Oxide semiconductor film and semiconductor device
To provide an oxide semiconductor film having stable electric conductivity and a highly reliable semiconductor device having stable electric characteristics by using the oxide semiconductor film. The oxide semiconductor film contains indium (In), gallium (Ga), and zinc (Zn) and includes a c-axis-aligned crystalline region aligned in the direction parallel to a normal vector of a surface where the oxide semiconductor film is formed. Further, the composition of the c-axis-aligned crystalline region is represented by In 1+δ Ga 1−δ O 3 (ZnO) m (0<δ<1 and m=1 to 3 are satisfied), and the composition of the entire oxide semiconductor film including the c-axis-aligned crystalline region is represented by In x Ga y O 3 (ZnO) m (0<x<2, 0<y<2, and m=1 to 3 are satisfied).
1. An oxide semiconductor film comprising:
a crystalline region in an upper portion of the oxide semiconductor film, the crystalline region comprising a crystal,
wherein the crystalline region is represented by In 1+δ Ga 1−δ O 3 (ZnO) m ,
wherein 0<δ<1 and m=1 to 3 are satisfied, and
wherein a composition ratio of the crystalline region is different from a composition ratio of the oxide semiconductor film.
2. The oxide semiconductor film according to claim 1 , wherein the oxide semiconductor film has no signal assigned to oxygen vacancies in an electron spin resonance measurement.
3. The oxide semiconductor film according to claim 1 , wherein the crystalline region is formed by a heat treatment.
4. The oxide semiconductor film according to claim 1 ,
wherein the oxide semiconductor film is represented by In x Ga y (ZnO) m , and
wherein 0<x<2, 0<y<2, and m=1 to 3 are satisfied.
5. The oxide semiconductor film according to claim 1 , wherein a c-axis of the crystal is oriented substantially in a direction parallel to a normal vector of a surface where the oxide semiconductor film is formed.
6. A semiconductor device comprising:
a gate electrode;
a first insulating film over the gate electrode;
an oxide semiconductor film over the first insulating film; and
a second insulating film over the oxide semiconductor film,
wherein the oxide semiconductor film comprises a crystalline region in an upper portion of the oxide semiconductor film,
wherein the crystalline region is represented by In 1+δ Ga 1−δ O 3 (ZnO) m ,
wherein 0<δ<1 and m=1 to 3 are satisfied, and
wherein a composition ratio of the crystalline region is different from a composition ratio of the oxide semiconductor film.
7. The semiconductor device according to claim 6 , wherein the oxide semiconductor film has no signal assigned to oxygen vacancies in an electron spin resonance measurement.
8. The semiconductor device according to claim 6 , wherein the crystalline region is formed by a heat treatment.
9. The semiconductor device according to claim 6 ,
wherein the oxide semiconductor film is represented by In x Ga y O 3 (ZnO) m , and
wherein 0<x<2, 0<y<2, and m=1 to 3 are satisfied.
10. A semiconductor device comprising:
a first insulating film;
an oxide semiconductor film over the first insulating film;
a second insulating film over the oxide semiconductor film; and
a gate electrode over the second insulating film,
wherein the oxide semiconductor film comprises a crystalline region in an upper portion of the oxide semiconductor film,
wherein the crystalline region is represented by In 1+δ Ga 1−δ O 3 (ZnO) m ,
wherein 0<δ<1 and m=1 to 3 are satisfied, and
wherein a composition ratio of the crystalline region is different from a composition ratio of the oxide semiconductor film.
11. The semiconductor device according to claim 10 , wherein the oxide semiconductor film has no signal assigned to oxygen vacancies in an electron spin resonance measurement.
12. The semiconductor device according to claim 10 , wherein the crystalline region is formed by a heat treatment.
13. The semiconductor device according to claim 10 ,
wherein the oxide semiconductor film is represented by In x Ga y O 3 (ZnO) m , and
wherein 0<x<2, 0<y<2, and m=1 to 3 are satisfied.