Semiconductor device
View Patent ↗An object is to stabilize electric characteristics of a semiconductor device including an oxide semiconductor to increase reliability. The semiconductor device includes an insulating film; a first metal oxide film on and in contact with the insulating film; an oxide semiconductor film partly in contact with the first metal oxide film; source and drain electrodes electrically connected to the oxide semiconductor film; a second metal oxide film partly in contact with the oxide semiconductor film; a gate insulating film on and in contact with the second metal oxide film; and a gate electrode over the gate insulating film.
1. A semiconductor device comprising:
a first metal oxide film over a substrate, the first metal oxide film comprising gallium;
an oxide semiconductor film in contact with the first metal oxide film;
source and drain electrodes in contact with the oxide semiconductor film;
a second metal oxide film in contact with the oxide semiconductor film, the second metal oxide film comprising gallium; and
a gate electrode over the second metal oxide film,
wherein an energy at a bottom of a conduction band of each of the first metal oxide film and the second metal oxide film is higher than an energy at a bottom of a conduction band of the oxide semiconductor film, and
wherein the second metal oxide film is in contact with a top surface of each of the source and drain electrodes.
2. The semiconductor device according to claim 1 , wherein each of the first metal oxide film and the second metal oxide film comprises a constituent element of the oxide semiconductor film.
3. The semiconductor device according to claim 1 , wherein a proportion of a constituent element of the first metal oxide film is equal to a proportion of a constituent element of the second metal oxide film.
4. The semiconductor device according to claim 1 , wherein an energy gap of each of the first metal oxide film and the second metal oxide film is larger than an energy gap of the oxide semiconductor film.
5. The semiconductor device according to claim 1 , wherein a side surface of the oxide semiconductor film is in contact with the second metal oxide film in a channel width direction.
6. The semiconductor device according to claim 1 , wherein the first metal oxide film is in contact with the second metal oxide film in a channel width direction.
7. A semiconductor device comprising:
a first metal oxide film over a substrate, the first metal oxide film comprising gallium;
an oxide semiconductor film in contact with the first metal oxide film;
source and drain electrodes in contact with the oxide semiconductor film;
a second metal oxide film in contact with the oxide semiconductor film, the second metal oxide film comprising gallium;
a gate insulating film over the second metal oxide film; and
a gate electrode over the gate insulating film,
wherein an energy at a bottom of a conduction band of each of the first metal oxide film and the second metal oxide film is higher than an energy at a bottom of a conduction band of the oxide semiconductor film, and
wherein the second metal oxide film is in contact with a top surface of each of the source and drain electrodes.
8. The semiconductor device according to claim 7 , wherein each of the first metal oxide film and the second metal oxide film comprises a constituent element of the oxide semiconductor film.
9. The semiconductor device according to claim 7 , wherein a proportion of a constituent element of the first metal oxide film is equal to a proportion of a constituent element of the second metal oxide film.
10. The semiconductor device according to claim 7 , wherein an energy gap of each of the first metal oxide film and the second metal oxide film is larger than an energy gap of the oxide semiconductor film.
11. The semiconductor device according to claim 7 , wherein a side surface of the oxide semiconductor film is in contact with the second metal oxide film in a channel width direction.
12. The semiconductor device according to claim 7 , wherein the first metal oxide film is in contact with the second metal oxide film in a channel width direction.