US5023197A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacturing process of mesa SOI MOS transistor
Assignee: Ministère des Postes Télégraphes et Téléphones
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Filing: 1990-08-15
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Granted: 1991-06-11
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Expires: 2010-08-15
Abstract
Abstract A method for manufacturing a MOS transistor formed in a silicon block on insulator with convex rounded up edges, initially consisting in etching the block in a thin layer of silicon on insulator (SOI). In this method etching of the block comprises the following steps: forming at the position where it is desired to obtain the block a mask layer portion (3) having a thickness slightly higher than that of the SOI; depositing a second silicon layer (11) having a predetermined thickness; and anisotropically etching silicon until said insulator is apparent outside the mask layer portion.
Inventors
- 👤 Michel Haond
- 👤 Jean Galvier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 01:05
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/031; H10D30/0321; H10D30/0323; H10D86/00; H10D86/01; H10P; H10P50/00; H10P50/71; Y; Y10; Y10S; Y10S148/00; Y10S148/051; Y10S148/161; Y10S438/00; Y10S438/978
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
100 words
A method for manufacturing a MOS transistor in a silicon on insulator block wherein said block exhibits convex rounded up edges, initially consisting in etching the block in a thin layer of single crystal silicon on insulator, wherein etching of the block comprises the following steps: forming at the position where it is desired to obtain the block a mask layer portion (3) having a thickness slightly larger than that of the thin silicon on insulator layer; depositing a second silicon layer (11) having a predetermined thickness; and anisotropically etching silicon until said insulator is apparent outside said mask portion.
Claim 2
Independent Claim
100 words
A method for manufacturing a MOS transistor in a silicon on insulator block wherein said block exhibits convex rounded up edges, initially consisting in etching the block in a thin layer of single crystal silicon on insulator, wherein etching of the block comprises the following steps: forming at the position where it is desired to obtain the block a mask layer portion (3) having a thickness slightly larger than that of the thin silicon on insulator layer; depositing a second silicon layer (11) having a predetermined thickness; and anisotropically etching silicon until said insulator is apparent outside said mask portion.
Claim 3
Dependent Claim
29 words
A method according to claim 1, wherein the insulator on which is formed said thin silicon layer is constituted by a silicon oxide layer formed on a silicon wafer.
Claim 4
Dependent Claim
18 words
A method according to claim 1, wherein said mask is constituted by a silicon oxide/silicon nitride/silicon oxide sandwich.
Claim 5
Dependent Claim
16 words
A method according to claim 1, wherein said mask is constituted by a silicon oxide/silicon sandwich.
Claim 6
Dependent Claim
30 words
A method according to claim 3, further comprising the step consisting in implanting a dopant in the silicon block while it is still masked, in order to overdop its edges.
Claim 7
Dependent Claim
17 words
A method according to claim 1, wherein the mask is constituted by a silicon oxide/silicon/silicon oxide sandwich.
Claim 8
Dependent Claim
23 words
A method according to claim 6, further comprising the step consisting in implanting a dopant after formation of said mask layer portion (3).
Claim 9
Dependent Claim
55 words
A method according to claim 5, wherein the anisotropic etching step according to claim 1 is subdivided into the following steps: etching the silicon until the upper layer of the mask is apparent; etching the upper silicon layer of the mask; and etching the silicon until said insulator is apparent outside the mask layer portion.
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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) | 1994-06-10 | 1994-12-10 | 1995-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-10 | 1998-12-10 | 1999-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-10 | 2002-12-10 | 2003-06-11 | $7700.00 | Window Closed / Lapsed |