US4849797A
Expired / Lapsed
US
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Thin film transistor
Assignee: TPO Hong Kong Holding Ltd
•
Filing: 1988-01-20
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Granted: 1989-07-18
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Expires: 2008-01-20
Abstract
Abstract In a thin film transistor which has an active layer formed between source and drain electrodes, a gate insulating film formed in contact with the active layer, and a gate electrode formed in contact with the gate insulating film, the photoconductivity of the active layer is reduced by forming the active layer of amorphous silicon carbide (a-Si 1-x C x ) whose carbon content x is greater than 0.1.
Inventors
- 👤 Yasuhiro Ukai
- 👤 Shigeo Aoki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:30
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/136; G02F1/1362; G02F1/1368; H; H10; H10D; H10D30/00; H10D30/40; H10D30/47; H10D30/471; H10D30/473; H10D30/60; H10D30/67; H10D30/674; H10D30/6741; H10D30/6748; H10D62/00; H10D62/40; H10D62/402; H10D62/80; H10D62/81; H10D62/815; H10D62/8161; H10D62/8162; H10D62/8163; H10D62/82; H10D62/822; H10D62/83; H10D64/00; H10D64/60; H10D64/602; H10F; H10F77/00; H10F77/10; H10F77/16; H10F77/162; H10F77/166; H10F77/1662; H10F77/1665; H10D62/834; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/548
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
77 words
A thin film transistor which has an active layer formed between source and drain electrodes, a gate insulating film formed in contact with the active layer, and a gate electrode formed in contact with the gate insulating film, the improvement wherein said active layer is formed of amorphous silicon carbide (a-Si 1-x C x ) and the carbon content x of said amorphous silicon carbide is greater than 0.1 to reduce the photoconductivity of said active layer.
Claim 2
Dependent Claim
77 words
A thin film transistor which has an active layer formed between source and drain electrodes, a gate insulating film formed in contact with the active layer, and a gate electrode formed in contact with the gate insulating film, the improvement wherein said active layer is formed of amorphous silicon carbide (a-Si 1-x C x ) and the carbon content x of said amorphous silicon carbide is greater than 0.1 to reduce the photoconductivity of said active layer.
Claim 3
Dependent Claim
25 words
The thin film transistor of claim 1, wherein the carbon content x of the amorphous silicon carbide in said active layer is less than 0.95.
Claim 4
Dependent Claim
24 words
The thin film transistor of claim 2, wherein the amorphous silicon carbide in said active layer is doped with an element of group III.
Claim 5
Dependent Claim
15 words
The thin film transistor of claim 3, wherein the group III element is boron (B).
Claim 6
Dependent Claim
24 words
The thin film transistor of claim 2, wherein the amorphous silicon carbide in said active layer is doped with an element of group V.
Claim 7
Dependent Claim
15 words
The thin film transistor of claim 5, wherein the group V element is phosphorus (P).
Claim 8
Dependent Claim
37 words
The thin film transistor of claim 1, wherein the gate insulating film is formed of amorphous silicon carbide the carbon content x of which is greater than that of the amorphous silicon carbide forming the active layer.
Claim 9
Dependent Claim
46 words
The thin film transistor of claim 7, wherein the carbon content of the amorphous silicon carbide forming the active layer is less than 0.2 and the carbon content x of the amorphous silicon forming the gate insulating film is in the range of 0.2 <x <0.95.
Claim 10
Dependent Claim
42 words
The thin film transistor of claim 8 wherein the carbon content x of the amorphous silicon carbide in said active layer is about 0.1 and the carbon content x of the amorphous silicon carbide in said gate insulating film is about 0.5.
Claim 11
Dependent Claim
21 words
The thin film transistor of claim 8, wherein the amorphous silicon carbide in said active layer is doped with boron (B).
Claim 12
Dependent Claim
21 words
The thin film transistor of claim 8, wherein the amorphous silicon carbide in said active layer is doped with phosphorus (P).
Claim 13
Dependent Claim
45 words
The thin film transistor of claim 1, wherein the active layer of said amorphous silicon carbide is formed by an alternate lamination of well layers made of hydrogenated amorphous silicon (A-Si:H) and barrier layers made of hydrogenated amorphous silicon carbide (a-Si 1-x C x :H).
Claim 14
Dependent Claim
27 words
The thin film transistor of claim 12, wherein the well layers are each about 25 Å thick and the barrier layers are each about 50 Å thick.
Claim 15
Dependent Claim
19 words
The thin film transistor of claim 13, wherein the cycle of lamination of the well barrier layers is 15.
Claim 16
Dependent Claim
32 words
The thin film transistor of claim 12, wherein the gate insulating film is formed of amorphous silicon carbide, the carbon content x of which is greater than that of the active layer.
Claim 17
Dependent Claim
54 words
The thin film transistor of claim 1 wherein said active layer of amorphous silicon carbide is comprised of alternate laminations of well layers made of hydrogenated amorphous silicon carbide whose carbon content x is smaller than 0.5 and barrier layers made of hydrogenated amorphous silicon carbide whose carbon content x is greater than 0.5.
Claim 18
Dependent Claim
27 words
The thin film transistor of claim 16, wherein the well layers are each about 25 Å thick and the barrier layers are each about 50 Å thick.
Claim 19
Dependent Claim
20 words
The thin film transistor of claim 17, wherein the cycle of lamination of the well and barrier layers is 15.
Claim 20
Dependent Claim
32 words
The thin film transistor of claim 16, wherein the gate insulating film is formed of amorphous silicon carbide, the carbon content x of which is greater than that of the active layer.
References Cited (Backward Citations)
US3600218A
Cited
US4642144A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-17 | 1993-01-16 | 1993-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-17 | 1997-01-16 | 1997-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-17 | 2001-01-16 | 2001-07-18 | $7700.00 | Window Closed / Lapsed |