Semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei YAMAZAKI, Atsuo ISOBE, Yuki HATA, Suguru HONDO
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Abstract
A transistor including an oxide semiconductor and having favorable operation characteristics is provided. Further, by using the transistor, a semiconductor having improved operation characteristics can be provided. In planar view, one of a source electrode and a drain electrode of the transistor is surrounded by a ring-shaped gate electrode. Further, in planar view, one of the source electrode and the drain electrode of the transistor is surrounded by a channel formation region. Accordingly, the source electrode is not electrically connected to the drain electrode through a parasitic channel generated in an end portion of an island-shaped oxide semiconductor layer.
Claims21
(canceled)
A semiconductor device comprising:
- an insulating layer;
- a semiconductor layer having an island shape over the insulating layer;
- a first electrode that is over the semiconductor layer and serves as one of source and drain electrodes;
- a second electrode that covers at least a part of an outer edge of the semiconductor layer and serves as the other of the source and drain electrodes;
- a gate insulating layer covering the semiconductor layer and the first and second electrodes;
- and
- a gate electrode over the gate insulating layer,
- wherein the gate electrode has a ring shape that surrounds an entire outer edge of the first electrode in a top view, and
- wherein the second electrode is located outside an outer edge of the gate electrode to surround at least a part of the outer edge of the gate electrode in the top view.
A semiconductor device comprising:
- an insulating layer;
- a first electrode that is embedded in the insulating layer and serves as one of source and drain electrodes;
- a semiconductor layer having an island shape over and in contact with the insulating layer and the first electrode;
- a second electrode that covers at least a part of an outer edge of the semiconductor layer and serves as the other of the source and drain electrodes;
- a gate insulating layer covering the semiconductor layer and the second electrode;
- and
- a gate electrode over the gate insulating layer,
- wherein the gate electrode has a ring shape that surrounds an entire outer edge of the first electrode in a top view,
- wherein the second electrode is located outside an outer edge of the gate electrode to surround at least a part of the outer edge of the gate electrode in the top view.
A semiconductor device comprising:
- an insulating layer;
- a first electrode that is embedded in the insulating layer and serves as one of source and drain electrodes;
- a semiconductor layer having an island shape over and in contact with the insulating layer and the first electrode;
- a second electrode that is over the semiconductor layer and serves as the other of the source and drain electrodes;
- a gate insulating layer covering the semiconductor layer and the first and second electrodes;
- and
- a gate electrode over the gate insulating layer,
- wherein the gate electrode has a ring shape that surrounds an entire outer edge of the second electrode in a top view,
- wherein the first electrode is in contact with a bottom surface of at least a part of an end portion of the semiconductor layer, and
- wherein the first electrode is located outside an outer edge of the gate electrode to surround at least a part of the outer edge of the gate electrode in the top view.
Dependencies are inferred from the claim text.