US5614731A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin-film transistor element having a structure promoting reduction of light-induced leakage current
Assignee: Toshiba Corp
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Filing: 1995-08-11
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Granted: 1997-03-25
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Expires: 2015-08-11
Abstract
Abstract A thin-film semiconductor element provided on a channel area with a channel protection layer, characterized by the fact that a source electrode layer and a drain electrode layer respectively have overlapping areas on the channel protection layer, the side walls of the source electrode layer and the drain electrode layer extend in the overlapping areas beyond the side wall of the channel protection layer in at least one direction of the width thereof, and the source electrode layer and the drain electrode layer possess points of overlap intersection with the semiconductor layer at the points of overlap intersection thereof with the channel protection layer. Owing to the construction described above, the leakage current generated by exposure to light can be decreased and the thin-film semiconductor element can be produced by a simple process of manufacture.
Inventors
- 👤 Shuichi Uchikoga
- 👤 Nobuki Ibaraki
- 👤 Kouji Suzuki
- 👤 Takuya Shimano
- 👤 Kaichi Fukuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:23
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/031; H10D30/0312; H10D30/0316; H10D30/0321; H10D30/60; H10D30/67; H10D30/6704; H10D30/6723; H10D30/6729
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
182 words
A thin-film semiconductor element comprising: a substrate; a gate electrode layer on said substrate; an insulating layer on said gate electrode layer; a channel area comprising a semiconductor layer over said gate electrode and on said insulating layer; a channel protection layer on said channel area; a source and drain electrode layer on said channel protection layer defining a channel length between the source electrode layer and the drain electrode layer and a channel width transverse to the channel length; and a contact layer between said channel protection layer and said source and drain electrode layer; said semiconductor layer, said channel protection layer, and said contact layer being coextensive in the direction of said channel width; and said source and drain electrode layer having a greater length in the direction of said channel width than said contact layer; wherein the source and drain electrode layer overlaps said contact layer, said channel protection layer, and said semiconductor layer in the direction of said channel width; and wherein said source and drain electrode layer directly contacts said insulating layer at the point of overlap.
Claim 2
Dependent Claim
182 words
A thin-film semiconductor element comprising: a substrate; a gate electrode layer on said substrate; an insulating layer on said gate electrode layer; a channel area comprising a semiconductor layer over said gate electrode and on said insulating layer; a channel protection layer on said channel area; a source and drain electrode layer on said channel protection layer defining a channel length between the source electrode layer and the drain electrode layer and a channel width transverse to the channel length; and a contact layer between said channel protection layer and said source and drain electrode layer; said semiconductor layer, said channel protection layer, and said contact layer being coextensive in the direction of said channel width; and said source and drain electrode layer having a greater length in the direction of said channel width than said contact layer; wherein the source and drain electrode layer overlaps said contact layer, said channel protection layer, and said semiconductor layer in the direction of said channel width; and wherein said source and drain electrode layer directly contacts said insulating layer at the point of overlap.
Claim 3
Dependent Claim
47 words
A thin-film transistor element according to claim 1, wherein the side walls of said source and drain electrode layer extend beyond both of the side walls of said channel protection layer, and said source and drain electrode layer overlaps said semiconductor layer and said channel protection layer.
Claim 4
Dependent Claim
41 words
A thin-film transistor element according to claim 2, which satisfies the relation W 1 >W 0 wherein W 1 stands for the width of said source and drain electrode layer and W 0 for the width of said channel protection layer.
Claim 5
Dependent Claim
48 words
A thin-film transistor element according to claim 1, wherein the side walls of said source and drain electrode layer extend beyond either of the side walls of said channel protection layer, and said source and drain electrode layer overlaps with said semiconductor layer and said channel protection layer.
Claim 6
Dependent Claim
52 words
A thin-film transistor element according to claim 1, wherein said semiconductor layer exclusively contacts said source and drain electrode layer and avoids contacting a contact layer between said source and drain electrode layer and said semiconductor layer, at points where said source and drain electrode layer overlaps and contacts said semiconductor layer.
Claim 7
Dependent Claim
15 words
A thin-film transistor element according to claim 1, wherein said semiconductor layer comprises amorphous silicon.
Claim 8
Dependent Claim
185 words
A thin-film transistor element comprising: a substrate; a source and drain electrode layer on said substrate defining a channel length between the source electrode layer and the drain electrode layer and a channel width transverse to the length; a channel protection layer on said source and drain electrode layer; a contact layer between said channel protection layer and said source and drain electrode layer; a channel area comprising a semiconductor layer over said source and drain electrode layer and on said channel protection layer; and a gate insulation layer on said channel area, said semiconductor layer, said channel protection layer, and said contact layer being coextensive in the direction of said channel width; and said source and drain electrode layer having a greater length in the direction of said channel width than said contact layer; wherein the source and drain electrode layer extends beyond said contact layer, said channel protection layer, and said semiconductor layer in the direction of said channel width; and wherein said source and drain electrode layer directly contacts said insulating layer at the point beyond the extend of said contact layer.
Claim 9
Dependent Claim
185 words
A thin-film transistor element comprising: a substrate; a source and drain electrode layer on said substrate defining a channel length between the source electrode layer and the drain electrode layer and a channel width transverse to the length; a channel protection layer on said source and drain electrode layer; a contact layer between said channel protection layer and said source and drain electrode layer; a channel area comprising a semiconductor layer over said source and drain electrode layer and on said channel protection layer; and a gate insulation layer on said channel area, said semiconductor layer, said channel protection layer, and said contact layer being coextensive in the direction of said channel width; and said source and drain electrode layer having a greater length in the direction of said channel width than said contact layer; wherein the source and drain electrode layer extends beyond said contact layer, said channel protection layer, and said semiconductor layer in the direction of said channel width; and wherein said source and drain electrode layer directly contacts said insulating layer at the point beyond the extend of said contact layer.
Claim 10
Dependent Claim
47 words
A thin-film transistor element according to claim 7, wherein the side walls of said source and drain electrode layer extend beyond both of the side walls of said channel protection layer, and said source and drain electrode layer overlaps said semiconductor layer and said channel protection layer.
Claim 11
Dependent Claim
41 words
A thin-film transistor element according to claim 8, which satisfies the relation W 1 >W 0 wherein W 1 stands for the width of said source and drain electrode layer and W 0 for the width of said channel protection layer.
Claim 12
Dependent Claim
48 words
A thin-film transistor element according to claim 7, wherein the side walls of said source and drain electrode layer extend beyond either of the side walls of said channel protection layer and said source and drain electrode layer overlaps with said semiconductor layer and said channel protection layer.
Claim 13
Dependent Claim
52 words
A thin-film transistor element according to claim 7, wherein said semiconductor layer exclusively contacts said source and drain electrode layer and avoids contacting said contact layer between said source and drain electrode layer and said semiconductor layer, at points where said source and drain electrode layer overlaps and contacts said semiconductor layer.
Claim 14
Dependent Claim
15 words
A thin-film transistor element according to claim 7, wherein said semiconductor layer comprises amorphous silicon.
Claim 15
Dependent Claim
46 words
A liquid crystal display device comprising: a thin-film transistor element array substrate; a counter substrate; and a liquid crystal composition interposed between said two substrates, said thin-film transistor element disposed on said thin-film transistor element array substrate being a thin-film transistor element according to claim 1.
Claim 16
Dependent Claim
41 words
An image sensor comprising: a photodiode array consisting of a plurality of photodiodes; a thin-film transistor element consisting of a plurality of thin-film transistor elements; and a multiplexer, said thin-film transistor element being a thin-film transistor element according to claim 1.
Claim 17
Dependent Claim
220 words
A thin-film transistor element comprising: a substrate; a gate electrode layer on said substrate; an insulating layer on said gate electrode layer; a channel area comprising a semiconductor layer over said gate electrode layer and on said insulating layer; a channel protection layer on said channel area; a source and drain electrode layer on said channel protection layer defining a channel length between the source electrode layer and the drain electrode layer and a channel width transverse to the channel length; and a contact layer between said channel protection layer and said source and drain electrode layer, said semiconductor layer, said channel protection layer, and said contact layer being coextensive in the direction of said channel width; and said source and drain electrode layer having a greater length in the direction of said channel width than said contact layer, wherein said semiconductor layer has three areas in the direction of said channel length: (a) a low resistance area where a photo-carrier is excited by irradiation of light; (b) high resistance areas where the thin-film transistor element is off state, the high resistance areas being on both side of said low resistance area; and (c) areas where the semiconductor layer contacts said contact layer, the areas being the outermost side of the semiconductor layer and adjacent to the high resistance areas.
Claim 18
Dependent Claim
220 words
A thin-film transistor element comprising: a substrate; a gate electrode layer on said substrate; an insulating layer on said gate electrode layer; a channel area comprising a semiconductor layer over said gate electrode layer and on said insulating layer; a channel protection layer on said channel area; a source and drain electrode layer on said channel protection layer defining a channel length between the source electrode layer and the drain electrode layer and a channel width transverse to the channel length; and a contact layer between said channel protection layer and said source and drain electrode layer, said semiconductor layer, said channel protection layer, and said contact layer being coextensive in the direction of said channel width; and said source and drain electrode layer having a greater length in the direction of said channel width than said contact layer, wherein said semiconductor layer has three areas in the direction of said channel length: (a) a low resistance area where a photo-carrier is excited by irradiation of light; (b) high resistance areas where the thin-film transistor element is off state, the high resistance areas being on both side of said low resistance area; and (c) areas where the semiconductor layer contacts said contact layer, the areas being the outermost side of the semiconductor layer and adjacent to the high resistance areas.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-03-24 | 2000-09-23 | 2001-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-03-24 | 2004-09-23 | 2005-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-03-24 | 2008-09-23 | 2009-03-25 | $7700.00 | Window Closed / Lapsed |