Oxide semiconductor film and semiconductor device
To provide a novel oxide semiconductor film. The oxide semiconductor film includes In, M, and Zn. The M is Al, Ga, Y, or Sn. In the case where the proportion of In in the oxide semiconductor film is 4, the proportion of M is greater than or equal to 1.5 and less than or equal to 2.5 and the proportion of Zn is greater than or equal to 2 and less than or equal to 4.
1. An oxide semiconductor film comprising In, M, and Zn,
wherein the oxide semiconductor film has a composition in a neighborhood of a solid solution range of an In 1+x M 1−x O 3 (ZnO) y structure,
wherein the M is Al, Ga, Y, or Sn,
wherein x satisfies 0<x<0.5,
wherein y is approximately 1,
wherein the oxide semiconductor film is formed with a sputtering apparatus,
wherein the sputtering apparatus comprises a polycrystalline metal oxide target,
wherein the polycrystalline metal oxide target has a composition in a neighborhood of In:M:Zn=4:2:4.1, and
wherein in the case where a proportion of the In of the polycrystalline metal oxide target is 4, a proportion of the M is greater than or equal to 1.5 and less than or equal to 2.5 and a proportion of the Zn is greater than or equal to 3.1 and less than or equal to 5.1.
2. The oxide semiconductor film according to claim 1 ,
wherein the oxide semiconductor film has an atomic ratio in a neighborhood of In:M:Zn=4:2:3, and
wherein in the case where a proportion of the In is 4, a proportion of the M is greater than or equal to 1.5 and less than or equal to 2.5 and a proportion of the Zn is greater than or equal to 2 and less than or equal to 4.
3. The oxide semiconductor film according to claim 1 ,
wherein the oxide semiconductor film comprises a crystal part, and
wherein the crystal part has c-axis alignment.
4. The oxide semiconductor film according to claim 1 , wherein the oxide semiconductor film comprises a region with a hydrogen concentration of lower than 1×10 20 atoms/cm 3 .
5. The oxide semiconductor film according to claim 1 , wherein the oxide semiconductor film comprises a region where the In, the M, the Zn, and O atoms in total account for 99.97 atomic % or more.
6. The oxide semiconductor film according to claim 1 , wherein the oxide semiconductor film comprises a region where Fe, Ni, and Si atoms in total account for lower than 0.03 atomic %.
7. A semiconductor device comprising the oxide semiconductor film according to claim 1 .
8. An oxide semiconductor film comprising:
a first film; and
a second film over the first film,
wherein each of the first film and the second film comprises In, M, and Zn,
wherein the M is Al, Ga, Y, or Sn,
wherein the first film has a composition in a neighborhood of a solid solution range of an In 1+x M 1−x O 3 (ZnO) y structure,
wherein the second film comprises a region having a composition in a neighborhood of a solid solution range of an In 1+v M 1−v O 3 (ZnO) w structure and having a smaller proportion of indium atoms than the first film,
wherein x satisfies 0<x<0.5,
wherein y is approximately 1,
wherein v satisfies −0.2≤v<0.2,
wherein w is approximately 1,
wherein the first film comprises a region where the In, the M, the Zn, and O atoms in total account for 99.97 atomic % or more,
wherein the first film and the second film are formed by a sputtering apparatus,
wherein the sputtering apparatus comprises a first polycrystalline metal oxide target and a second polycrystalline metal oxide target,
wherein the first polycrystalline metal oxide target has a composition in a neighborhood of In:M:Zn=4:2:4.1,
wherein the second polycrystalline metal oxide target has a composition in a neighborhood of In:M:Zn=1:1:1.2, and
wherein in the case where a proportion of the In of the first polycrystalline metal oxide target is 4, a proportion of the M is greater than or equal to 1.5 and less than or equal to 2.5 and a proportion of the Zn is greater than or equal to 3.1 and less than or equal to 5.1.
9. The oxide semiconductor film according to claim 8 ,
wherein x is approximately 0.33, and
wherein v is approximately 0.
10. The oxide semiconductor film according to claim 8 ,
wherein the first film has an atomic ratio in a neighborhood of In:M:Zn=4:2:3,
wherein the second film has an atomic ratio in a neighborhood of In:M:Zn=1:1:1, and
wherein in the case where a proportion of the In of the first film is 4, a proportion of the M is greater than or equal to 1.5 and less than or equal to 2.5 and a proportion of the Zn is greater than or equal to 2 and less than or equal to 4.
11. The oxide semiconductor film according to claim 8 ,
wherein the first film comprises a crystal part, and
wherein the crystal part has c-axis alignment.
12. The oxide semiconductor film according to claim 8 , wherein the first film comprises a region with a hydrogen concentration of lower than 1×10 20 atoms/cm 3 .
13. The oxide semiconductor film according to claim 8 , wherein the first film comprises a region where Fe, Ni, and Si atoms in total account for lower than 0.03 atomic %.
14. A semiconductor device comprising the oxide semiconductor film according to claim 8 .