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US 5,859,445 AGranted
Electro-optical device including thin film transistors having spoiling impurities added thereto
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorShunpei Yamazaki
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Abstract
An electro-optical device having a plurality of pixel electrodes, each with at least one thin film transistor. The channel region of the transistor is spoiled by an impurity such as oxygen, carbon, or nitrogen. The photosensitivity of the channel region is reduced by the spoiling impurity and therefore the transistor includes immunity to illumination incident thereupon, which would otherwise impair the normal operation of the transistor. The spoiling impurity is not introduced into transistors that are located such that they do not receive light rays.
Claims49
An electro-optical device comprising:
- a substrate having an insulating surface;
- a plurality of pixel electrode s arranged in a matrix over said substrate, each of said pixel electrodes provided with at least one inverted staggered type thin film transistor;
- and
- said thin film transistor comprising source and drain semiconductor regions, a channel semiconductor region between said source and drain semiconductor regions, a gate electrode adjacent to said channel region and a gate insulator interposed between said channel region and said gate electrode, wherein at least said channel region is intentionally doped with at least one of oxygen, nitrogen and carbon for reducing a photosensitivity thereof.
1 more element
An electro-optical device comprising:
- a substrate having an insulating surface;
- a plurality of pixel electrodes arranged in a matrix over said substrate, each of said pixel electrodes provided with at least one inverted staggered type thin film transistor;
- and
- said thin film transistor comprising source and drain semiconductor regions, a channel semiconductor region between said source and drain semiconductor regions, a gate electrode adjacent to said channel region and a gate insulator interposed between said channel region and said gate electrode, wherein said channel region is intentionally doped with an impurity selected from the group consisting of oxygen, nitrogen and carbon so that a concentration of said impurity in said channel region is higher than that of said impurity in said source and drain regions.
1 more element
An electro-optical device comprising:
- a substrate having an insulating surface;
- a plurality of pixel electrodes arranged in a matrix over said substrate, each of said pixel electrodes provided with at least one thin film transistor;
- and
- said thin film transistor comprising source and drain semiconductor regions, a channel semiconductor region between said source and drain semiconductor regions, a gate electrode adjacent to said channel region and a gate insulator interposed between said channel region and said gate electrode, wherein at least said channel region is intentionally doped with an impurity at a concentration higher than 1.times.10.sup.19 atoms/cm.sup.3, said impurity comprising carbon, oxygen and nitrogen.
1 more element
An electro-optical device comprising;
- a substrate having an insulating surface;
- a plurality of pixel electrodes arranged in a matrix over said substrate, each of said pixel electrodes provided with at least one thin film transistor;
- and
- said thin film transistor comprising source and drain semiconductor regions, a channel semiconductor region between said source and drain semiconductor regions, a gate electrode adjacent to said channel region and a gate insulator interposed between said channel region and said gate electrode, wherein said channel region is intentionally doped with an impurity at a concentration higher than 1.times.10.sup.19 atoms/cm.sup.3, said impurity comprising carbon, oxygen and nitrogen, and a concentration of said impurity in said source and drain regions does not exceed 1.times.10.sup.19 atoms/cm.sup.3.
1 more element
An electro-optical device comprising:
- a substrate having an insulating surface;
- a plurality of pixel electrodes arranged in a matrix over said substrate, each of said pixel electrodes provided with at least one thin film transistor;
- and
- said thin film transistor comprising source and drain semiconductor regions, a channel semiconductor region between said source and drain semiconductor regions, a gate electrode adjacent to said channel region and a gate insulator interposed between said channel region and said gate electrode, wherein at least said channel region is intentionally doped with an impurity at a concentration higher than 7.times.10.sup.19 atoms/cm.sup.3, said impurity comprising carbon, oxygen and nitrogen.
1 more element
An electro-optical device comprising:
- a substrate having an insulating surface;
- a plurality of pixel electrodes arranged in a matrix over said substrate, each of said pixel electrodes provided with at least one thin film transistor;
- and
- said thin film transistor comprising source and drain semiconductor regions, a channel semiconductor region between said source and drain semiconductor regions, a gate electrode adjacent to said channel region and a gate insulator interposed between said channel region and said gate electrode, wherein said channel region is intentionally doped with an impurity at a concentration higher than 7.times.10.sup.19 atoms/cm.sup.3, said impurity comprising carbon, oxygen and nitrogen, and a concentration of said impurity in said source and drain regions does not exceed 7.times.10.sup.19 atoms/cm.sup.3.
1 more element
An electro-optical device comprising:
- a substrate having an insulating surface;
- a plurality of pixel electrodes arranged in a matrix form over said substrate, each of said pixel electrodes provided with at least one thin film transistor;
- and
- said thin film transistor comprising source and drain semiconductor regions, a channel semiconductor region between said source and drain semiconductor regions, a gate electrode adjacent to said channel semiconductor region and a gate insulator interposed between said channel semiconductor region and said gate electrode,
- wherein said channel semiconductor region contains an impurity selected from the group consisting of oxygen, nitrogen and carbon at a higher concentration than said source and drain semiconductor regions contain said impurity.
2 more elements
An electro-optical device comprising:
- a substrate having an insulating surface;
- a plurality of pixel electrodes arranged in a matrix form over said substrate, each of said pixel electrodes provided with at least one thin film transistor;
- and
- said thin film transistor comprising source and drain semiconductor regions, a channel semiconductor region between said source and drain semiconductor regions, a gate electrode adjacent to said channel semiconductor region and a gate insulator interposed between said channel semiconductor region and said gate electrode,
- wherein said channel semiconductor region contains carbon, oxygen and nitrogen at a total concentration higher than 1.times.10.sup.19 atoms/cm.sup.3, and a total concentration of said carbon, oxygen and nitrogen in said source and drain semiconductor regions does not exceed 1.times.10.sup.19 atoms/cm.sup.3.
2 more elements
An electro-optical device comprising:
- a substrate having an insulating surface;
- a plurality of pixel electrodes arranged in a matrix form over said substrate, each of said pixel electrodes provided with at least one thin film transistor;
- and
- said thin film transistor comprising source and drain semiconductor regions, a channel semiconductor region between said source and drain semiconductor regions, a gate electrode adjacent to said channel semiconductor region and a gate insulator interposed between said channel semiconductor region and said gate electrode,
- wherein a concentration of carbon, oxygen or nitrogen in said channel semiconductor region is greater than that in said source and drain semiconductor regions, and a total concentration of said carbon, oxygen and nitrogen in said source and drain semiconductor regions does not exceed 1.times.10.sup.19 atoms/cm.sup.3.
2 more elements
An electro-optical device comprising:
- a substrate having an insulating surface;
- a plurality of pixel electrodes arranged in a matrix form over said substrate, each of said pixel electrodes provided with at least one thin film transistor;
- and
- said thin film transistor comprising source and drain semiconductor regions, a channel semiconductor region between said source and drain semiconductor regions, a gate electrode adjacent to said channel semiconductor region and a gate insulator interposed between said channel semiconductor region and said gate electrode,
- wherein a concentration of carbon, oxygen or nitrogen in said channel semiconductor region is greater than that in said source and drain semiconductor regions, and a total concentration of said carbon, oxygen and nitrogen in said channel semiconductor region is higher than 1.times.10.sup.19 atoms/cm.sup.3.
2 more elements
An electro-optical device comprising:
- a substrate having an insulating surface;
- a plurality of pixel electrodes arranged in a matrix form over said substrate, each of said pixel electrodes provided with at least one thin film transistor;
- and
- said thin film transistor comprising source and drain semiconductor regions, a channel semiconductor region between said source and drain semiconductor regions, a gate electrode adjacent to said channel semiconductor region and a gate insulator interposed between said channel semiconductor region and said gate electrode,
- wherein a concentration of carbon, oxygen or nitrogen in said channel semiconductor region is greater than 1.times.10.sup.20 atoms/cm.sup.3 and said concentration is greater than that in said source and drain semiconductor regions.
2 more elements
Dependencies are inferred from the claim text.