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US5834345A
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Method of fabricating field effect thin film transistor
Assignee: NEC Corp
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Filing: 1996-09-24
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Granted: 1998-11-10
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Expires: 2016-09-24
Abstract
Abstract A method of fabricating a field effect thin film transistor is provided, in which, after a first amorphous semiconductor layer having a predetermined thickness is deposited on a gate insulating film, the first amorphous semiconductor layer is transformed to a micro-crystal semiconductor layer by exposing it to hydrogen plasma produced by hydrogen discharge and, then, a second amorphous semiconductor layer is deposited on the micro-crystal semiconductor layer. According to this method, it is possible to fabricate a high performance and high quality field effect thin film transistor through a simplified step of forming the micro-crystal semiconductor which becomes a channel region thereof.
Inventors
- 👤 Kousaku Shimizu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 15:09
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/20; H10P14/38; H10P14/3802; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/031; H10D30/0312; H10D30/0316; H10D30/0321; H10D30/60; H10D30/67; H10D30/6729; H10D30/673; H10D30/6732; H10D30/674; H10D30/6741; H10D30/6743; H10D30/6745; H10D30/6746; H10P14/24; H10P14/29; H10P14/2901; H10P14/2922; H10P14/32; H10P14/3202; H10P14/3204; H10P14/3211; H10P14/3238; H10P14/3241; H10P14/3242; H10P14/3244; H10P14/3251; H10P14/3256; H10P14/34; H10P14/3402; H10P14/3404; H10P14/3411; H10P14/3438; H10P14/3441; H10P14/3442; H10P95/00; H10P95/94
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
165 words
A method of fabricating a field effect thin film transistor comprising the steps of: forming a gate insulating film on a gate electrode formed on an insulating substrate; depositing a first amorphous semiconductor layer on the gate insulating film; transforming the first amorphous semiconductor layer into a fine crystal semiconductor layer by exposing the first amorphous semiconductor layer to hydrogen plasma produced by hydrogen discharge; depositing a second amorphous semiconductor layer on the fine crystal semiconductor layer; depositing a third amorphous semiconductor layer containing high density impurity on the second amorphous semiconductor layer; transforming the third amorphous semiconductor layer into a micro-crystal semiconductor layer containing high density impurity by exposing the third amorphous semiconductor layer to hydrogen plasma produced by hydrogen discharge; and after forming a source electrode and a drain electrode which are electrically connected to the micro-crystal semiconductor layer containing high density impurity, etching the fine crystal semiconductor layer containing high density impurity using the source electrode and the drain electrode as masks.
Claim 2
Independent Claim
165 words
A method of fabricating a field effect thin film transistor comprising the steps of: forming a gate insulating film on a gate electrode formed on an insulating substrate; depositing a first amorphous semiconductor layer on the gate insulating film; transforming the first amorphous semiconductor layer into a fine crystal semiconductor layer by exposing the first amorphous semiconductor layer to hydrogen plasma produced by hydrogen discharge; depositing a second amorphous semiconductor layer on the fine crystal semiconductor layer; depositing a third amorphous semiconductor layer containing high density impurity on the second amorphous semiconductor layer; transforming the third amorphous semiconductor layer into a micro-crystal semiconductor layer containing high density impurity by exposing the third amorphous semiconductor layer to hydrogen plasma produced by hydrogen discharge; and after forming a source electrode and a drain electrode which are electrically connected to the micro-crystal semiconductor layer containing high density impurity, etching the fine crystal semiconductor layer containing high density impurity using the source electrode and the drain electrode as masks.
Claim 3
Dependent Claim
28 words
A method as claimed in claim 1, wherein the first and second amorphous semiconductor layers are of amorphous silicon and the micro-crystal semiconductor layer is of micro-crystal silicon.
Claim 4
Dependent Claim
48 words
A method as claimed in claim 2, wherein power density of the hydrogen discharge applied to the third amorphous silicon semiconductor layer exposed to hydrogen plasma is in a range from a value larger than 0.1 watt/cm 2 to a value not larger than 0.25 watts/cm 2 .
Claim 5
Dependent Claim
38 words
A method as claimed in claim 3, wherein the film thickness of the first amorphous silicon semiconductor layer is in a range from a value not smaller than 10 nm to a value not larger than 20 nm.
Claim 6
Dependent Claim
33 words
A method as claimed in claim 1, wherein the third amorphous semiconductor layer containing high density impurity is of amorphous silicon and the micro-crystal semiconductor layer containing high density impurity is micro-crystal silicon.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-11-09 | 2002-05-11 | 2002-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-11-09 | 2006-05-11 | 2006-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-11-09 | 2010-05-11 | 2010-11-10 | $7700.00 | Window Closed / Lapsed |