Semiconductor device
View Patent ↗An object is to provide a semiconductor device including an oxide semiconductor, which has stable electric characteristics and high reliability. In a transistor including an oxide semiconductor film, the oxide semiconductor film is subjected to dehydration or dehydrogenation performed by heat treatment. In addition, as a gate insulating film in contact with the oxide semiconductor film, an insulating film containing oxygen, preferably, a gate insulating film including a region containing oxygen with a higher proportion than the stoichiometric composition is used. Thus, oxygen is supplied from the gate insulating film to the oxide semiconductor film. Further, a metal oxide film is used as part of the gate insulating film, whereby reincorporation of an impurity such as hydrogen or water into the oxide semiconductor is suppressed.
1. A semiconductor device comprising:
a first gate electrode;
a first metal oxide film over and in contact with the first gate electrode;
a first insulating film containing oxygen over the first metal oxide film;
an oxide semiconductor film over and in contact with the first insulating film containing oxygen;
a second insulating film containing oxygen over the oxide semiconductor film;
a second metal oxide film over the second insulating film containing oxygen, and
a second gate electrode over the second metal oxide film,
wherein the first metal oxide film contains at least one of aluminum and gallium,
wherein the first metal oxide film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the first metal oxide film, and
wherein the second metal oxide film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the second metal oxide film.
2. The semiconductor device according to claim 1 ,
wherein the first insulating film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the first insulating film, and
wherein the second insulating film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the second insulating film.
3. The semiconductor device according to claim 1 ,
wherein the first metal oxide film contains at least one of gallium oxide, aluminum oxide, aluminum gallium oxide, and gallium aluminum oxide, and
wherein the second metal oxide film contains at least one of gallium oxide, aluminum oxide, aluminum gallium oxide, and gallium aluminum oxide.
4. The semiconductor device according to claim 1 , wherein the first insulating film containing oxygen and the second insulating film containing oxygen are partly in contact with each other.
5. The semiconductor device according to claim 1 , wherein the oxide semiconductor film is an i-type oxide semiconductor.
6. The semiconductor device according to claim 1 , wherein the semiconductor device is one of a laptop personal computer, a portable information terminal, an electronic book reader, a mobile phone, a digital video camera, and a television set.
7. A semiconductor device comprising:
a first gate electrode;
a first metal oxide film over and in contact with the first gate electrode;
a first insulating film containing oxygen over the first metal oxide film;
an oxide semiconductor film over and in contact with the first insulating film containing oxygen;
a source electrode and a drain electrode in contact with the oxide semiconductor film;
a second insulating film containing oxygen over and in contact with the oxide semiconductor film;
a second metal oxide film over the second insulating film containing oxygen, and
a second gate electrode over the second metal oxide film,
wherein the first metal oxide film contains at least one of aluminum and gallium,
wherein the first metal oxide film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the first metal oxide film, and
wherein the second metal oxide film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the second metal oxide film.
8. The semiconductor device according to claim 7 ,
wherein the first insulating film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the first insulating film, and
wherein the second insulating film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the second insulating film.
9. The semiconductor device according to claim 7 ,
wherein the first metal oxide film contains at least one of gallium oxide, aluminum oxide, aluminum gallium oxide, and gallium aluminum oxide, and
wherein the second metal oxide film contains at least one of gallium oxide, aluminum oxide, aluminum gallium oxide, and gallium aluminum oxide.
10. The semiconductor device according to claim 7 , wherein the first insulating film containing oxygen and the second insulating film containing oxygen are partly in contact with each other.
11. The semiconductor device according to claim 7 , wherein the oxide semiconductor film is an i-type oxide semiconductor.
12. The semiconductor device according to claim 7 , wherein the semiconductor device is one of a laptop personal computer, a portable information terminal, an electronic book reader, a mobile phone, a digital video camera, and a television set.
13. A semiconductor device comprising:
a first gate electrode;
a first metal oxide film over the first gate electrode;
a first insulating film containing oxygen over the first metal oxide film;
an oxide semiconductor film over and in contact with the first insulating film containing oxygen;
a source electrode and a drain electrode in contact with the oxide semiconductor film;
a second insulating film containing oxygen over and in contact with the oxide semiconductor film;
a second metal oxide film over the second insulating film containing oxygen, and
a second gate electrode over the second metal oxide film,
wherein each of the first metal oxide film and the second metal oxide film contains gallium.
14. The semiconductor device according to claim 13 ,
wherein the first metal oxide film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the first metal oxide film, and
wherein the second metal oxide film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the second metal oxide film.
15. The semiconductor device according to claim 13 ,
wherein the first insulating film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the first insulating film, and
wherein the second insulating film comprises a region containing oxygen at a ratio exceeding a ratio of oxygen in a stoichiometric composition of the second insulating film.
16. The semiconductor device according to claim 13 ,
wherein the first metal oxide film contains at least one of gallium oxide, aluminum gallium oxide, and gallium aluminum oxide, and
wherein the second metal oxide film contains at least one of gallium oxide, aluminum gallium oxide, and gallium aluminum oxide.
17. The semiconductor device according to claim 13 , wherein the first insulating film containing oxygen and the second insulating film containing oxygen are partly in contact with each other.
18. The semiconductor device according to claim 13 , wherein the oxide semiconductor film is an i-type oxide semiconductor.
19. The semiconductor device according to claim 13 , wherein the semiconductor device is one of a laptop personal computer, a portable information terminal, an electronic book reader, a mobile phone, a digital video camera, and a television set.