Sputtering target and thin film transistor equipped with same
A sintered body including an oxide that includes In, Ga and Zn at the following atomic ratio and includes a compound having as a main component a homologous crystal structure represented by InGaO 3 (ZnO): 0.28≦Zn/(In+Zn+Ga)≦0.38 0.18≦Ga/(In+Zn+Ga)≦0.28.
1. A sintered body comprising an oxide that comprises In, Ga and Zn at the following atomic ratio and comprises as a main component a compound having as a main component a homologous crystal structure represented by InGaO 3 (ZnO):
0.28≦Zn/(In+Zn+Ga)≦0.38
0.18≦Ga/(In+Zn+Ga)≦0.28,
wherein the sintered body has a relative density of 90% or more, a specific resistance of 15 mΩcm or less, a surface roughness of 2 μm or less and an average crystal diameter of 10 μm or less.
2. The sintered body according to claim 1 , wherein crystals of compounds represented by Ga 2 O 3 , ZnGa 2 O 4 , ZnO, In 2 O 3 , InGaO 3 and In 2 O 3 (ZnO) 3 are not observed in an analysis by X-ray diffraction.
3. The sintered body according to claim 1 , wherein the atomic ratio of In, Ga and Zn of the oxide further satisfies the following formula:
0.59≦In/(In+Ga).
4. The sintered body according to claim 1 , wherein the oxide consists essentially of In, Ga, Zn and O.
5. A sputtering target comprising the sintered body according to claim 1 , which has a relative density of 90% or more, a specific resistance of 15 mΩcm or less, a surface roughness of 2 μm or less and an average crystal diameter of 10 μm or less.
6. A method for producing a thin film transistor comprising the step of forming a semiconductor layer using the sputtering target according to claim 5 .
7. A thin film transistor prepared by using the sputtering target according to claim 5 .
8. The sputtering target according to claim 5 , which has a transverse rupture strength of 58 MPa or more.
9. The sintered body according to claim 1 , which has a transverse rupture strength of 58 MPa or more.