by mass of the material constituting the insulating film layer is hafnium oxide. The hafnium oxide can be 55% or more by mass, 60% or more by mass, 70% or more by mass, 80% or more by mass, 90% or more by mass, 95% or more by mass, 97% or more by mass, 98% or more by mass, or 99% or more by mass, or it can be 100% by mass.

[0204] By making hafnium oxide the main component of the insulating film, it is possible to improve the dielectric constant of the insulating film.

[0205] In one embodiment, the insulating film layer is mainly composed of silicon oxide.

[0206] In one embodiment, the insulating film layer is mainly composed of aluminum oxide.

[0207] The meaning of "main component" is the same as that of hafnium oxide mentioned above.

[0208] The electrodes are gate electrodes and source / drain electrodes, and can be formed using materials commonly used as electrodes in transistors.

[0209] In one embodiment, the electrode is composed primarily of titanium nitride.

[0210] In one embodiment, the electrode is mainly composed of tungsten.

[0211] By using titanium nitride or tungsten as the main electrode components, it is possible to reduce the parasitic resistance, i.e., the contact resistance, relative to the oxide semiconductor film. Furthermore, by selecting titanium nitride or tungsten as the electrode, film deposition can be performed in an ALD (Alternating Current Discharge).

[0212] (Methods for manufacturing transistors) In addition to forming an oxide semiconductor film through ALD, the transistors of this scheme can be manufactured in the same way as ordinary transistors.

[0213] The formation of the oxide semiconductor film in transistor manufacturing can be carried out using the methods described in the examples. There are no particular limitations on the constituent elements of the transistor other than the channel layer and their fabrication methods; known materials, structures, and fabrication methods can be used.

[0214] Having such Figures 2A-2D The transistors of the various structures shown can be manufactured, for example, as follows.

[0215] For example, a silicon substrate with a thermally oxidized film is used, where the silicon substrate functions as the gate electrode and the thermally oxidized film functions as the gate insulating layer. An oxide semiconductor film layer is formed and patterned on this substrate using the ALD method. This oxide semiconductor film layer functions as the channel layer. Next, a metal film for forming the source and drain electrodes is formed on the oxide semiconductor layer. Then, the source and drain electrodes are formed using a lift-off process, etc., to fabricate a transistor. A protective film can be further formed if necessary.

[0216] <Fabrication process of bottom-gate transistors> The manufacturing method of a transistor substrate with an oxide semiconductor layer will be described using a bottom-gate transistor as an example. A gate electrode is patterned and formed on a substrate made of glass or the like. The gate electrode material is a single layer or a multilayer film composed of materials such as molybdenum, tungsten, aluminum and aluminum alloys, copper and copper alloys, titanium, and platinum. A gate insulating film is formed on the gate electrode. The gate insulating film is typically formed using PE-CVD, such as silicon oxide, silicon nitride, or silicon oxide nitride. The thickness of the gate insulating film is typically 10 to 300 nm. A silicon substrate with a thermal oxide film (substrate resistance less than 0.1 Ωcm) can also be considered as a gate electrode substrate with a gate insulating film. The oxide semiconductor layer on the gate insulating film can be formed by several methods: sputtering, where a sputtering target with the same composition as the oxide semiconductor is formed by DC sputtering or RF sputtering; ALD, where an organometallic material is used as a precursor to form the film; and liquid-phase methods, where a solution of a precursor such as a metal alkoxide, organometallic acid salt, or chloride, or a dispersion of oxide semiconductor nanoparticles is coated and then sintered to form the oxide semiconductor layer. After patterning the oxide semiconductor layer, the source and drain electrodes are formed. The source and drain electrode materials are composed of molybdenum, tungsten, aluminum and aluminum alloys, copper and copper alloys, titanium, platinum, etc., forming a single layer or a multilayer of two or more materials. After forming the source and drain electrode layers, a protective film can be formed. For example, SiO2 or alumina formed by ALD or CVD methods can be used as the protective film. Alternatively, alumina formed by RF sputtering or alumina formed by introducing oxygen during DC sputtering can also be used.

[0217] <The process of annealing transistors that have formed a protective film> Finally, the transistor undergoes annealing. In devices with oxide semiconductors, protective film formation includes film formation via PVD or CVD, patterning via dry or wet etching, and photoresist stripping. However, transistor performance sometimes deteriorates during this process, so annealing is desired to restore performance and adjust carrier concentration. In this invention, by performing annealing at, for example, 250°C or higher, transistor performance can be restored even if it is temporarily reduced during patterning. Particularly, this invention features the characteristic that even when transistor characteristics are significantly reduced, significant performance recovery occurs through annealing in the presence of oxygen. Furthermore, depending on the degree of oxide semiconductor degradation, increasing the annealing temperature or extending the annealing time can restore transistor performance and improve device reliability. The annealing temperature is 250°C to 450°C, preferably 300°C to 400°C. The annealing time is 30 minutes or more, preferably 60 minutes or more. Annealing is preferably performed in the presence of oxygen. However, in annealing in the presence of oxygen, considering the effects of electrode oxidation or discoloration of the protective film of the present invention due to oxidation, it is preferable to perform the annealing at a temperature below 400°C. Annealing can also be performed in a nitrogen atmosphere.

[0218] <Exposure Process> When patterning oxide semiconductor layers, electrodes, and protective films, photoresist is applied and the surface is irradiated with light. The light source used for irradiation can be any light source previously used in patterning methods. Examples of such light sources include high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, xenon lamps, laser diodes, and LEDs. Ultraviolet light, such as g-line, h-line, and i-line, is typically used as the irradiation light. Except for ultra-fine fabrication like semiconductors, light of 360–430 nm (high-pressure mercury lamps) is typically used for patterning from a few μm to tens of μm. In the case of liquid crystal display devices, 430 nm light is often used. While the energy of the irradiation light also depends on the thickness of the light source or the protective film precursor layer, it is typically 20–2000 mJ / cm² in the case of a positive diazonoquinone derivative. 2 Preferably, it is 50–1000 mJ / cm 2 If the energy of the irradiated light is less than 20 mJ / cm 2 Sometimes, sufficient resolution cannot be obtained; conversely, if it exceeds 2000 mJ / cm², it may not achieve adequate resolution. 2 This results in overexposure, which can sometimes cause a halo effect. Additionally, in negative conditions, the concentration is 1–500 mJ / cm². 2 Preferably, it is 10–100 mJ / cm 2 If the energy of the irradiated light is less than 1 mJ / cm 2 If the membrane loss is high, then the membrane loss will be relatively large; conversely, if it is higher than 500 mJ / cm 2If the exposure is too high, it becomes overexposed and sometimes the resolution cannot be achieved.

[0219] To pattern light, a general-purpose photomask can be used. Such a photomask can be chosen arbitrarily from known photomasks. The irradiation environment is not particularly limited; it is typically set to ambient atmosphere (atmosphere) or a nitrogen atmosphere. Furthermore, if a film is formed on the entire surface of a substrate, the entire substrate surface can be irradiated with light. In this invention, the patterned film also includes the case where a film is formed on the entire surface of such a substrate.

[0220] <Post-exposure heating process> After exposure, post-exposure baking can be performed as needed to promote the interpolymer reaction within the film by using the reaction initiator generated at the exposed site. This heating process is not performed to completely harden the photoresist layer, but rather to ensure that only the desired pattern remains on the substrate after development, allowing the rest to be removed by development.

[0221] <Developing Process> After exposure, the photoresist is heated as needed and then developed. Any known developer for developing photosensitive polymer materials or photosensitive siloxane compositions can be used as the developing solution. Preferred developing solutions include aqueous solutions of basic compounds such as tetraalkylammonium hydroxide, choline, alkali metal hydroxides, alkali metal metasilicates (hydrates), alkali metal phosphates (hydrates), ammonia, alkylamines, alkanolamines, and heterocyclic amines, i.e., alkaline developing solutions. A particularly preferred alkaline developing solution is an aqueous solution of TMAH. These alkaline developing solutions may also contain water-soluble organic solvents or surfactants such as methanol and ethanol, as needed. The developing method can be any known method. Specifically, methods such as dipping in the developing solution, static development, spraying, slit coating, capcoating, and spraying can be used. This development process allows the formation of a pattern. After development with the developing solution, rinsing with water is preferred. It should be noted that in this manufacturing method, the drain electrode can also be made to conduct with the transparent electrode (pixel electrode) formed on the protective film through the contact hole formed by development.

[0222] <Post-development irradiation process> When using a positive composition and applying the resulting protective film as a transparent film, light irradiation known as bleaching exposure is preferred. By performing bleaching exposure, unreacted diazonaquinone derivatives remaining in the film are photodecomposed, further improving the film's light transparency. As a method of bleaching exposure, a high-pressure mercury lamp, a low-pressure mercury lamp, or similar device is used, and the entire surface is irradiated at 100–2,000 mJ / cm², depending on the film thickness. 2Approximately (converted from 365nm wavelength exposure). Additionally, in negative conditions, light irradiation activates the curing aids remaining in the film after development, thereby facilitating subsequent heat curing. Depending on the film thickness, irradiation of the entire surface ranges from 100 to 2,000 mJ / cm². 2 Approximately (converted from exposure at a wavelength of 365nm).

[0223] Figure 2D The top-gate-top-contact transistor shown can be manufactured, for example, as follows.

[0224] A first insulating film is formed on a substrate made of glass, silicon, or the like. Examples of materials for the first gate insulating film include single-layer or multilayer films of hafnium oxide, aluminum oxide, silicon oxide, zirconium oxide, tantalum oxide, etc. As one approach, the silicon substrate can be cleaned. After cleaning organic contaminants by heating a liquid containing 1 volume of concentrated sulfuric acid mixed with 0.25 to 1 volume of hydrogen peroxide (SPM solution) to approximately 130°C, followed by cleaning with a 1% hydrofluoric acid aqueous solution, the oxide film on the surface of the silicon substrate can be removed. In one embodiment, heating the silicon substrate to 250°C allows for the formation of a hafnium oxide film via ALD. For example, when forming a hafnium oxide layer using an ALD device, a first raw material gas is used, which is obtained by vaporizing a liquid containing a solvent and a hafnium precursor compound (hafnium alkoxide, tetramethylaminohafnium (TDMAHf), etc., hafnium amide), and a second raw material gas is used, which consists of ozone (O3) and oxygen (O2) as oxidants. When using TDMAHf as the first raw material gas, there is a combination where TDMAHf is supplied from the raw material supply section, and oxygen is supplied from the raw material supply section as the second oxidizing gas. When oxidation is performed by oxygen, the first raw material gas can be oxidized by oxygen plasma. When forming a hafnium oxide film using TDMAHf, the substrate temperature is preferably 100°C to 600°C, more preferably 150°C to 500°C, and more preferably in the range of 200°C to 400°C from the perspective of device damage, and more preferably 250°C.

[0225] Here, the process of forming a metal oxide film on a substrate in the processing container can be performed sequentially in the processing container as follows: a step of supplying a raw material gas containing an organometallic precursor, a step of removing residual gas remaining in the processing container after the step of supplying the raw material gas, a step of supplying an oxidant to oxidize the raw material gas in the processing container, and a step of removing residual gas remaining in the processing container after the step of supplying the oxidant.

[0226] In one embodiment, in order to form a 5nm hafnium oxide film using TDMAHf, the above steps are performed sequentially and repeated for 54 cycles at a substrate temperature of 250°C, using oxygen plasma as the oxidant, with a plasma oxidation time of 20 seconds.

[0227] After the first insulating film is formed, an oxide semiconductor layer can be formed. Indium oxide is suitable as the oxide semiconductor layer, but it is also possible to contain one or more composite oxides selected from gallium oxide, aluminum oxide, tin oxide, zinc oxide, etc.

[0228] When forming an indium oxide layer, sputtering using a ceramic target made of indium oxide can be used, or film formation can be performed using an ALD method utilizing an indium precursor. When using the ALD method, the indium precursor can be one of the compounds mentioned above, or trimethylindium, triethylindium, or cyclopentadienylindium. Here, combinations of oxidants used when triethylindium is used as the feed gas include oxygen, oxygen plasma, ozone, water, and water plasma. The processing temperature of the oxidant is preferably from room temperature to 500°C, more preferably from 50°C to 200°C, and a suitable film formation temperature is from 100°C to 150°C. Assuming that one cycle consists of the step from supplying the raw material gas to the step of supplying the oxidant and then removing the residual gas remaining in the processing container, the film thickness per cycle is called GPC (growth per cycle). The GPC is typically 0.7 ± 0.2 Å / cycle when triethylin is oxidized with water plasma at a substrate temperature of 150°C, 0.6 ± 0.2 Å / cycle when triethylin is oxidized with oxygen plasma at a substrate temperature of 150°C, and 0.5 ± 0.2 Å / cycle when triethylin is oxidized with ozone at a substrate temperature of 150°C.

[0229] The oxide semiconductor layer is preferably formed in the range of 1 Å to 100 nm, more preferably 1 nm to 50 nm. Since the parasitic capacitance of the oxide semiconductor layer becomes a problem in micro-devices, it is preferably 1 nm to 30 nm, more preferably 1 nm to 10 nm, and a suitable range is 1 nm to 5 nm.

[0230] If the oxide semiconductor layer to be formed is amorphous, it is easy to pattern it using wet etching. Referring to the description of the bottom gate above, photoresist can be used for patterning. As an etchant, it is desirable to have an etchant that can dissolve the oxide semiconductor layer but is insoluble in the first insulating film layer, thereby obtaining an etchant with a high selectivity. For example, hydrochloric acid solution, oxalic acid solution, etc., can be used. When there is a high proportion of crystalline components, hydrochloric acid solution is preferred, while when the amorphous components are predominant, oxalic acid solution, which does not easily produce residue, is desirable.

[0231] An oxide semiconductor film of the desired shape is formed by patterning, and its crystallinity can then be improved by a thermal process of annealing. The annealing atmosphere is typically in a vacuum, in nitrogen, or in the atmosphere. In the case of an atmospheric atmosphere, the temperature is preferably 250°C to 600°C, more preferably 300°C to 500°C, and a suitable annealing temperature is 350°C to 450°C. The annealing time is 5 minutes to 2 hours, preferably 30 minutes to 1 hour.

[0232] A second insulating film is then formed. The second insulating film can be formed using the same material and method as the first insulating film. When the second insulating film is used as the gate insulating film of a micro-device, it is desirable to make it as thin as possible so that the capacitance of the gate insulating film does not become a parasitic component. For devices with a device size of 50 nm or less, it is preferably 1 Å or more and 10 nm or less, more preferably 5 Å or more and 5 nm or less, and suitably 10 Å or more and 2 nm or less.

[0233] In one embodiment, hafnium oxide film can be formed using TDMAHf in the same manner as the first insulating film.

[0234] Subsequently, contact holes can be formed on the second insulating film by dry etching. When the second insulating film is hafnium oxide, dry etching can be performed using a mixture of chlorine and argon gas.

[0235] The gate electrode and source / drain electrode can then be formed. The electrodes are composed of single-layer or multi-layer films of materials such as titanium nitride, molybdenum, tungsten, aluminum and aluminum alloys, copper and copper alloys, titanium, and platinum.

[0236] In one embodiment, the gate electrode and the source / drain electrode are formed by sputtering titanium nitride onto a stripping photoresist and then patterning the electrodes.

[0237] Finally, annealing the fabricated top-gate transistor stabilizes the device characteristics. The annealing atmosphere is typically in a vacuum, nitrogen, or atmosphere. In an atmospheric atmosphere, the preferred annealing temperature is 250°C to 600°C, more preferably 300°C to 500°C, and a suitable annealing temperature is 350°C to 450°C. The annealing time is 5 minutes to 2 hours, preferably 30 minutes to 1 hour.

[0238] In one embodiment, the annealing treatment can be performed at 300°C in an argon atmosphere or at 350°C in an atmospheric atmosphere.

[0239] In manufacturing Figure 3A In the case of the aforementioned three-dimensional vertical channel transistor memory, if an attempt is made to form a channel layer composed of an oxide semiconductor film by sputtering, the opening of the lower layer to be covered by the oxide semiconductor film is narrow and cylindrical in the vertical direction. Therefore, as shown in the figure... Figure 3B As shown, oxide semiconductor films can only be formed near the opening of the cylindrical lower layer.

[0240] In contrast, according to the transistor manufacturing method of this scheme, since the oxide semiconductor film layer (channel layer) is formed through ALD, even if the opening of the lower layer is narrow and is a cylindrical shape that is long in the vertical direction, such as Figure 3C As shown, an oxide semiconductor film can also be used to uniformly cover the entire inner surface of the underlying layer, resulting in a highly reliable transistor memory.

[0241] Three-dimensional vertical channel transistors can be such as Figure 3A The three-dimensional vertical channel full-around transistor shown can also be a three-dimensional vertical gate full-around transistor. Other examples of three-dimensional vertical channel transistors include FinFET type or trench gate type transistors.

[0242] 4. Semiconductor devices The semiconductor device of one aspect of the present invention is characterized in that it includes the transistor of one aspect of the present invention described above.

[0243] The semiconductor device of this solution, by incorporating transistors from the aforementioned solution, exhibits excellent electrical characteristics and high reliability.

[0244] In this specification, semiconductor devices include transistors for displays, FETs for memory (DRAM, NAND, ReRAM, FeRAM, MRAM), FETs for logic ICs (CPU, MPU, BEOL, 3D-LSI, CMOS), FETs for sensors (CMOS image sensors), and transistors (MOSFET, power transistor, MESFET), etc.

[0245] 5. Electronic circuits The electronic circuit of one aspect of the present invention is characterized by comprising the semiconductor device of one aspect of the present invention described above.

[0246] The electronic circuit of this solution uses semiconductor devices that incorporate the above-mentioned solution, resulting in excellent electrical characteristics and high reliability.

[0247] 6. Electrical equipment, electronic equipment, vehicles, or power units An electrical device, electronic device, vehicle, or power unit according to one aspect of the present invention is characterized by including the electronic circuitry described above according to one aspect of the present invention.

[0248] The electrical equipment, electronic equipment, vehicles, or power units of this solution, through electronic circuits incorporating the above solution, exhibit excellent electrical characteristics and high reliability.

[0249] Example The present invention will now be described in more detail using examples and comparative examples, but the present invention is not limited thereto.

[0250] <Fabrication of Oxide Semiconductor Films 1> Using triethylin as an indium precursor, an oxide semiconductor film was fabricated on a glass substrate using an ALD apparatus (apparatus name: Fiji F200; manufactured by Veeco) under the conditions and procedures described in Examples 1, 2 and Comparative Example 1 below.

[0251] For the obtained oxide semiconductor film, the following measurements were performed: film thickness by X-ray reflectance (XRR); carbon and hydrogen concentrations in the film by SIMS; Hall mobility and carrier concentration by Hall measurement; crystal orientation by X-ray diffraction (XRD) or electron beam diffraction (ED); presence or absence of a peridotite structure by planar TEM or cross-sectional TEM; and surface roughness Ra of the film surface by atomic force microscopy (AFM). The results are shown in Table 1.

[0252] Example 1 The oxide semiconductor film was manufactured under the following conditions and procedures.

[0253] (condition) Substrate temperature during film formation: 100℃ Reactive gas (oxidant): H2O (Process) A series of steps consisting of (1) to (4) was taken as one cycle and repeated for 214 cycles.

[0254] (1) Open the valve for 0.06 seconds and introduce the vapor of triethylin obtained by heating the raw material container at a temperature of 95°C into the chamber. Expose it to the substrate surface or membrane surface for 15 seconds under a system pressure of 100Pa to allow it to react and adsorb.

[0255] (2) Remove unreacted raw materials by purging with argon gas for 15 seconds.

[0256] (3) At room temperature (25°C), a steel cylinder containing H2O is bubbled with argon gas. The valve is opened to introduce the water vapor into the chamber at a flow rate of 30 sccm, and the mixture is allowed to stabilize for 10 seconds. Then, plasma is generated for 20 seconds using an RF power supply with an output power of 300W. The RF power supply is then turned off, and the valve is closed.

[0257] (4) Remove unreacted raw materials by purging with argon gas for 45 seconds.

[0258] Example 2 Except that the substrate temperature during film formation was set to 150°C and the number of cycles was set to 429, an oxide semiconductor film was manufactured in the same manner as in Example 1.

[0259] Comparative Example 1 Except that the substrate temperature during film formation was set to 250°C and the number of cycles was set to 309, an oxide semiconductor film was manufactured in the same manner as in Example 1.

[0260] Reference Example 1 The oxide semiconductor film was manufactured under the following conditions and procedures.

[0261] (condition) Substrate temperature during film formation: 150℃ Reactive gas (oxidant): O2 (Process) A series of steps consisting of (1) to (4) was considered as one cycle, and the cycle was repeated 263 times.

[0262] (1) Open the valve for 0.06 seconds and introduce the vapor of triethylin obtained by heating the raw material container at a temperature of 95°C into the chamber. Expose it to the substrate surface or membrane surface for 15 seconds under a system pressure of 100Pa to allow it to react and adsorb.

[0263] (2) Remove unreacted raw materials by purging with argon gas for 15 seconds.

[0264] (3) Open the valve of the oxygen cylinder and introduce oxygen into the chamber at a flow rate of 50 sccm, and wait 10 seconds for it to stabilize. Then, generate plasma for 20 seconds using an RF power supply with an output power of 300W. Turn off the RF power supply and close the valve.

[0265] (4) Remove unreacted raw materials by purging with argon gas for 45 seconds.

[0266] Comparative Example 2 Except that the substrate temperature during film formation was set to 100°C and the number of cycles was set to 333, an oxide semiconductor film was manufactured in the same manner as the reference example.

[0267] Table 1

[0268] The “film formation temperature” in the table refers to the substrate temperature during the film formation process described above. “E+XX” indicates “×10”. XX ".

[0269] <Characteristic Evaluation of Oxide Semiconductor Films> (Measurement of carbon and hydrogen concentrations via SIMS) (A) Measurement of average carbon concentration and average hydrogen concentration in oxide semiconductor films The oxide semiconductor films obtained in the examples and comparative examples were annealed at 450°C for 1 hour under atmospheric conditions. SIMS depth direction analysis was performed using a time-of-flight secondary ion mass spectrometer (ToF-SIMS). The elemental composition in the depth direction was analyzed by detecting the intensity of secondary ions, and the carbon and hydrogen concentrations in the oxide semiconductor films were measured. C (mass number 12) and H (mass number 1) were detected as secondary ions. For the secondary ions C and H, the concentration was converted using In₂O₃ as a standard sample. The measurement conditions are shown below.

[0270] (Measurement conditions) Measuring device: PHI ADEPT1010; manufactured by ULVAC-Phi Inc. Primary ionic species: Cs+ Primary acceleration voltage: 2.0kV Detection area: 126×126 (μm×μm) (B) Depth Profile SIMS depth-direction analysis was performed on oxide semiconductor films using the time-of-flight secondary ion mass spectrometer described in item (A) above.

[0271] In this measurement, the InO intensity remained constant 2 nm from the surface. Furthermore, the interface between the oxide semiconductor film and the substrate was defined as the point at which the InO intensity reached half the maximum InO intensity.

[0272] The concentrations of carbon and hydrogen were set as the average values ​​from a depth of 2 nm from the surface of the oxide semiconductor film to a depth of half the maximum intensity of InO. (The measurement interval was 0.14 nm.) It should be noted that, for samples smaller than 2nm, performing FIB processing from the back side allows for measurement without affecting the surface and upper interface.

[0273] It should be noted that, under the same film formation conditions (substrate temperature and oxidation conditions during film formation), SIMS measurements were performed on the sample of the embodiment with the largest film thickness, and the carbon and hydrogen concentrations were calculated as described above. For the embodiment with the same film formation conditions and a smaller film thickness, the average carbon and hydrogen concentrations from the substrate interface defined above to the portion corresponding to the film thickness were calculated using the SIMS data of the sample with the largest film thickness.

[0274] (Measurement of carrier concentration via Hall effect measurement) The carrier concentration of the oxide semiconductor film was measured by the following method.

[0275] A glass substrate with an oxide film was cut into 1 cm square pieces and annealed at 450°C for 1 hour under atmospheric conditions. Electrodes were formed at the four corners using In solder as elements for Hall effect measurement, and the carrier concentration was measured. The carrier concentration was determined by AC Hall effect measurement at room temperature using a ResiTest 8400 (manufactured by Toyo Tecnica Corporation). The measurement conditions are shown below.

[0276] For measurement accuracy, the electron carrier concentration values ​​were used when the F value was 0.9 or higher and the absolute phase value of the Hall voltage was 170° to 180°.

[0277] Current value: 1×10 -12 ~1×10 -3 A Magnetic field strength: 0.36T (Measurement of Hall mobility via Hall measurement) Hall mobility is measured using the following method.

[0278] A glass substrate with an oxide film was cut into 1 cm squares and annealed at 450°C for 1 hour. In solder was then attached to the four corners to form electrodes, which served as the element for Hall effect measurement. Annealing was performed in a nitrogen atmosphere at 200°C for 5 minutes, 250°C for 5 minutes, and 300°C for 5 minutes to generate oxygen vacancies, increasing the carrier concentration to near that required for transistor operation. The Hall mobility was determined by AC Hall effect measurement at room temperature using a ResiTest8400 (manufactured by Toyo Tecnica). Although several samples exhibited different annealing conditions, the Hall mobility of the sample showing the highest mobility was used. The measurement conditions are shown below.

[0279] For measurement accuracy, the Hall mobility value was used when the F value was 0.9 or higher and the absolute value of the Hall voltage phase was 170° to 180°.

[0280] Current value: 1×10-12 ~1×10 -3 A Magnetic field strength: 0.36T (Film thickness measurement via XRR) The thickness of the oxide semiconductor film was determined by X-ray reflectivity (XRR). Specifically, the film thickness was determined by simulating and fitting the measured cross-section. Furthermore, the fitting was performed based on the assumption that the oxide semiconductor film was a monolayer formed on a glass substrate. Moreover, the XRR measurement results were confirmed to be correct in a subset of samples using cross-sectional TEM measurements (described in the detailed description).

[0281] The measurement conditions are shown below.

[0282] Measurement device: SmartLab (Science-based system) X-ray source: CuKα line (1.5418 Å), output power 45 kV, 200 mA Incident optical system: parallel beam optical system Light-receiving side of the cable slit: 5.0° Slit: IS = 1.0 mm on the incident side On the light-receiving side, RS1 = 1.0 mm, RS2 = 1.0 mm. Scanning conditions: Scanning axis 2θ / θ Scanning speed 2° / minute Step size 0.02° (Measurement of crystal orientation by XRD) X-ray diffraction (XRD) measurements were performed on a substrate with an oxide thin film to observe the crystal orientation.

[0283] Specifically, using an X-ray diffraction apparatus (Rigaku "SmartLab type"), a parallel beam of CuKα line (1.5418 Å) was incident on the oxide thin film, and the diffraction pattern of 2θ in the range of 5–80° was measured by 2θ / θ measurement. The measurement conditions are shown below.

[0284] Measurement device: SmartLab (Science-based system) X-ray source: CuKα line (1.5418 Å), output power 45 kV, 200 mA Incident optical system: parallel beam optical system Light-receiving side of the cable slit: 5.0° Slit: IS = 1.0 mm on the incident side On the light-receiving side, RS1 = 1.0 mm, RS2 = 1.0 mm. Scanning conditions: Scanning axis 2θ / θ Scanning speed: 2° / minute Step size: 0.02° For the sample of the oxide semiconductor film that yielded the peak, the peak was attributed to the (222) and (400) peaks of the indium oxide ferromanganese oxide structure.

[0285] The peak areas of (222) and (400) in the obtained spectrum were calculated. The aforementioned orientation rate OR （222） / （400） As shown in Table 1.

[0286] Orientation rate OR （222） / （400） If the value is 1 or higher, it is determined to be a crystal structure with {111} orientation predominance. Alternatively, TEM-EBSD can also be used for confirmation.

[0287] (Measurement of crystal orientation by electron beam diffraction of TEM) The electron beam diffraction pattern of the sample is obtained by observing the sample through cross-sectional TEM or planar TEM using a glass substrate with an oxide thin film.

[0288] Specifically, using an electron microscope (JEM-200 type manufactured by Nippon Electron), the electron beam was irradiated with an electron beam of approximately 100 nmφ and an accelerating voltage of 200 kV on the oxide thin film region observed through a planar TEM image using a selected area aperture, with the camera length set to 800 mm, and the diffraction pattern was measured.

[0289] To further identify the crystal structure, the electron beam diffraction pattern of the In₂O₃ ferromanganese structure was simulated using the electron beam diffraction simulation software ReciPro (free software ver4.641 (2019 / 03 / 04)). In the simulation, the crystal structure data for the ferromanganese structure was obtained from ICSD (Inorganic Crystal Structure Database) 14388, with space group Ia-3, lattice constant a = 10.17700 Å, and atomic coordinates: In site (0.250, 0.250, 0.250), In site (0.466, 0.000, 0.250), and O site (0.391, 0.156, 0.380). The camera length was set to 800 mm, and the reciprocal lattice vector (100) was used as the incident electron beam direction in the simulation.

[0290] Regarding the measurements, the beam shape of the selected-area electron diffraction (SAED) was adjusted to obtain individual spots. The electron beam diffraction pattern of the oxide thin film was compared with the obtained simulated pattern to obtain the diffraction spot results. More than 5 out of the 10 measured points were similar to... Figure 5 (The diagram showing the simulated spectrum with {100} orientation) indicates that the oxide thin film has a {100} orientation. It should be noted that the 10 measurement points were measured at equal intervals.

[0291] Figure 5 An example of electron beam diffraction spots obtained in an oxide semiconductor film fabricated by ALD is shown. From Figure 5 The electron beam diffraction spots show that they have a {100} orientation.

[0292] (The structure of ferromanganese was determined by electron beam diffraction using TEM) The method for determining the crystal state uses a glass substrate with an oxide thin film, and the electron beam diffraction pattern of the sample is obtained by observing it through cross-sectional TEM or planar TEM. For ultrathin films with insufficient intensity in cross-sectional TEM, electron beam diffraction patterns are obtained while simultaneously supplementing the intensity using planar TEM.

[0293] Specifically, using an electron microscope (JEM-F200, Nippon Electron), for oxide film regions observed at 1,000,000x magnification in a planar TEM image, a selected area aperture was used to illuminate an electron beam with an irradiation area of ​​approximately 100 nmφ and an accelerating voltage of 200 kV, and diffraction patterns were measured. Within a 10 μm range of the sample in the planar TEM image, 10 fields of view were extracted at approximately equal intervals with non-overlapping observation points. When the channel length was short and the extracted range was limited to less than 10 μm, 10 fields of view were also extracted at approximately equal intervals with non-overlapping observation points. For the extracted 10 fields of view, oxide films that did not produce clear diffraction spots in any field of view were judged as "amorphous." On the other hand, those with symmetrical diffraction points observed in the diffraction pattern in any field of view were judged as crystalline.

[0294] (Surface roughness measurement via AFM) The surface roughness Ra of a glass substrate with an oxide film was measured using AFM (atomic force microscopy) and the arithmetic mean roughness of a 5 μm × 5 μm square field of view was calculated.

[0295] Measuring device: E-SWEEP (Hitachi High Technology Manufacturing) Probe: SI-DF40 Measurement mode: DFM Scan speed: 2s / line Resolution: 512×256 It should be noted that when the surface cannot be obtained due to protective films or other reasons, Ra can be calculated from cross-sectional TEM measurements.

[0296] As can be seen from the results in Table 1, the oxide semiconductor films of Examples 1 and 2, which are fabricated using ALD during film formation and have a manganese ferromagnetic structure with {100} orientation relative to the crystal plane of the underlying surface, exhibit low carrier concentration suppression, high Hall mobility, and sufficient electrical properties, making them suitable for use in semiconductor devices.

[0297] In contrast, Comparative Examples 1 and 2, which have a ferromanganese structure but do not have a {100} orientation relative to the crystal plane of the lower surface, have a 222 orientation that is dominant. They have high carrier concentrations or low Hall mobility, indicating that they do not have sufficient electrical properties.

[0298] <Manufacturing of Bottom-Gate Top-Contact Transistors 1> (Manufacturing of transistor A 1) Example A-1 A 60 nm thick thermal oxide film was formed using a conductive n-type silicon substrate. The thermal oxide film functions as a gate insulating film, and the conductive silicon portion functions as a gate electrode. First, the surface of the gate insulating film was treated with SPM solution and UV / O3 to obtain a clean surface. An oxide semiconductor film was formed on the gate insulating film using the ALD method under the conditions described in Example 1 above. It should be noted that hexamethyldisilazane (HMDS) was coated on the surface of the oxide semiconductor layer to improve the adhesion between the oxide semiconductor layer and the positive photoresist. To pattern the oxide semiconductor layer, a positive photoresist was used, followed by coating, pre-baking (90°C, 1 minute 30 seconds), and exposure. After exposure, heating was performed at 110°C for 1 minute 30 seconds. After development, post-baking (110°C, 1 minute 30 seconds) was performed, followed by etching with a 500 mM oxalic acid aqueous solution to pattern the desired shape. It should be noted that when etching with oxalic acid aqueous solution fails to progress or produces residue, dilute hydrochloric acid heated to 50°C is used as the etchant. Subsequently, to remove the photoresist and clean the oxide semiconductor film surface, a UV / O3 treatment at 115°C for 10 minutes is performed. The patterned oxide semiconductor film is then subjected to a heat treatment (annealing) at 450°C for 120 minutes in a hot air furnace.

[0299] After forming the release photoresist, tungsten (80 nm) and platinum (20 nm) films were sequentially deposited by RF sputtering, and patterned into the desired shapes for the source and drain electrodes using a lift-off method. The oxide semiconductor film surface was then cleaned again by UV / O3 treatment at 115°C for 10 minutes. Next, a release photoresist was formed to create openings for the contact holes, and aluminum oxide was deposited at 200 nm by RF sputtering, which was then removed and used as a protective film. Finally, the transistor was annealed at 350°C under a nitrogen atmosphere.

[0300] Example A-2 Except that an oxide semiconductor film was formed by ALD under the conditions described in Example 2 instead of Example 1, a transistor was obtained in the same manner as in Example A-1.

[0301] See Example A-1 Except that an oxide semiconductor film was formed by ALD under the conditions described in Reference Example 1 instead of Example 1, a transistor was obtained in the same manner as in Example A-1.

[0302] Comparative Example A-1 Except that an oxide semiconductor film was formed by ALD under the conditions described in Comparative Example 2 instead of Example 1, a transistor was obtained in the same manner as in Example A-1.

[0303] The results of evaluating the following characteristics of the transistors obtained in Examples A-1, A-2, Reference Example A-1 and Comparative Example A-1 are shown in Table 2.

[0304] Table 2

[0305] <Transistor Characteristic Evaluation> The transistors manufactured in Examples A-1, A-2, Reference Example A-1, and Comparative Example A-1 were evaluated for mobility, threshold voltage, S-value, and reliability. The results are shown in Table 2.

[0306] Specifically, the transistors obtained in the above embodiments, reference examples, and comparative examples were measured using a semiconductor device analyzer (Agilent Technologies "B1500") in a light-protected environment (within a shielded box) at room temperature. It should be noted that the drain voltage (Vd) was applied in increments of 0.1V or 0.1V / nm. For each Vd application, the current value Id of the gate voltage (Vg) from -10V to 20V or from -0.5V / nm to 0.5V / nm was measured in steps of 0.2V or 0.002V / nm, thus obtaining the Id-Vg characteristic. Here, the unit of applied voltage, V / nm, is defined as the value obtained by dividing the applied voltage by the EOT (equivalent oxide thickness) of the gate insulating film. It should be noted that EOT refers to the value after converting the high dielectric constant film thickness into an electrical film thickness equivalent to the SiO2 film, expressed as EOT = [target insulating film thickness] × [relative permittivity of SiO2 film] / [target insulating film relative permittivity]. That is, it is not the physical thickness of a high dielectric constant film, but the equivalent film thickness when converted to the thickness of a SiO2 film with the same capacitance value. For example, since the relative permittivity of hafnium oxide film is 20, the equivalent film thickness is 5.1 times that of SiO2 film (relative permittivity 3.9).

[0307] The various parameters calculated from the Id-Vg characteristics are shown in Table 2. It should be noted that the calculation methods for each parameter are as follows.

[0308] (a) Maximum linear mobility (μlin Max) The maximum linear mobility when Vd=0.1V is obtained by plotting the Id-Vg characteristics, calculating the transconductance (Gm) of each Vg, and deriving the linear mobility (μlin) using the formula for the linear region.

[0309] Specifically, Gm through (Id) / (Vg) is calculated.

[0310] μlin was then calculated using the following equation (c) for the linear region.

[0311] μlin=(Gm·L) / (W·Ci·Vd)…(c) In equation (c), Ci is the capacitance of the gate insulating film, using a value based on the gate insulating film thickness, the relative permittivity of SiO2 (3.9), and the vacuum permittivity (8.85 × 10⁻⁶). -14 Ci[F / cm] calculated from [F / cm] 2 The value of ].

[0312] In equation (c), L is the channel length (L_length) and W is the channel width (W_length).

[0313] Furthermore, from the charts of Vg-μlin, the maximum value of μlin at Vg = -20V to 20V or -0.5V / nm to 0.5V / nm was calculated and defined as "μlin Max". Additionally, in Tables 2 and 3, the mobility at the gate voltage of Vg-Vth = 18V is defined as μlin at Vg-Vth = 18V [cm]. 2 / Vs]. It should be noted that the threshold voltage Vth is defined as follows.

[0314] (b) S value and threshold voltage Vth The S-value and threshold voltage (Vth) were evaluated from the graphs of each Id-Vg characteristic.

[0315] Specifically, when the current value Id = 100pA to 10nA or 5 × 10 -7 ~5×10 -6 In the [mA / mm] region, the value obtained by the following formula (d) is used as the S value. Furthermore, the current value Id = 1nA or 5 × 10⁻⁶ is calculated. -6 The value of Vg at [mA / mm] is used as the threshold voltage (Vth). Here, the unit of the current value Id is the normalized value obtained by dividing the measured current value by the channel width W.

[0316]

Number 2

[0317] (C) Reliability The reliability of the transistors was evaluated through stress testing. Positive bias stress testing (PBS) and negative bias stress testing (NBS) were performed.

[0318] The PBS is applied at 25°C with Vg = +20V. The threshold voltage (Vth) after 10,000 seconds is compared with that before the test, and the difference is taken as ΔVth.

[0319] The NBS applies Vg=-20V at 25℃, and compares the threshold voltage (Vth) after 10,000 seconds with the voltage before the test, and takes the difference as ΔVth.

[0320] It should be noted that the threshold voltage (Vth) is set to the gate voltage value when the current value Id = 1nA.

[0321] Regarding the above, Table 2 and Table 3 respectively record it as "PBS shift ΔVth[V] Vg at Id=1nA" (PBS threshold voltage drift) and "NBS shift ΔVth[V] Vg at Id=1nA" (NBS threshold voltage drift).

[0322] The results in Tables 2 and 3 show that transistors containing an oxide semiconductor film with a manganese oxide structure and a {100} orientation relative to the crystal plane of the lower layer as the channel layer exhibit excellent performance in terms of mobility, threshold voltage, and S-value.

[0323] <Fabrication of Oxide Semiconductor Films 2> Using triethylindium (TEI) as an indium precursor and trimethylgallium (TMG) as a gallium precursor, an oxide semiconductor film was fabricated on a glass substrate using an ALD apparatus (apparatus name: Fiji F200; manufactured by Veeco) under the conditions and procedures described in Examples 3 to 6 below.

[0324] For the obtained oxide semiconductor film, the following measurements were performed: film thickness by X-ray reflectance (XRR); carbon and hydrogen concentrations in the film by SIMS; Hall mobility and carrier concentration by Hall measurement; crystal orientation by X-ray diffraction (XRD) or electron beam diffraction (ED); presence or absence of a peridotite structure by planar TEM or cross-sectional TEM; and surface roughness Ra of the film surface by atomic force microscopy (AFM). The results are shown in Table 4.

[0325] Example 3 The oxide semiconductor film was manufactured under the following conditions and procedures.

[0326] (condition) Substrate temperature during film formation: 150℃ Reactive gas (oxidant): O2 (Process) Using triethylindium (TEI) as a precursor, steps (1) to (4) described in the following (indium film formation process) were repeated 22 times to obtain film 1. On film 1, using trimethylgallium (TMG) as a precursor, steps (1) to (4) described in the following (gallium film formation process) were performed once to obtain film 2. On film 2, using triethylindium (TEI) as a precursor, steps (1) to (4) described in the following (indium film formation process) were repeated 22 times to obtain film 3. Furthermore, each step of forming films 1 to 3 was treated as a sub-cycle, and a super-cycle was performed a total of 6 times to form a series of film formation operations from films 1 to 3 as one cycle, thereby obtaining an oxide semiconductor film. It should be noted that the manufacturing conditions shown in Table 3 were used.

[0327] (Indium film formation process) A series of steps consisting of (1) to (4) is taken as one cycle and repeated until the specified number of cycles is reached.

[0328] (1) Open the valve for 0.06 seconds to introduce the vapor of the precursor obtained by heating the raw material container at a temperature of 85°C into the chamber and expose it to the substrate surface or membrane surface under a system pressure of 100Pa, so that it reacts and adsorbs.

[0329] (2) Remove unreacted raw materials by purging with argon gas for 15 seconds.

[0330] (3) Open the valve to introduce oxygen (O2) gas into the chamber at a flow rate of 50 sccm, and wait 10 seconds for it to stabilize. Then, generate plasma for 20 seconds using an RF power supply with an output power of 300W. Turn off the RF power supply and close the valve.

[0331] (4) Remove unreacted raw materials by purging with argon gas for 30 seconds.

[0332] (Gallium film deposition process) A series of steps consisting of (1) to (4) is taken as one cycle and repeated until the specified number of cycles is reached.

[0333] (1) Set the raw material container to room temperature 25°C, open the valve for 0.02 seconds to introduce the vapor of the vaporized precursor into the chamber, and expose it to the substrate surface or membrane surface under a system pressure of 100Pa to allow it to react and adsorb.

[0334] (2) Remove unreacted raw materials by purging with argon gas for 15 seconds.

[0335] (3) Open the valve to introduce oxygen (O2) gas into the chamber at a flow rate of 50 sccm, and wait 10 seconds for it to stabilize. Then, generate plasma for 20 seconds using an RF power supply with an output power of 300W. Turn off the RF power supply and close the valve.

[0336] (4) Remove unreacted raw materials by purging with argon gas for 30 seconds.

[0337] For Examples 4 and 5, the same number of film depositions, supercycles, and precursors shown in Table 3 were used to fabricate oxide semiconductor films (oxide semiconductor layers).

[0338] Example 6 The oxide semiconductor film was manufactured under the following conditions and procedures.

[0339] (condition) Substrate temperature during film formation: 150℃ Reactive gas (oxidant): H2O (Process) In the oxide semiconductor film formation method of Example 6, triethylindium (TEI) was used as a precursor, and steps (1) to (4) described below (indium film formation steps) were repeated 19 times to obtain film 1. On film 1, trimethylgallium (TMG) was used as a precursor, and steps (1) to (4) described below (gallium film formation steps) were performed once to obtain film 2. On film 2, triethylindium (TEI) was used as a precursor, and steps (1) to (4) described below (indium film formation steps) were repeated 19 times to obtain film 3. Furthermore, each step of forming films 1 to 3 was treated as a sub-cycle, and a super-cycle was performed a total of 6 times to form a series of film formation operations from films 1 to 3 as one cycle, thereby obtaining an oxide semiconductor film. It should be noted that the manufacturing conditions shown in Table 3 were used.

[0340] (Indium film formation process) A series of steps consisting of (1) to (4) is taken as one cycle and repeated until the specified number of cycles is reached.

[0341] (1) Open the valve for 0.06 seconds to introduce the vapor of the precursor obtained by heating the raw material container at a temperature of 85°C into the chamber and expose it to the substrate surface or membrane surface under a system pressure of 100Pa, so that it reacts and adsorbs.

[0342] (2) Remove unreacted raw materials by purging with argon gas for 15 seconds.

[0343] (3) At room temperature (25°C), a steel cylinder containing H2O is bubbled with argon gas. The valve is opened to introduce the water vapor into the chamber at a flow rate of 10 sccm, and the mixture is allowed to stabilize for 10 seconds. Then, plasma is generated for 20 seconds using an RF power supply with an output power of 300W. The RF power supply is then turned off, and the valve is closed.

[0344] (4) Remove unreacted raw materials by purging with argon gas for 30 seconds.

[0345] (Gallium film deposition process) A series of steps consisting of (1) to (4) is taken as one cycle and repeated until the specified number of cycles is reached.

[0346] (1) Set the raw material container to room temperature 25°C, open the valve for 0.02 seconds to introduce the vapor of the vaporized precursor into the chamber, and expose it to the substrate surface or membrane surface under a system pressure of 100Pa to allow it to react and adsorb.

[0347] (2) Remove unreacted raw materials by purging with argon gas for 15 seconds.

[0348] (3) At room temperature (25°C), a steel cylinder containing H2O is bubbled with argon gas. The valve is opened to introduce the water vapor into the chamber at a flow rate of 10 sccm, and the mixture is allowed to stabilize for 10 seconds. Then, plasma is generated for 20 seconds using an RF power supply with an output power of 300W. The RF power supply is then turned off, and the valve is closed.

[0349] (4) Remove unreacted raw materials by purging with argon gas for 30 seconds.

[0350] Table 3

[0351] Table 4

[0352] As can be seen from the results in Table 4, the oxide semiconductor films of Examples 3 to 6, which were fabricated using ALD during film formation and have a ferromanganese oxide structure with {100} orientation relative to the crystal plane of the underlying layer, have low carrier concentration, high Hall mobility, and sufficient electrical properties, making them suitable for use in semiconductor devices.

[0353] <Manufacturing of Oxide Semiconductor Films 3> Using ethylcyclopentadienyl indium (I) (InEtCp) as an indium precursor, an oxide semiconductor film was fabricated on a glass substrate using an ALD apparatus (Apparatus name: Fiji F200; manufactured by Veeco) under the conditions and procedures described in Example 7 below.

[0354] For the obtained oxide semiconductor film, the following measurements were performed: film thickness by X-ray reflectance (XRR); carbon and hydrogen concentrations in the film by SIMS; Hall mobility and carrier concentration by Hall measurement; crystal orientation by X-ray diffraction (XRD) or electron beam diffraction (ED); presence or absence of a peridotite structure by planar TEM or cross-sectional TEM; and surface roughness Ra of the film surface by atomic force microscopy (AFM). The results are shown in Table 5.

[0355] Example 7 The oxide semiconductor film was manufactured under the following conditions and procedures.

[0356] (condition) Substrate temperature during film formation: 150℃ Reactive gas (oxidant): H2O (Process) A series of steps consisting of (1) to (4) was taken as one cycle and repeated 114 times.

[0357] (1) Open the valve for 0.04 seconds to introduce the vapor of ethylcyclopentadienyl indium (I) obtained by heating the raw material container at a temperature of 85°C into the chamber. Under a system pressure of 100Pa, it is exposed to the substrate surface or membrane surface for 15 seconds to react and adsorb.

[0358] (2) Remove unreacted raw materials by purging with argon gas for 15 seconds.

[0359] (3) At room temperature (25°C), a steel cylinder containing H2O is bubbled with argon gas. The valve is opened to introduce the water vapor into the chamber at a flow rate of 30 sccm, and the mixture is allowed to stabilize for 10 seconds. Then, plasma is generated for 60 seconds using an RF power supply with an output power of 300W. The RF power supply is then turned off, and the valve is closed.

[0360] (4) Remove unreacted raw materials by purging with argon gas for 45 seconds.

[0361] Table 5

[0362] As can be seen from the results in Table 5, the oxide semiconductor film of Example 7, which was fabricated using ALD during film formation and has a manganese ferromagnetic structure with {100} orientation relative to the crystal plane of the underlying surface, has a low carrier concentration, high Hall mobility, and sufficient electrical properties, making it suitable for use in semiconductor devices.

[0363] <Manufacturing of Oxide Semiconductor Films 4> Using triethylindium (TEI) as an indium precursor and triethylgallium (TEG) as a gallium precursor, an oxide semiconductor film was fabricated on a glass substrate using an ALD apparatus (apparatus name: Fiji F200; manufactured by Veeco) under the conditions and procedures described in Examples 8 to 11 below.

[0364] For the obtained oxide semiconductor film, the following measurements were performed: film thickness by X-ray reflectance (XRR); carbon and hydrogen concentrations in the film by SIMS; Hall mobility and carrier concentration by Hall measurement; crystal orientation by X-ray diffraction (XRD) or electron beam diffraction (ED); presence or absence of a peridotite structure by planar TEM or cross-sectional TEM; and surface roughness Ra of the film surface by atomic force microscopy (AFM). The results are shown in Table 7.

[0365] Example 8 The oxide semiconductor film was manufactured under the following conditions and procedures.

[0366] (condition) Substrate temperature during film formation: 150℃ Reactive gas (oxidant): O2 (Process) Using triethylindium (TEI) as a precursor, steps (1) to (4) described in the following (indium film formation process) were repeated 22 times to obtain film 1. On film 1, using triethylgallium (TEG) as a precursor, steps (1) to (4) described in the following (gallium film formation process) were performed once to obtain film 2. On film 2, using triethylindium (TEI) as a precursor, steps (1) to (4) described in the following (indium film formation process) were repeated 22 times to obtain film 3. Furthermore, each step of forming films 1 to 3 was treated as a sub-cycle, and a super-cycle was performed a total of 6 times to form a series of film formation operations from films 1 to 3 as one cycle, thereby obtaining an oxide semiconductor film. It should be noted that the manufacturing conditions shown in Table 6 were used.

[0367] (Indium film formation process) A series of steps consisting of (1) to (4) is taken as one cycle and repeated until the specified number of cycles is reached.

[0368] (1) Open the valve for 0.06 seconds to introduce the vapor of the precursor obtained by heating the raw material container at a temperature of 85°C into the chamber and expose it to the substrate surface or membrane surface under a system pressure of 100Pa, so that it reacts and adsorbs.

[0369] (2) Remove unreacted raw materials by purging with argon gas for 15 seconds.

[0370] (3) Open the valve to introduce oxygen (O2) gas into the chamber at a flow rate of 50 sccm, and wait 10 seconds for it to stabilize. Then, generate plasma for 20 seconds using an RF power supply with an output power of 300W. Turn off the RF power supply and close the valve.

[0371] (4) Remove unreacted raw materials by purging with argon gas for 30 seconds.

[0372] (Gallium film deposition process) A series of steps consisting of (1) to (4) is taken as one cycle and repeated until the specified number of cycles is reached.

[0373] (1) Set the raw material container to room temperature 25°C, open the valve for 0.06 seconds to introduce the vapor of the vaporized precursor into the chamber, and expose it to the substrate surface or membrane surface under a system pressure of 100Pa to allow it to react and adsorb.

[0374] (2) Remove unreacted raw materials by purging with argon gas for 15 seconds.

[0375] (3) Open the valve to introduce oxygen (O2) gas into the chamber at a flow rate of 50 sccm, and wait 10 seconds for it to stabilize. Then, generate plasma for 20 seconds using an RF power supply with an output power of 300W. Turn off the RF power supply and close the valve.

[0376] (4) Remove unreacted raw materials by purging with argon gas for 30 seconds.

[0377] For Examples 9-11, the same number of film depositions, supercycles, and precursors shown in Table 6 were used to fabricate oxide semiconductor films (oxide semiconductor layers).

[0378] Table 6

[0379] Table 7

[0380] As can be seen from the results in Table 7, the oxide semiconductor films of Examples 8-11, which were fabricated using ALD during film formation and have a ferromanganese oxide structure with {100} orientation relative to the crystal plane of the underlying layer, exhibited low carrier concentration, high Hall mobility, and sufficient electrical properties, making them suitable for use in semiconductor devices.

[0381] <Manufacturing of Oxide Semiconductor Films 5> Using triethylindium (TEI) as an indium precursor, an oxide semiconductor film was fabricated on a glass substrate using an ALD apparatus (apparatus name: Fiji F200; manufactured by Veeco) under the conditions and procedures described in Example 12 below.

[0382] For the obtained oxide semiconductor film, the following measurements were performed: film thickness by X-ray reflectance (XRR); carbon and hydrogen concentrations in the film by SIMS; Hall mobility and carrier concentration by Hall measurement; crystal orientation by X-ray diffraction (XRD) or electron beam diffraction (ED); presence or absence of a peridotite structure by planar TEM or cross-sectional TEM; and surface roughness Ra of the film surface by atomic force microscopy (AFM). The results are shown in Table 8.

[0383] Example 12 The oxide semiconductor film was manufactured under the following conditions and procedures.

[0384] (condition) Substrate temperature during film formation: 150℃ Reactive gas (oxidant): H2O (Process) A series of steps consisting of (1) to (4) was considered as one cycle, and the cycle was repeated 338 times.

[0385] (1) Open the valve for 0.06 seconds to introduce the vapor of triethyl indium obtained by heating the raw material container at a temperature of 95°C into the chamber. Under a system pressure of 100Pa, it is exposed to the substrate surface or membrane surface for 15 seconds to react and adsorb.

[0386] (2) Remove unreacted raw materials by purging with argon gas for 15 seconds.

[0387] (3) At room temperature (25°C), a steel cylinder containing H2O is bubbled with argon gas. The valve is opened to introduce the water vapor into the chamber at a flow rate of 10 sccm, and the mixture is allowed to stabilize for 10 seconds. Then, plasma is generated for 20 seconds using an RF power supply with an output power of 300W. The RF power supply is then turned off, and the valve is closed.

[0388] (4) Remove unreacted raw materials by purging with argon gas for 45 seconds.

[0389] Table 8

[0390] As can be seen from the results in Table 8, the oxide semiconductor film of Example 12, which was fabricated using ALD during film formation and has a ferromanganese oxide structure with a {100} orientation relative to the crystal plane of the underlying layer, has a low carrier concentration, high Hall mobility, and sufficient electrical properties, making it suitable for use in semiconductor devices.

[0391] Industrial applicability The oxide semiconductor film of the present invention is suitable as a channel layer for transistors and can be used in various semiconductor devices. In particular, it is suitable for use in transistors for displays, FETs for memory (DRAM, NAND, ReRAM, FeRAM), FETs for logic ICs (CPU, MPU, BEOL, 3D-LSI, CMOS), FETs for sensors (CMOS image sensors), and transistors (MOSFET, power transistor, MESFET), etc.

[0392] The embodiments and / or examples of the present invention have been described in detail above. However, those skilled in the art can readily make many modifications to these exemplary embodiments and / or examples without substantially departing from the innovative teachings and effects of the present invention. Therefore, all such modifications are included within the scope of the present invention.

[0393] All documents described in this specification, as well as the contents of applications that form the basis of this application’s priority under the Paris Convention, are incorporated herein by reference.

Claims

1. An oxide semiconductor film having a manganese oxide structure and having a {100} orientation relative to the crystal plane of the underlying surface.

2. The oxide semiconductor film according to claim 1, in measurements performed according to Secondary Ion Mass Spectrometry (SIMS), has a carbon concentration of 1 × 10⁻⁶. 18 atoms / cm 3 Above and 5×10 19 atoms / cm 3 The following areas.

3. The oxide semiconductor film according to claim 1 or 2, wherein the film thickness is less than 20 nm.

4. The oxide semiconductor film according to any one of claims 1 to 3, wherein indium oxide is contained as the main component.

5. The oxide semiconductor film according to claim 4, wherein the atomic ratio of In in the oxide semiconductor film relative to all metal elements ([In] / ([In]+[all metal elements other than In])×100) is 62at% or more.

6. The oxide semiconductor film according to claim 4 or 5, further comprising Ga.

7. The oxide semiconductor film according to claim 6, wherein the atomic ratio of Ga to all metal elements contained in the oxide semiconductor film ([Ga] / ([Ga]+[all metal elements other than Ga])×100) is 30 at% or less.

8. The oxide semiconductor film according to any one of claims 4 to 7, further comprising one or more additive elements selected from B, Al, Si, Sc, Zn, Ce, Y, Zr, Sn, Sm, Hf, Ta and Yb.

9. The oxide semiconductor film according to claim 8, wherein the total amount of the added elements contained in the oxide semiconductor film is less than 10 at% relative to the atomic ratio of all metal elements ([total amount of added elements] / ([total amount of added elements]+[all metal elements other than added elements])×100).

10. The oxide semiconductor film according to any one of claims 4 to 9, wherein at least one of the X-ray diffraction pattern in X-ray diffraction and the electron beam diffraction spot in electron beam diffraction shows a ferromanganese structure.

11. The oxide semiconductor film according to any one of claims 1 to 10, wherein the carrier concentration at room temperature is 1 × 10⁻⁶. 19 cm -3 the following.

12. The oxide semiconductor film according to any one of claims 1 to 11, wherein the Hall mobility is 30 cm⁻¹. 2 / Vs and above.

13. The oxide semiconductor film according to any one of claims 1 to 12, wherein the surface roughness is 0.6 nm or less.

14. The oxide semiconductor film according to any one of claims 1 to 13, having a hydrogen concentration of 1 × 10⁻⁶ in measurements performed according to Secondary Ion Mass Spectrometry (SIMS). 18 atoms / cm 3 Above and 5×10 22 atoms / cm 3 The following areas.

15. The oxide semiconductor film according to any one of claims 1 to 14 is formed by atomic layer deposition, i.e., ALD.

16. An oxide semiconductor film having a manganese perforate structure and having a {100} orientation relative to a crystal plane of an underlying layer surface. The atomic ratio of In in the oxide semiconductor film relative to all metal elements ([In] / ([In]+[all metal elements other than In])×100) is 80 at% or more.

17. The oxide semiconductor film according to claim 16, wherein the orientation ratio OR of the (222) plane relative to the (400) plane is... （222） / （400） It is above 0.01 and below 0.

80.

18. The oxide semiconductor film according to claim 17, further comprising Ga.

19. A transistor having on a substrate a layer made of an oxide semiconductor film as described in any one of claims 1 to 18, an insulating film layer, and an electrode.

20. The transistor of claim 19, wherein it is a bottom-gate top-contact type.

21. The transistor of claim 19, wherein it is a top-gate top-contact type.

22. The transistor according to any one of claims 19 to 21, wherein the insulating film layer is mainly composed of hafnium oxide.

23. The transistor according to any one of claims 19 to 21, wherein the insulating film layer is mainly composed of silicon oxide.

24. The transistor according to any one of claims 19 to 21, wherein the insulating film layer is mainly composed of aluminum oxide.

25. The transistor according to any one of claims 19 to 24, wherein the electrode is composed primarily of titanium nitride.

26. The transistor according to any one of claims 19 to 24, wherein the electrode is mainly composed of tungsten.

27. A semiconductor device comprising the transistor according to any one of claims 19 to 26.

28. An electronic circuit comprising the semiconductor device of claim 27.

29. An electrical device, electronic device, vehicle or power unit comprising the electronic circuitry of claim 28.

30. A method for manufacturing an oxide semiconductor film according to any one of claims 1 to 18, comprising a step of forming a film using an indium-containing precursor via atomic layer deposition, i.e., ALD.

31. The method of claim 30, wherein triethylindium is used as the indium-containing precursor.

32. The method of claim 31, further comprising using a gallium-containing precursor.

33. The method according to any one of claims 30 to 32, wherein H2O plasma is used as an oxidant in the film-forming process.

34. The method according to any one of claims 30 to 32, wherein O2 plasma is used as an oxidant in the film-forming process.

35. The method according to any one of claims 30 to 34, wherein the oxide semiconductor film is an indium oxide film.

36. The method according to any one of claims 30 to 35, wherein the container holding the indium-containing precursor is heated in the range of 75 to 125°C.

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