US4199386A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of diffusing aluminum into monocrystalline silicon
Assignee: RCA Corp
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Filing: 1978-11-28
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Granted: 1980-04-22
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Expires: 1998-11-28
Abstract
Abstract Uniform aluminum diffusion into monocrystalline silicon is obtained by forming a polycrystalline silicon underlayer on the surface of a monocrystalline silicon body, depositing a layer of aluminum on the polycrystalline silicon underlayer by evaporation at a temperature of less than about 250° C., depositing a silicon overlayer over said aluminum layer at a temperature less than about 250° C. and raising the temperature of said structure to between 900° C. and 1300° C. to cause the aluminum to diffuse into said monocrystalline silicon.
Inventors
- 👤 Wojciech Rosnowski
- 👤 John M. S. Neilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:02
CPC Classifications
H; H10; H10P; H10P32/00; H10P32/10; H10P32/17; H10P32/171; H10P32/14; H10P32/1408; H10P32/1414; Y; Y10; Y10S; Y10S148/00; Y10S148/033; Y10S148/122
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
101 words
A method of diffusing aluminum into monocrystalline silicon comprising the steps of: first forming a polycrystalline silicon underlayer on a first surface of a body comprising said monocrystalline silicon; second forming a layer of aluminum metal on said first surface of said body while said monocrystalline silicon is at a temperature which is less than about 250° C.; third forming a silicon overlayer on said aluminum layer at a temperature which is less than about 250° C.; and raising the temperature of said body to between 900° C. and 1300° C. to cause the aluminum to diffuse into the monocrystalline silicon.
Claim 2
Independent Claim
101 words
A method of diffusing aluminum into monocrystalline silicon comprising the steps of: first forming a polycrystalline silicon underlayer on a first surface of a body comprising said monocrystalline silicon; second forming a layer of aluminum metal on said first surface of said body while said monocrystalline silicon is at a temperature which is less than about 250° C.; third forming a silicon overlayer on said aluminum layer at a temperature which is less than about 250° C.; and raising the temperature of said body to between 900° C. and 1300° C. to cause the aluminum to diffuse into the monocrystalline silicon.
Claim 3
Dependent Claim
24 words
The method recited in claim 1 wherein said third forming step comprises sputtering a layer of polycrystalline silicon over said layer of aluminum metal.
Claim 4
Dependent Claim
30 words
The method recited in claim 1 wherein said monocrystalline silicon is maintained at a temperature of 200° C. or less during said second forming step and said third forming step.
Claim 5
Dependent Claim
67 words
The method recited in claim 1 further comprising performing the following steps after said third forming step and prior to further heat treatment of the structure: forming a mask on said wafer, said mask having protective regions where it is desired to selectively diffuse aluminum and having non-protective regions elsewhere; removing the non-protected portions of said silicon overlayer; and removing the non-protected portions of said aluminum layer.
Claim 6
Dependent Claim
49 words
The method recited in claim 4 further comprising performing the following step after the step of removing the non-protected portions of said layer of aluminum metal: at least partially removing the now unprotected portions of said polycrystalline silicon underlayer in order to insure that no undesired aluminum remains thereon.
Claim 7
Dependent Claim
57 words
The method recited in claim 1 further comprising performing the following steps after said second forming step and prior to said third forming step: forming a mask on said wafer, said masking having protective regions where it is desired to selectively diffuse aluminum and having non-protective regions elsewhere; and removing the non-protected portions of said aluminum layer.
Claim 8
Dependent Claim
49 words
The method recited in claim 6 further comprising performing the following step after the step of removing the non-protected portions of said layer of aluminum metal: at least partially removing the now unprotected portions of said polycrystalline silicon underlayer in order to insure that no undesired aluminum remains thereon.
Claim 9
Independent Claim
80 words
A method of diffusing aluminum into monocrystalline silicon comprising the steps of: first forming a layer of aluminum metal on a first surface of a body comprising monocrystalline silicon; second forming a silicon overlayer on said first surface of said body while said monocrystalline silicon is at a temperature which is less than about 250° C.; and raising the temperature of said body to between 900° C. and 1300° C. to cause the aluminum to diffuse into the monocrystalline silicon.
Claim 10
Independent Claim
80 words
A method of diffusing aluminum into monocrystalline silicon comprising the steps of: first forming a layer of aluminum metal on a first surface of a body comprising monocrystalline silicon; second forming a silicon overlayer on said first surface of said body while said monocrystalline silicon is at a temperature which is less than about 250° C.; and raising the temperature of said body to between 900° C. and 1300° C. to cause the aluminum to diffuse into the monocrystalline silicon.
Claim 11
Dependent Claim
21 words
The method recited in claim 8 wherein said second forming step comprises sputtering a layer of polycrystalline silicon over said aluminum.
Claim 12
Dependent Claim
57 words
The method recited in claim 8 further comprising performing the following steps after said first forming step and prior to said second forming step: forming a mask on said wafer, said mask having protective regions where it is desired to selectively diffuse aluminum and having non-protective regions elsewhere; and removing the non-protected portions of said aluminum layer.
Claim 13
Dependent Claim
68 words
The method recited in claim 8 further comprising performing the following steps after said second forming step and prior to further heat treatment of the structure: forming a mask on said body, said mask having protective regions where it is desired to selectively diffuse aluminum and having non-protected regions elsewhere; removing the non-protected portions of said silicon overlayer; and removing the now unprotected portions of said aluminum layer.
References Cited (Backward Citations)
US2931743A
Cited
US3067071A
Cited
US3413157A
Cited
GB1252281A
Cited
US4106051A
Cited
US3909926A
Cited
US4029527A
Cited
US4040878A
Cited
US4099997A
Cited
US4029528A
Cited
US4050967A
Cited
US4154632A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-04-22 | 1983-10-22 | 1984-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-22 | 1987-10-22 | 1988-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-22 | 1991-10-22 | 1992-04-22 | $7700.00 | Window Closed / Lapsed |