Semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorShunpei Yamazaki
Life of this patent
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Abstract
A semiconductor device having a structure which can prevent a decrease in electrical characteristics, which becomes more significant with miniaturization of a transistor, is provided. In addition, a highly reliable semiconductor device is provided. The semiconductor device includes a first gate electrode layer, a second gate electrode layer, and a third gate electrode layer, which are each provided separately. The first gate electrode layer overlaps with an oxide semiconductor layer. The second gate electrode layer partly covers one end portion of the oxide semiconductor layer in the channel width direction. The third gate electrode layer partly covers the other end portion of the oxide semiconductor layer in the channel width direction.
Claims12
A semiconductor device comprising:
- an oxide semiconductor layer over a substrate;
- a source electrode and a drain electrode in contact with the oxide semiconductor layer;
- a gate insulating film over the oxide semiconductor layer, the source electrode, and the drain electrode;
- and
- a first gate electrode, a second gate electrode, and a third gate electrode over the gate insulating film,
- wherein the first gate electrode, the second gate electrode, and the third gate electrode are separated from one another,
- wherein the first gate electrode overlaps with the oxide semiconductor layer,
- wherein the second gate electrode partly covers one end portion of the oxide semiconductor layer in a channel width direction, and
- wherein the third gate electrode partly covers the other end portion of the oxide semiconductor layer in the channel width direction.
A semiconductor device comprising:
- a first oxide semiconductor layer over a substrate;
- a second oxide semiconductor layer over the first oxide semiconductor layer;
- a first source electrode layer and a first drain electrode layer in contact with the second oxide semiconductor layer;
- a third oxide semiconductor layer over the second oxide semiconductor layer, the first source electrode layer, and the first drain electrode layer;
- a second source electrode layer covering the first source electrode layer and in contact with the first source electrode layer and the third oxide semiconductor layer;
- a second drain electrode layer covering the first drain electrode layer and in contact with the first drain electrode layer and the third oxide semiconductor layer;
- a gate insulating film over the third oxide semiconductor layer, the second source electrode layer, and the second drain electrode layer;
- and
- a first gate electrode, a second gate electrode, and a third gate electrode over the gate insulating film,
- wherein the first gate electrode, the second gate electrode, and the third gate electrode are separated from one another,
- wherein the first gate electrode overlaps with the first oxide semiconductor layer and the second oxide semiconductor layer,
- wherein the second gate electrode partly covers one end portion of each of the first oxide semiconductor layer and the second oxide semiconductor layer in a channel width direction, and
- wherein the third gate electrode partly covers the other end portion of each of the first oxide semiconductor layer and the second oxide semiconductor layer in the channel width direction.
Dependencies are inferred from the claim text.