Sputtering target
A sputtering target comprising an oxide sintered body that includes an indium element, a tin element and a zinc element, wherein the oxide sintered body includes one or more selected from a hexagonal layered compound represented by In 2 O 3 (ZnO) m , a hexagonal layered compound represented by InXO 3 (ZnO) n , a rutile structure compound represented by SnO 2 and an ilmenite structure compound represented by ZnSnO 3 , and a spinel structure compound represented by Zn 2 SnO 4 , in the formulas, X is a metal element that can form a hexagonal layered compound together with an indium element and a zinc element, m is an integer of 1 or more and n is an integer of 1 or more, and an agglomerate of the spinel structure compound is 5% or less of the entire sintered body.
1. A sputtering target comprising an oxide sintered body that comprises an indium element, a tin element and a zinc element, wherein
the atomic ratio of the indium element, the tin element and the zinc element is within the following range,
0.01 ≤In/(In+Sn+Zn)0.35
the oxide sintered body comprises one or more selected from a hexagonal layered compound represented by In 2 O 3 (ZnO) m , a hexagonal layered compound represented by InXO 3 (ZnO) n , a rutile structure compound represented by SnO 2 and an ilmenite structure compound represented by ZnSnO 3 , and a spinel structure compound represented by Zn 2 SnO 4 ,
in the formulas, X is a metal element that can form a hexagonal layered compound together with an indium element and a zinc element, m is an integer of 1 or more and n is an integer of 1 or more, and
an agglomerate of the spinel structure compound is 5% or less of the entire sintered body, and the three-point bending strength of the oxide sintered body is 120 MPa or more, wherein the hexagonal layered compound represented by In 2 O 3 (ZnO) m comprises needle-like crystals having an aspect ratio of 3 or more in an amount of 10% or more.
2. The sputtering target according to claim 1 , wherein the oxide sintered body comprises the hexagonal layered compound represented by In 2 O 3 (ZnO).
3. The sputtering target according to claim 1 , wherein the oxide sintered body comprises a gallium element.
4. The sputtering target according to claim 3 , wherein the gallium element is in a solid solution state in one or more selected from the hexagonal layered compound represented by In 2 O 3 (ZnO) m , the hexagonal layered compound represented by InXO 3 (ZnO) n , the rutile structure compound and the spinel structure compound.
5. The sputtering target according to claim 3 , wherein the atomic ratio of the indium element, the tin element, the zinc element and the gallium element is within the following range:
0.01≤In/(In+Sn+Zn+Ga)≤0.35
0.15≤Sn/(In+Sn+Zn+Ga)≤0.55
0.3≤Zn/(In+Sn+Zn+Ga)≤0.7
0.01≤Ga/(In+Sn+Zn+Ga)≤0.35.
6. The sputtering target according to claim 5 , wherein the atomic ratio of the total of the indium element and the gallium element is within the following range:
0.02≤(In+Ga)/(In+Sn+Zn)≤0.35.
7. The sputtering target according to claim 1 , wherein X is a gallium element.
8. The sputtering target according to claim 1 , wherein the oxide sintered body comprises the hexagonal layered compound represented by InXO 3 (ZnO) n .
9. The sputtering target according to claim 1 , wherein the oxide sintered body does not comprise a bixbyite structure.
10. The sputtering target according to claim 1 , wherein the atomic ratio of the indium element, the tin element and the zinc element is within the following range:
0.01≤In/(In+Sn+Zn)≤0.35
0.15≤Sn/(In+Sn+Zn)≤0.55
0.3≤Zn/(In+Sn+Zn)≤0.7.
11. The sputtering target according to claim 10 , wherein the atomic ratio of the indium element, the tin element and the zinc element is within the following range:
0.15≤In/(In+Sn+Zn)≤0.35
0.15≤Sn/(In+Sn+Zn)≤0.25
0.5≤Zn/(In+Sn+Zn)≤0.7.
12. A method for producing the sputtering target according to claim 1 comprising:
pulverizing and mixing raw material compounds by using a planetary ball mill at an integrated power of 200 Wh or more to produce powder mixture;
granulating the powder mixture to produce granulated powder having a BET surface area of 10 m 2 /g or more and a median diameter obtained by means of a laser diffraction particle size analyzer of 1 μm or more and 100 μm or less;
forming the granulated powder to produce a formed body; and
sintering the formed body by retaining at a temperature of 1300° C. or higher for 12 hours or longer to obtain the oxide sintered body.
13. A sputtering target that is produced by the method according to claim 12 .
14. An oxide semiconductor thin film formed by a sputtering method by using the sputtering target according to claim 1 .
15. A thin film transistor comprising the oxide semiconductor thin film according to claim 14 .
16. An electronic apparatus comprising the thin film transistor according to claim 15 .