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US4956307A
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Thin oxide sidewall insulators for silicon-over-insulator transistors
Assignee: Texas Instruments Inc
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Filing: 1988-11-10
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Granted: 1990-09-11
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Expires: 2008-11-10
Abstract
Abstract A silicon-over-insulator transistor is provided having a semiconductor mesa (40) overlying a buried oxide (42). Insulating regions (50) are formed at the sides of the semiconductor mesa (40). An oxidizable layer (56) is formed over the mesa's insulating region (46). This oxidizable layer (56) is then anisotropically etched, resulting in oxidizable sidewalls (60). An optional foot (70) may be formed at the bottom edge of the oxidizable sidewalls (76). These oxidizable sidewalls (76) are then oxidized, resulting in a pure oxide sidewall (64). The gate (66) is then formed over the pure oxide sidewalls (64) and a gate oxide (62).
Inventors
- 👤 Gordon P. Pollack
- 👤 Mishel Matloubian
- 👤 Ravishankar Sundaresan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:44
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/031; H10D30/0321; H10D30/0323; H10D30/60; H10D30/67; H10D30/6729; H10D30/6737; H10D30/6739; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6306; H10P14/6308; Y; Y10; Y10S; Y10S257/00; Y10S257/906; Y10S438/00; Y10S438/911; Y10S438/953
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
49 words
a method of forming a radiation hard transistor comprising: forming a mesa from semiconductor material; forming an insulated region adjacent to said mesa; forming a conforming oxidizable layer on the sides of said insulator region; anisotropically etching said oxidizable layer; and oxidizing said oxidizable layer to create oxide sidewalls.
Claim 2
Independent Claim
49 words
a method of forming a radiation hard transistor comprising: forming a mesa from semiconductor material; forming an insulated region adjacent to said mesa; forming a conforming oxidizable layer on the sides of said insulator region; anisotropically etching said oxidizable layer; and oxidizing said oxidizable layer to create oxide sidewalls.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein said step of forming an insulator region comprises the step of forming an oxide encompassing said mesa.
Claim 4
Dependent Claim
19 words
the method of claim 1 wherein said step of forming an oxidizable layer comprises forming an amorphous silicon layer.
Claim 5
Dependent Claim
24 words
the method of claim 3 wherein said step of forming an amorphous silicon layer comprises the step of forming a doped amorphous silicon layer.
Claim 6
Dependent Claim
18 words
the method of claim 1 wherein said step of forming an oxidizable layer comprises forming a polysilicon layer.
Claim 7
Dependent Claim
22 words
The method of claim 5 wherein said step of forming a polysilicon layer comprises the step of forming a doped polysilicon layer.
Claim 8
Dependent Claim
25 words
the method of claim 1 wherein said step of forming said oxide sidewalls further comprises forming a foot at the bottom edge of said sidewalls.
Claim 9
Dependent Claim
56 words
the method of claim 7 wherein said step of forming said foot and said step of anisotropically etching said oxidable layer comprises: forming TEOS layer over said oxidizable layer; anisotropically etching said TEOS layer and said oxidable layer; and removing said TEOS layer in order to define said foot at the bottom edge of said sidewall.
Claim 10
Independent Claim
60 words
a method of forming a transistor comprising: forming a mesa from semiconductor material; forming an insulator region encompassing said mesa; forming a conforming oxidable layer on said insulated region; forming a conforming spacer layer on said oxidable layer; anisotropically etching said spacer layer and said oxidable layer; removing said spacer layer; and oxidizing said oxidizable layer to create oxide walls.
Claim 11
Independent Claim
60 words
a method of forming a transistor comprising: forming a mesa from semiconductor material; forming an insulator region encompassing said mesa; forming a conforming oxidable layer on said insulated region; forming a conforming spacer layer on said oxidable layer; anisotropically etching said spacer layer and said oxidable layer; removing said spacer layer; and oxidizing said oxidizable layer to create oxide walls.
Claim 12
Dependent Claim
19 words
The method of claim 9 wherein said step of forming an oxidable layer comprises forming an amorphous silicon layer.
Claim 13
Dependent Claim
20 words
the method of claim 10 wherein said step of forming an amorphous silicon layer comprises forming doped amorphous silicon layer.
Claim 14
Dependent Claim
18 words
The method of claim 9 wherein said step of forming an oxidable layer comprises forming a polysilicon layer.
Claim 15
Dependent Claim
19 words
The method of claim 12 wherein said step of forming a polysilicon layer comprises forming a doped polysilicon layer.
Claim 16
Dependent Claim
15 words
The method of claim 9 and further comprising forming a gate over said insulator region.
Claim 17
Dependent Claim
12 words
The method of claim 9 wherein said spacer layer comprises silicon dioxide.
Claim 18
Dependent Claim
13 words
The method of claim 15 wherein said spacer layer comprises TEOS silicon dioxide.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-09-10 | 1994-03-12 | 1994-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-10 | 1998-03-12 | 1998-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-10 | 2002-03-12 | 2002-09-11 | $7700.00 | Window Closed / Lapsed |