Semiconductor device and manufacturing method of the same
One object is to provide a semiconductor device including an oxide semiconductor, which has stable electric characteristics and high reliability. Another object is to manufacture a highly reliable semiconductor device in a high yield. In a top-gate staggered transistor including an oxide semiconductor film, as a first gate insulating film in contact with the oxide semiconductor film, a silicon oxide film is formed by a plasma CVD method with use of a deposition gas containing silicon fluoride and oxygen; and as a second gate insulating film stacked over the first gate insulating film, a silicon oxide film is formed by a plasma CVD method with use of a deposition gas containing silicon hydride and oxygen.
1. A semiconductor device comprising:
an insulating film;
a source electrode layer and a drain electrode layer over the insulating film;
an island-shaped oxide semiconductor film over the insulating film, the source electrode layer, and the drain electrode layer;
an island-shaped first gate insulating film over and in contact with the island-shaped oxide semiconductor film;
a second gate insulating film over the insulating film, the source electrode layer, the drain electrode layer, the island-shaped oxide semiconductor film, and the island-shaped first gate insulating film; and
a gate electrode layer over the second gate insulating film,
wherein the island-shaped first gate insulating film includes a silicon oxide film containing fluorine,
wherein the second gate insulating film contains hydrogen,
wherein a hydrogen concentration of the second gate insulating film is higher than a hydrogen concentration of the island-shaped first gate insulating film, and
wherein a width of the island-shaped oxide semiconductor film is smaller than a width of the gate electrode layer in a direction perpendicular to a direction from the source electrode layer to the drain electrode layer.
2. The semiconductor device according to claim 1 , wherein a thickness of the island-shaped first gate insulating film is smaller than a thickness of the second gate insulating film.
3. The semiconductor device according to claim 1 , wherein a thickness of the island-shaped first gate insulating film is greater than or equal to 1 nm and less than or equal to 10 nm.
4. The semiconductor device according to claim 1 ,
wherein a hydrogen concentration in the island-shaped first gate insulating film is lower than a fluorine concentration in the island-shaped first gate insulating film,
wherein the fluorine concentration is greater than or equal to 1×10 20 atoms/cm 3 , and
wherein the hydrogen concentration is less than 1×10 20 atoms/cm 3 .
5. The semiconductor device according to claim 1 ,
wherein a hydrogen concentration in the second gate insulating film is higher than a fluorine concentration in the second gate insulating film,
wherein the fluorine concentration is less than 1×10 20 atoms/cm 3 , and
wherein the hydrogen concentration is greater than or equal to 1×10 20 atoms/cm 3 .
6. A semiconductor device comprising:
an insulating film;
a source electrode layer and a drain electrode layer over the insulating film;
an island-shaped oxide semiconductor film over the insulating film, the source electrode layer, and the drain electrode layer;
an island-shaped first gate insulating film over and in contact with the island-shaped oxide semiconductor film;
a second gate insulating film over the insulating film, the source electrode layer, the drain electrode layer, the island-shaped oxide semiconductor film, and the island-shaped first gate insulating film; and
a gate electrode layer over the second gate insulating film,
wherein the island-shaped first gate insulating film includes a silicon oxide film containing fluorine,
wherein the second gate insulating film contains hydrogen,
wherein a hydrogen concentration of the second gate insulating film is higher than a hydrogen concentration of the island-shaped first gate insulating film,
wherein the insulating film includes a silicon oxide film containing fluorine, and
wherein a width of the island-shaped oxide semiconductor film is smaller than a width of the gate electrode layer in a direction perpendicular to a direction from the source electrode layer to the drain electrode layer.
7. The semiconductor device according to claim 6 , wherein a thickness of the island-shaped first gate insulating film is smaller than a thickness of the second gate insulating film.
8. The semiconductor device according to claim 6 , wherein a thickness of the island-shaped first gate insulating film is greater than or equal to 1 nm and less than or equal to 10 nm.
9. The semiconductor device according to claim 6 ,
wherein a hydrogen concentration in the island-shaped first gate insulating film is lower than a fluorine concentration in the island-shaped first gate insulating film,
wherein the fluorine concentration is greater than or equal to 1×10 20 atoms/cm 3 , and
wherein the hydrogen concentration is less than 1×10 20 atoms/cm 3 .
10. The semiconductor device according to claim 6 ,
wherein a hydrogen concentration in the second gate insulating film is higher than a fluorine concentration in the second gate insulating film,
wherein the fluorine concentration is less than 1×10 20 atoms/cm 3 , and
wherein the hydrogen concentration is greater than or equal to 1×10 20 atoms/cm 3 .
11. A semiconductor device comprising:
an insulating film;
a source electrode layer and a drain electrode layer over the insulating film;
an island-shaped oxide semiconductor film over the insulating film, the island-shaped oxide semiconductor film electrically connected to the source electrode layer and the drain electrode layer;
a first gate insulating film in contact with the island-shaped oxide semiconductor film;
a second gate insulating film in contact with the first gate insulating film; and
a gate electrode layer, wherein the gate electrode layer and the island-shaped oxide semiconductor film overlap with each other,
wherein the first gate insulating film includes a silicon oxide film containing fluorine,
wherein the second gate insulating film contains hydrogen and fluorine,
wherein a hydrogen concentration of the second gate insulating film is higher than a hydrogen concentration of the first gate insulating film, and
wherein a width of the island-shaped oxide semiconductor film is smaller than a width of the gate electrode layer in a direction perpendicular to a direction from the source electrode layer to the drain electrode layer.
12. The semiconductor device according to claim 11 , wherein the first gate insulating film is island-shaped.
13. The semiconductor device according to claim 11 , wherein a thickness of the first gate insulating film is smaller than a thickness of the second gate insulating film.
14. The semiconductor device according to claim 11 , wherein a thickness of the first gate insulating film is greater than or equal to 1 nm and less than or equal to 10 nm.
15. The semiconductor device according to claim 11 ,
wherein the hydrogen concentration of the first gate insulating film is lower than a fluorine concentration of the first gate insulating film,
wherein the fluorine concentration of the first gate insulating film is greater than or equal to 1×10 20 atoms/cm 3 , and
wherein the hydrogen concentration of the first gate insulating film is less than 1×10 20 atoms/cm 3 .
16. The semiconductor device according to claim 11 ,
wherein the hydrogen concentration of the second gate insulating film is higher than a fluorine concentration of the second gate insulating film,
wherein the fluorine concentration of the second gate insulating film is less than 1×10 20 atoms/cm 3 , and
wherein the hydrogen concentration of the second gate insulating film is greater than or equal to 1×10 20 atoms/cm 3 .