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US4897366A
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US
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Method of making silicon-on-insulator islands
Assignee: Intersil Corp
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Filing: 1989-01-18
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Granted: 1990-01-30
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Expires: 2009-01-18
Abstract
Abstract A silicon-on-insulator (SOI) semiconductor device is made by forming a layer of single crystalline silicon on the surface of an insulating substrate. Portions of the silicon layer are removed, such as by etching, to form islands of the single crystalline silicon on the substrate with the islands having sharp corners between their side walls and their top surface. The silicon islands are then exposed to vapors of hydrogen chloride which etch the corners and form the islands with smooth, rounded corners between the side walls and the top surface.
Inventors
- 👤 Ronald K. Smeltzer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:19
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/24; H10P50/242; H10D; H10D86/00; H10D86/01; H10D86/03; Y; Y10; Y10S; Y10S148/00; Y10S148/15
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
65 words
In a method of forming an island of single crystalline silicon on an insulating substrate wherein the island is formed on the substrate with sharp corners between the side walls and the top surface of the island, the improvement comprising: exposing the island to vapors of hydrogen chloride at a temperature of between 930° C. and 970° C. to round the corners of the islands.
Claim 2
Dependent Claim
65 words
In a method of forming an island of single crystalline silicon on an insulating substrate wherein the island is formed on the substrate with sharp corners between the side walls and the top surface of the island, the improvement comprising: exposing the island to vapors of hydrogen chloride at a temperature of between 930° C. and 970° C. to round the corners of the islands.
Claim 3
Dependent Claim
21 words
A method in accordance with claim 1 in which the hydrogen chloride vapors are at a temperature of about 950° C.
Claim 4
Dependent Claim
25 words
A method in accordance with claim 2 in which the islands are exposed to the hydrogen chloride for a period of 10 to 30 minutes.
Claim 5
Dependent Claim
24 words
A method in accordance with claim 3 in which the islands are exposed to the hydrogen chloride for a period of about 10 minutes.
Claim 6
Dependent Claim
21 words
A method in accordance with claim 3 in which the hydrogen chloride vapors are at a concentration of 0.25% in hydrogen.
Claim 7
Independent Claim
112 words
A method of making a silicon-on-insulator semiconductor device comprising the steps of: forming a layer of single crystalline silicon on the surface of an insulating substrate; covering portions of the silicon layer with a layer of a masking material; removing the exposed portions of the silicon layer to form at least one island of the single crystalline silicon having side walls and a top surface with sharp corners between the side walls and the top surface; and exposing the silicon island to vapors of hydrogen chloride at a temperature of between 930° C. to 970° C. to form the island with smooth rounded corners between the side walls and the top surface.
Claim 8
Independent Claim
112 words
A method of making a silicon-on-insulator semiconductor device comprising the steps of: forming a layer of single crystalline silicon on the surface of an insulating substrate; covering portions of the silicon layer with a layer of a masking material; removing the exposed portions of the silicon layer to form at least one island of the single crystalline silicon having side walls and a top surface with sharp corners between the side walls and the top surface; and exposing the silicon island to vapors of hydrogen chloride at a temperature of between 930° C. to 970° C. to form the island with smooth rounded corners between the side walls and the top surface.
Claim 9
Dependent Claim
21 words
A method in accordance with claim 6 in which the hydrogen chloride vapors are at a temperature of about 950° C.
Claim 10
Dependent Claim
26 words
A method in accordance with claim 7 in which the island is exposed to the hydrogen chloride vapors for a period of 10 to 30 minutes.
Claim 11
Dependent Claim
25 words
A method in accordance with claim 8 in which the island is exposed to the hydrogen chloride vapors for a period of about 10 minutes.
Claim 12
Dependent Claim
21 words
A method in accordance with claim 7 in which the hydrogen chloride vapors are at a concentration of 0.25% in hydrogen.
Claim 13
Dependent Claim
23 words
A method in accordance with claim 6 in which the masking material is removed before exposing the island to the hydrogen chloride vapors.
Claim 14
Dependent Claim
22 words
A method in accordance with claim 6 in which the uncovered portions of the silicon layer are removed by an etching technique.
References Cited (Backward Citations)
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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) | 1993-01-29 | 1993-07-31 | 1994-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-29 | 1997-07-31 | 1998-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-29 | 2001-07-31 | 2002-01-30 | $7700.00 | Window Closed / Lapsed |