US-12618141-B2 - Sintered body, sputtering target, oxide thin film, thin film transistor, electronic equipment, and method for producing sintered body

US12618141B2US 12618141 B2US12618141 B2US 12618141B2US-12618141-B2

Abstract

A sintered body of an oxide contains an In element, a Ga element, and an Al element, in which an atomic composition ratio of the In element and an atomic composition ratio of the Al element respectively satisfy a formula (1) and a formula (2) below, [ In ] / ( [ In ] + [ Ga ] + [ Al ] ) > 0 .70 ( 1 ) [ Al ] / ( [ In ] + [ Ga ] + [ Al ] ) > 0.01 . ( 2 )

Inventors

Emi Kawashima
Mami ITOSE
Akira Kaijo
Kazuyoshi Inoue
Nobuhiro Iwase

Assignees

IDEMITSU KOSAN CO.,LTD.

Dates

Publication Date: 20260505
Application Date: 20230307
Priority Date: 20220316

Claims (13)

1 . A sintered body of an oxide comprising an In element, a Ga element, and an Al element, wherein in a field of view when the sintered body is observed with a scanning electron microscope, an area ratio of pores to an area of the field of view is 0.1% or less, and wherein an atomic composition ratio of the In element and an atomic composition ratio of the Al element respectively satisfy a formula (1) and a formula (2) below, [ ln ] / ( [ ln ] + [ Ga ] + [ Al ] ) > 0.7 ( 1 ) [ Al ] / ( [ ln ] + [ Ga ] + [ Al ] ) > 0.01 . ( 2 )
2 . The sintered body according to claim 1 , wherein provided that an atomic composition ratio of the Ga element represented by {[Ga]/([In]+[Ga]+[Al])}×100 is x and an atomic composition ratio of the Al element represented by {[Al]/([In]+[Ga]+[Al])}×100 is y, the x and the y are, in atomic %, within a composition range bounded by straight lines of (A1), (B0), (C1), (D1), and (E1) below, x ≥ 4 ( A ⁢ 1 ) x ≤ 22.5 ( B ⁢ 0 ) y > 1 ( C ⁢ 1 ) 6 ⁢ x + 1 ⁢ 4 ⁢ y - 9 ⁢ 8 ≥ 0 ( D ⁢ 1 ) 4 ⁢ x + 2 ⁢ 0 ⁢ y - 1 ⁢ 8 ⁢ 0 ≤ 0. ( E ⁢ 1 )
3 . The sintered body according to claim 2 , wherein the x and the y are, in atomic %, within a composition range bounded by straight lines of (A2) and (B2) below and the straight lines of (C1), (D1), and (E1) above, x ≥ 8 ( A ⁢ 2 ) x ≤ 20. ( B ⁢ 2 )
4 . The sintered body according to claim 1 , comprising a Bixbyite structure comprising the In element and a crystal structure belonging to a space group Pl or a space group P-1, the crystal structure belonging to the space group P1 being represented by a crystal structure parameter (X) below, the crystal structure belonging to the space group P-1 being represented by a crystal structure parameter (Y) below, the crystal structure parameter (X): lattice constants are a=10.07±0.15 Å, b=10.45=0.15 Å, c=11.01±0.15 Å, α=111.70±0.50°, β=107.70±0.50°, and γ=90.00±0.50°, the sintered body has a triclinic crystal system, at least one metal in an atomic configuration below of the space group P1 is any one of In, Ga and Al, or any two or more of In, Ga and Al, and is on identical atomic coordinates at a predetermined ratio, the atomic coordinates on which the at least one metal is arranged are in a range of x±0.01, y±0.01, and z=0.01, and atomic coordinates on which oxygen is arranged are in a range of x±0.01, y=0.01, and z±0.01, where atomic species: metal, atomic coordinates (x=0.04, y=0.36, z=0.87), atomic species: metal, atomic coordinates (x=0.13, y=0.12, z=0.62), atomic species: metal, atomic coordinates (x=0.21, y=0.85, z=0.39), atomic species: metal, atomic coordinates (x=0.23, y=0.11, z=0.97), atomic species: metal, atomic coordinates (x=0.29, y=0.64, z=0.11), atomic species: metal, atomic coordinates (x=0.46, y=0.12, z=0.63), atomic species: metal, atomic coordinates (x=0.58, y=0.14, z=0.01), atomic species: metal, atomic coordinates (x=0.62, y=0.64, z=0.11), atomic species: metal, atomic coordinates (x=0.69, y=0.18, z=0.32), atomic species: metal, atomic coordinates (x=0.09, y=0.88, z=0.03), atomic species: metal, atomic coordinates (x=0.02, y=0.13, z=0.30), atomic species: metal, atomic coordinates (x=0.06, y=0.61, z=0.46), atomic species: metal, atomic coordinates (x=0.15, y=0.40, z=0.19), atomic species: metal, atomic coordinates (x=0.26, y=0.36, z=0.54), atomic species: metal, atomic coordinates (x=0.34, y=0.13, z=0.30), atomic species: metal, atomic coordinates (x=0.41, y=0.61, z=0.45), atomic species: metal, atomic coordinates (x=0.48, y=0.40, z=0.23), atomic species: metal, atomic coordinates (x=0.84, y=0.39, z=0.23), atomic species: metal, atomic coordinates (x=0.96, y=0.64, z=0.13), atomic species: metal, atomic coordinates (x=0.87, y=0.88, z=0.38), atomic species: metal, atomic coordinates (x=0.79, y=0.15, z=0.61), atomic species: metal, atomic coordinates (x=0.77, y=0.89, z=0.03), atomic species: metal, atomic coordinates (x=0.71, y=0.36, z=0.89), atomic species: metal, atomic coordinates (x=0.54, y=0.88, z=0.37), atomic species: metal, atomic coordinates (x=0.42, y=0.86, z=0.99), atomic species: metal, atomic coordinates (x=0.38, y=0.36, z=0.89), atomic species: metal, atomic coordinates (x=0.31, y=0.82, z=0.68), atomic species: metal, atomic coordinates (x=0.91, y=0.12, z=0.97), atomic species: metal, atomic coordinates (x=0.98, y=0.87, z=0.70), atomic species: metal, atomic coordinates (x=0.94, y=0.39, z=0.54), atomic species: metal, atomic coordinates (x=0.85, y=0.60, z=0.81), atomic species: metal, atomic coordinates (x=0.74, y=0.64, z=0.46), atomic species: metal, atomic coordinates (x=0.66, y=0.87, z=0.70), atomic species: metal, atomic coordinates (x=0.59, y=0.39, z=0.55), atomic species: metal, atomic coordinates (x=0.52, y=0.60, z=0.77), atomic species: metal, atomic coordinates (x=0.16, y=0.61, z=0.77), atomic species: oxygen, atomic coordinates (x=0.02, y=0.73, z=0.36), atomic species: oxygen, atomic coordinates (x=0.03, y=0.45, z=0.29), atomic species: oxygen, atomic coordinates (x=0.05, y=0.02, z=0.40), atomic species: oxygen, atomic coordinates (x=0.10, y=0.74, z=0.65), atomic species: oxygen, atomic coordinates (x=0.10, y=0.23, z=0.06), atomic species: oxygen, atomic coordinates (x=0.12, y=0.51, z=0.09), atomic species: oxygen, atomic coordinates (x=0.12, y=0.47, z=0.57), atomic species: oxygen, atomic coordinates (x=0.13, y=0.79, z=0.17), atomic species: oxygen, atomic coordinates (x=0.19, y=0.21, z=0.84), atomic species: oxygen, atomic coordinates (x=0.20, y=0.23, z=0.36), atomic species: oxygen, atomic coordinates (x=0.25, y=0.66, z=0.49), atomic species: oxygen, atomic coordinates (x=0.27, y=0.02, z=0.12), atomic species: oxygen, atomic coordinates (x=0.30, y=0.26, z=0.65), atomic species: oxygen, atomic coordinates (x=0.33, y=0.44, z=0.29), atomic species: oxygen, atomic coordinates (x=0.38, y=0.02, z=0.40), atomic species: oxygen, atomic coordinates (x=0.39, y=0.73, z=0.35), atomic species: oxygen, atomic coordinates (x=0.41, y=0.24, z=0.07), atomic species: oxygen, atomic coordinates (x=0.43, y=0.47, z=0.57), atomic species: oxygen, atomic coordinates (x=0.46, y=0.51, z=0.11), atomic species: oxygen, atomic coordinates (x=0.47, y=0.79, z=0.15), atomic species: oxygen, atomic coordinates (x=0.50, y=0.25, z=0.36), atomic species: oxygen, atomic coordinates (x=0.64, y=0.03, z=0.12), atomic species: oxygen, atomic coordinates (x=0.66, y=0.34, z=0.23), atomic species: oxygen, atomic coordinates (x=0.72, y=0.03, z=0.40), atomic species: oxygen, atomic coordinates (x=0.78, y=0.51, z=0.12), atomic species: oxygen, atomic coordinates (x=0.80, y=0.25, z=0.06), atomic species: oxygen, atomic coordinates (x=0.96, y=0.02, z=0.12), atomic species: oxygen, atomic coordinates (x=0.98, y=0.27, z=0.64), atomic species: oxygen, atomic coordinates (x=0.97, y=0.55, z=0.72), atomic species: oxygen, atomic coordinates (x=0.95, y=0.98, z=0.60), atomic species: oxygen, atomic coordinates (x=0.90, y=0.26, z=0.35), atomic species: oxygen, atomic coordinates (x=0.90, y=0.77, z=0.94), atomic species: oxygen, atomic coordinates (x=0.88, y=0.49, z=0.91), atomic species: oxygen, atomic coordinates (x=0.88, y=0.53, z=0.43), atomic species: oxygen, atomic coordinates (x=0.87, y=0.21, z=0.83), atomic species: oxygen, atomic coordinates (x=0.81, y=0.79, z=0.16), atomic species: oxygen, atomic coordinates (x=0.80, y=0.77, z=0.64), atomic species: oxygen, atomic coordinates (x=0.75, y=0.34, z=0.51), atomic species: oxygen, atomic coordinates (x=0.73, y=0.98, z=0.88), atomic species: oxygen, atomic coordinates (x=0.70, y=0.74, z=0.35), atomic species: oxygen, atomic coordinates (x=0.67, y=0.56, z=0.71), atomic species: oxygen, atomic coordinates (x=0.62, y=0.98, z=0.60), atomic species: oxygen, atomic coordinates (x=0.61, y=0.27, z=0.65), atomic species: oxygen, atomic coordinates (x=0.59, y=0.76, z=0.93), atomic species: oxygen, atomic coordinates (x=0.58, y=0.53, z=0.43), atomic species: oxygen, atomic coordinates (x=0.54, y=0.49, z=0.89), atomic species: oxygen, atomic coordinates (x=0.53, y=0.21, z=0.85), atomic species: oxygen, atomic coordinates (x=0.50, y=0.75, z=0.64), atomic species: oxygen, atomic coordinates (x=0.36, y=0.97, z=0.88), atomic species: oxygen, atomic coordinates (x=0.34, y=0.66, z=0.77), atomic species: oxygen, atomic coordinates (x=0.28, y=0.97, z=0.60), atomic species: oxygen, atomic coordinates (x=0.22, y=0.49, z=0.88), atomic species: oxygen, atomic coordinates (x=0.20, y=0.75, z=0.94), and atomic species: oxygen, atomic coordinates (x=0.04, y=0.98, z=0.88), the crystal structure parameter (Y): lattice constants are a=10.07±0.15 Å, b=10.45±0.15 Å, c=11.01±0.15 Å, α=111.70±0.50°, β=107.70±0.50°, and γ=90.00±0.50°, the sintered body has a triclinic crystal system, at least one metal in an atomic configuration below of the space group P-1 is any one of In, Ga and Al, or any two or more of In, Ga and Al, and is on identical atomic coordinates at a predetermined ratio, the atomic coordinates on which the at least one metal is arranged are in a range of x±0.01, y±0.01, and z±0.01, and atomic coordinates on which oxygen is arranged are in a range of x±0.01, y±0.01, and z±0.01, where atomic species: metal, atomic coordinates (x=0.04, y=0.36, z=0.87), atomic species: metal, atomic coordinates (x=0.13, y=0.12, z=0.62), atomic species: metal, atomic coordinates (x=0.21, y=0.85, z=0.39), atomic species: metal, atomic coordinates (x=0.23, y=0.11, z=0.97), atomic species: metal, atomic coordinates (x=0.29, y=0.64, z=0.11), atomic species: metal, atomic coordinates (x=0.46, y=0.12, z=0.63), atomic species: metal, atomic coordinates (x=0.58, y=0.14, z=0.01), atomic species: metal, atomic coordinates (x=0.62, y=0.64, z=0.11), atomic species: metal, atomic coordinates (x=0.69, y=0.18, z=0.32), atomic species: metal, atomic coordinates (x=0.09, y=0.88, z=0.03), atomic species: metal, atomic coordinates (x=0.02, y=0.13, z=0.30), atomic species: metal, atomic coordinates (x=0.06, y=0.61, z=0.46), atomic species: metal, atomic coordinates (x=0.15, y=0.40, z=0.19), atomic species: metal, atomic coordinates (x=0.26, y=0.36, z=0.54), atomic species: metal, atomic coordinates (x=0.34, y=0.13, z=0.30), atomic species: metal, atomic coordinates (x=0.41, y=0.61, z=0.45), atomic species: metal, atomic coordinates (x=0.48, y=0.40, z=0.23), atomic species: metal, atomic coordinates (x=0.84, y=0.39, z=0.23), atomic species: oxygen, atomic coordinates (x=0.02, y=0.73, z=0.36), atomic species: oxygen, atomic coordinates (x=0.03, y=0.45, z=0.29), atomic species: oxygen, atomic coordinates (x=0.05, y=0.02, z=0.40), atomic species: oxygen, atomic coordinates (x=0.10, y=0.74, z=0.65), atomic species: oxygen, atomic coordinates (x=0.10, y=0.23, z=0.06), atomic species: oxygen, atomic coordinates (x=0.12, y=0.51, z=0.09), atomic species: oxygen, atomic coordinates (x=0.12, y=0.47, z=0.57), atomic species: oxygen, atomic coordinates (x=0.13, y=0.79, z=0.17), atomic species: oxygen, atomic coordinates (x=0.19, y=0.21, z=0.84), atomic species: oxygen, atomic coordinates (x=0.20, y=0.23, z=0.36), atomic species: oxygen, atomic coordinates (x=0.25, y=0.66, z=0.49), atomic species: oxygen, atomic coordinates (x=0.27, y=0.02, z=0.12), atomic species: oxygen, atomic coordinates (x=0.30, y=0.26, z=0.65), atomic species: oxygen, atomic coordinates (x=0.33, y=0.44, z=0.29), atomic species: oxygen, atomic coordinates (x=0.38, y=0.02, z=0.40), atomic species: oxygen, atomic coordinates (x=0.39, y=0.73, z=0.35), atomic species: oxygen, atomic coordinates (x=0.41, y=0.24, z=0.07), atomic species: oxygen, atomic coordinates (x=0.43, y=0.47, z=0.57), atomic species: oxygen, atomic coordinates (x=0.46, y=0.51, z=0.11), atomic species: oxygen, atomic coordinates (x=0.47, y=0.79, z=0.15), atomic species: oxygen, atomic coordinates (x=0.50, y=0.25, z=0.36), atomic species: oxygen, atomic coordinates (x=0.64, y=0.03, z=0.12), atomic species: oxygen, atomic coordinates (x=0.66, y=0.34, z=0.23), atomic species: oxygen, atomic coordinates (x=0.72, y=0.03, z=0.40), atomic species: oxygen, atomic coordinates (x=0.78, y=0.51, z=0.12), atomic species: oxygen, atomic coordinates (x=0.80, y=0.25, z=0.06), and atomic species: oxygen, atomic coordinates (x=0.96, y=0.02, z=0.12).
5 . The sintered body according to claim 4 , wherein when a weight ratio between the Bixbyite structure containing the In element, the crystal structure belonging to the space group P1 or the space group P-1, and a crystal structure other than the Bixbyite structure and the crystal structure belonging to the space group P1 or P-1 is calculated by performing Rietveld analysis on a spectrum obtained by X-ray diffraction measurement on the sintered body, the weight ratio of a crystal of the Bixbyite structure containing the In element to a whole crystal of the sintered body is 70% or more.
6 . The sintered body according to claim 1 , wherein the sintered body comprises a H element, and an atomic concentration of the H element in the sintered body is 1×10 16 cm −3 or more and less than 1×10 18 cm −3 .
7 . The sintered body according to claim 1 , wherein the sintered body comprises a C element, and an atomic concentration of the C element in the sintered body is 1×10 16 cm −3 or more and less than 1×10 18 cm −3 .
8 . The sintered body according to claim 1 , wherein a bending strength of the sintered body is 190 MPa or more.
9 . A sputtering target using the sintered body of the oxide according to claim 1 .
10 . An oxide thin film using the sputtering target according to claim 9 .
11 . A thin film transistor comprising the oxide thin film according to claim 10 .
12 . An electronic device comprising the thin film transistor according to claim 11 .
13 . A method of producing a sintered body of an oxide comprising an In element, a Ga element, and an Al element, the method comprising: mixing and disintegrating indium oxide, gallium oxide, and aluminum oxide by bead milling, followed by granulation through a spray drying method to obtain granulated powder, and classifying the granulated powder; molding the granulated powder after the classification into a molded body; and sintering the molded body, wherein: in a field of view when the sintered body is observed with a scanning electron microscope, an area ratio of pores to an area of the field of view is 0.1% or less, and an atomic composition ratio of the In element and an atomic composition ratio of the Al element in the sintered body respectively satisfy a formula (1) and a formula (2) below, [ ln ] / ( [ ln ] + [ Ga ] + [ Al ] ) > 0.7 ( 1 ) [ Al ] / ( [ ln ] + [ Ga ] + [ Al ] ) > 0.01 . ( 2 )

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority under 35 U.S.C. § 371 to International Patent Application No. PCT/JP2023/008589, filed Mar. 7, 2023, which claims priority to and the benefit of Japanese Patent Application Nos. 2022-041918, filed Mar. 16, 2022, and 2022-104923, filed on Jun. 29, 2022. The contents of these applications are hereby incorporated by reference in their entireties. TECHNICAL FIELD The present invention relates to a sintered body, a sputtering target, an oxide thin film, a thin film transistor, an electronic device, and a method of producing a sintered body. BACKGROUND ART High-mobility thin film transistors (hereinafter the thin film transistor is occasionally referred to as a TFT) are required to provide high-definition displays for the next generation. Crystalline oxide semiconductors such as indium gallium oxide (IGO) are considered as semiconductor materials for use in the TFT. When an oxide semiconductor is used in a display, the TFT is obtained by sputtering with a sputtering target having the same atomic composition as an oxide sintered body. In order to provide large-size displays such as a TV, the manufacturing equipment is also larger from the viewpoint of manufacturing cost. The sintered body used for the sputtering target is also required to enable stable sputtering even in large equipment. For instance, Patent Literature 1 describes a sputtering target consisting essentially of an oxide of indium and gallium, or an oxide of indium, gallium and tin and/or aluminum. When the sputtering target described in Patent Literature 1 contains tin, the amount of tin is in a range from 100 to 10,000 ppm. When the sputtering target described in Patent Literature 1 contains aluminum, the amount of aluminum is in a range from 100 to 10,000 ppm. The sputtering target described in Patent Literature 1 is made of a sintered body having voids each having a volume of 14,000 μm3 or more in an amount of 0.03 volume % or less, in which one surface of the sintered body has an area of 25,000 mm2 or more and a thickness of 5 mm or more. If the sputtering target is made of a sintered body having an atomic composition ratio of an Al element of 1 atomic % or less and a void ratio of 0.03 volume % or less, as described in Patent Literature 1, sputtering can be stably performed in large sizes. Recent developments have made it clear that stability for the TFT producing process is required, e.g., the change in properties needs to be small for chemical vapor deposition (CVD), which is one of the processes after the formation of oxide semiconductor film. For instance, Patent Literature 2 describes a crystalline compound A represented by a composition formula (InxGayAlz)2O3 and having diffraction peaks in respective ranges of an incidence angle (2θ) observed by X-ray (Cu-Kα ray) diffraction measurement. In addition, Patent Literature 2 describes a sputtering target using an oxide sintered body that consists of the crystalline compound A. A sputtering target containing the crystalline compound A represented by the composition formula (InxGayAlz)2O3 as described in Patent Literature 2 can enable stable sputtering, is stable to the TFT producing process, and can meet the demand for TFT (thin film transistor) performance with high mobility. CITATION LIST Patent Literature(s) Patent Literature 1: Japan Patent No. 5997690Patent Literature 2: International Publication No. WO 2020/027243 SUMMARY OF THE INVENTION Problem(s) to be Solved by the Invention In recent years, panels for medium-size displays (notebooks and tablets) as well as large-size displays (TVs) have tended to be produced in large equipment with a glass substrate with dimensions of 2,200 mm×2,400 mm or larger. In addition, there are demands for higher definition and narrower bezels for medium-size display applications. To meet these demands, the TFT is required to have higher performance (high mobility and high optical reliability). Thus, the oxide sintered body used for the sputtering target is required to enable stable sputtering even in large equipment and to provide the TFT excellent in mobility, processability, and optical reliability, specifically, the TFT having high mobility and excellent in processability and in-plane uniformity control for performance. There is room for further improvement in conventional sintered bodies. An object of the invention is to provide a sintered body that enables stable sputtering even in large equipment and provides a TFT having high mobility and excellent in processability and in-plane uniformity of optical reliability; a sputtering target using the sintered body; an oxide thin film using the sputtering target; a thin film transistor including the oxide thin film; an electronic device including the thin film transistor; and a method of producing a sintered body that provides a TFT having high mobility and excellent in processability and in-plane uniformity of optical reliability