SEMICONDUCTOR DEVICE, DISPLAY DEVICE, AND ELECTRONIC APPLIANCE
First Claim
1. A semiconductor device comprising:
- a gate electrode layer;
a gate insulating layer over the gate electrode layer;
an oxide semiconductor layer over the gate insulating layer;
an oxide insulating layer in contact with part of the oxide semiconductor layer; and
a source electrode layer and a drain electrode layer in contact with part of the oxide semiconductor layer,wherein in the oxide semiconductor layer, a region between the source electrode layer and the oxide insulating layer and a region between the drain electrode layer and the oxide insulating layer each have a thickness less than each of a region overlapping with the source electrode layer, a region overlapping with the oxide insulating layer, and a region overlapping with the drain electrode layer.
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Accused Products
Abstract
In a channel protected thin film transistor in which a channel formation region is formed using an oxide semiconductor, an oxide semiconductor layer which is dehydrated or dehydrogenated by a heat treatment is used as an active layer, a crystal region including nanocrystals is included in a superficial portion in the channel formation region, and the rest portion is amorphous or is formed of a mixture of amorphousness/non-crystals and microcrystals, where an amorphous region is dotted with microcrystals. By using an oxide semiconductor layer having such a structure, a change to an n-type caused by entry of moisture or elimination of oxygen to or from the superficial portion and generation of a parasitic channel can be prevented and a contact resistance with a source and drain electrodes can be reduced.
182 Citations
18 Claims
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1. A semiconductor device comprising:
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a gate electrode layer; a gate insulating layer over the gate electrode layer; an oxide semiconductor layer over the gate insulating layer; an oxide insulating layer in contact with part of the oxide semiconductor layer; and a source electrode layer and a drain electrode layer in contact with part of the oxide semiconductor layer, wherein in the oxide semiconductor layer, a region between the source electrode layer and the oxide insulating layer and a region between the drain electrode layer and the oxide insulating layer each have a thickness less than each of a region overlapping with the source electrode layer, a region overlapping with the oxide insulating layer, and a region overlapping with the drain electrode layer. - View Dependent Claims (2, 3, 15)
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4. A semiconductor device comprising:
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a gate electrode layer; a gate insulating layer over the gate electrode layer; an oxide semiconductor layer over the gate insulating layer; an oxide insulating layer in contact with part of the oxide semiconductor layer; and a source electrode layer and a drain electrode layer in contact with part of the oxide semiconductor layer, wherein in the oxide semiconductor layer, a region between the source electrode layer and the oxide insulating layer and a region between the drain electrode layer and the oxide insulating layer each have a thickness less than each of a region overlapping with the source electrode layer, a region overlapping with the oxide insulating layer, and a region overlapping with the drain electrode layer, and wherein a superficial portion of the oxide semiconductor layer which is in contact with the oxide insulating layer has a crystal region. - View Dependent Claims (5, 6, 7, 16)
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8. A display device comprising:
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a pixel portion and a driver circuit portion over a substrate, the pixel portion and the driver circuit portion each including a thin film transistor, wherein the thin film transistor comprises; a gate electrode layer; a gate insulating layer over the gate electrode layer; an oxide semiconductor layer over the gate insulating layer; an oxide insulating layer in contact with part of the oxide semiconductor layer; and a source electrode layer and a drain electrode layer in contact with part of the oxide semiconductor layer, wherein in the oxide semiconductor layer, a region between the source electrode layer and the oxide insulating layer and a region between the drain electrode layer and the oxide insulating layer each have a thickness less than each of a region overlapping with the source electrode layer, a region overlapping with the oxide insulating layer, and a region overlapping with the drain electrode layer. - View Dependent Claims (9, 10, 17)
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11. A display device comprising:
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a pixel portion and a driver circuit portion over a substrate, the pixel portion and the driver circuit portion each including a thin film transistor, wherein the thin film transistor comprises; a gate electrode layer; a gate insulating layer over the gate electrode layer; an oxide semiconductor layer over the gate insulating layer; an oxide insulating layer in contact with part of the oxide semiconductor layer; and a source electrode layer and a drain electrode layer in contact with part of the oxide semiconductor layer, wherein in the oxide semiconductor layer, a region between the source electrode layer and the oxide insulating layer and a region between the drain electrode layer and the oxide insulating layer each have a thickness less than each of a region overlapping with the source electrode layer, a region overlapping with the oxide insulating layer, and a region overlapping with the drain electrode layer, and wherein a superficial portion of the oxide semiconductor layer which is in contact with the oxide insulating layer has a crystal region. - View Dependent Claims (12, 13, 14, 18)
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Specification