Semiconductor device and method for manufacturing semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorShunpei YAMAZAKI
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Abstract
To provide a transistor including an oxide semiconductor layer and having electric characteristics required depending on an intended use and provide a semiconductor device including the transistor, in a transistor in which a semiconductor layer, source and drain electrode layers, a gate insulating film, and a gate electrode are stacked in this order over an oxide semiconductor insulating film, an oxide semiconductor stack layer which includes at least two oxide semiconductor layers with energy gaps different from each other and a mixed region therebetween is used as the semiconductor layer.
Claims20
(canceled)
A semiconductor device comprising:
- a first oxide semiconductor layer;
- a second oxide semiconductor layer over the first oxide semiconductor layer;
- a third oxide semiconductor layer over the second oxide semiconductor layer;
- and
- a gate electrode layer comprising a region overlapping with the first oxide semiconductor layer, the second oxide semiconductor layer and the third oxide semiconductor layer,
- wherein energy at a bottom of a conduction band of the second oxide semiconductor layer is lower than energy at a bottom of a conduction band of the first oxide semiconductor layer and energy at a bottom of a conduction band of the third oxide semiconductor layer,
- wherein the at bottom of the conduction band of the first oxide semiconductor layer and the bottom of the conduction band of the second oxide semiconductor layer are continuously connected in an energy band diagram, and
- wherein the bottom of the conduction band of the second oxide semiconductor layer and the bottom of the conduction band of the third oxide semiconductor layer are continuously connected in the energy band diagram.
A semiconductor device comprising:
- a first oxide semiconductor layer;
- a second oxide semiconductor layer over the first oxide semiconductor layer;
- a third oxide semiconductor layer over the second oxide semiconductor layer;
- a source electrode layer in contact with the third oxide semiconductor layer;
- a drain electrode layer in contact with the third oxide semiconductor layer;
- and
- a gate electrode layer comprising a region overlapping with the first oxide semiconductor layer, the second oxide semiconductor layer and the third oxide semiconductor layer,
- wherein energy at a bottom of a conduction band of the second oxide semiconductor layer is lower than energy at a bottom of a conduction band of the first oxide semiconductor layer and energy at a bottom of a conduction band of the third oxide semiconductor layer,
- wherein the bottom of the conduction band of the first oxide semiconductor layer and the bottom of the conduction band of the second oxide semiconductor layer are continuously connected in an energy band diagram,
- wherein the bottom of the conduction band of the second oxide semiconductor layer and the bottom of the conduction band of the third oxide semiconductor layer are continuously connected in the energy band diagram, and
- wherein the third oxide semiconductor layer covers side surfaces of the second oxide semiconductor layer.
A semiconductor device comprising:
- a first oxide semiconductor layer;
- a second oxide semiconductor layer over the first oxide semiconductor layer;
- a source electrode layer in contact with the second oxide semiconductor layer;
- a drain electrode layer in contact with the second oxide semiconductor layer;
- and
- a gate electrode layer over the first oxide semiconductor layer and the second oxide semiconductor layer,
- wherein energy gaps of the first oxide semiconductor layer and the second oxide semiconductor layer are different from each other,
- wherein the second oxide semiconductor layer covers side surfaces of the first oxide semiconductor layer, and
- wherein a region of the first oxide semiconductor layer and the second oxide semiconductor layer, which does not overlap with the gate electrode layer, contains a dopant.
Dependencies are inferred from the claim text.