Semiconductor device
A transistor includes a multilayer film in which an oxide semiconductor film and an oxide film are stacked, a gate electrode, and a gate insulating film. The multilayer film overlaps with the gate electrode with the gate insulating film interposed therebetween. The multilayer film has a shape having a first angle between a bottom surface of the oxide semiconductor film and a side surface of the oxide semiconductor film and a second angle between a bottom surface of the oxide film and a side surface of the oxide film. The first angle is acute and smaller than the second angle. Further, a semiconductor device including such a transistor is manufactured.
1. A semiconductor device comprising:
an insulating surface;
a first oxide film over and in contact with the insulating surface, the first oxide film comprising indium and gallium;
a second oxide film over and in contact with the first oxide film, the second oxide film comprising indium and gallium; and
a conductive film over and in contact with a top surface of the second oxide film, the conductive film being in contact with a side surface of the first oxide film and a side surface of the second oxide film,
wherein a length of the side surface of the first oxide film is larger than a length of the side surface of the second oxide film in a cross-sectional view, and
wherein the first oxide film is crystalline.
2. The semiconductor device according to claim 1 , further comprising a gate electrode under the first oxide film.
3. The semiconductor device according to claim 1 , further comprising a gate electrode over the second oxide film.
4. A semiconductor device comprising:
an insulating surface;
a first oxide film over and in contact with the insulating surface, the first oxide film comprising indium, gallium and zinc;
a second oxide film over and in contact with the first oxide film, the second oxide film comprising indium, gallium and zinc; and
a conductive film over and in contact with a top surface of the second oxide film, the conductive film being in contact with a side surface of the first oxide film and a side surface of the second oxide film,
wherein a length of the side surface of the first oxide film is larger than a length of the side surface of the second oxide film in a cross-sectional view.
5. The semiconductor device according to claim 4 , further comprising a gate electrode under the first oxide film.
6. The semiconductor device according to claim 4 , further comprising a gate electrode over the second oxide film.
7. The semiconductor device according to claim 4 , wherein the first oxide film is crystalline.
8. A semiconductor device comprising:
an insulating surface;
a first oxide film over and in contact with the insulating surface, the first oxide film comprising indium;
a second oxide film over and in contact with the first oxide film, the second oxide film comprising indium; and
a conductive film over and in contact with a top surface of the second oxide film, the conductive film being in contact with a side surface of the first oxide film and a side surface of the second oxide film,
wherein a length of the side surface of the first oxide film is larger than a length of the side surface of the second oxide film in a cross-sectional view, and
wherein the first oxide film is crystalline.
9. The semiconductor device according to claim 8 , further comprising a gate electrode under the first oxide film.
10. The semiconductor device according to claim 8 , further comprising a gate electrode over the second oxide film.