Patent US4504330A successfully refreshed from Google Patents.
US4504330A
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US
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Optimum reduced pressure epitaxial growth process to prevent autodoping
Assignee: International Business Machines Corp
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Filing: 1983-10-19
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Granted: 1985-03-12
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Expires: 2003-10-19
Abstract
Abstract A reduced pressure epitaxial deposition method is disclosed to maximize performance and leakage limited yield of devices formed in the epitaxial layer. The method includes specified prebake and deposition conditions designed to minimize arsenic (buried subcollector) and boron (buried isolation) autodoping effects when pressures below one atmosphere are selected in accordance with the subcollector-to-isolation area ratio.
Inventors
- 👤 Arun K. Gaind
- 👤 Subhash B. Kulkarni
- 👤 Michael R. Poponiak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:22
CPC Classifications
H; H10; H10W; H10W15/00; H10P; H10P14/00; H10P14/20; H10P14/24; H10P14/29; H10P14/2901; H10P14/2902; H10P14/2905; H10P14/34; H10P14/3402; H10P14/3404; H10P14/3411; H10P32/00; H10P32/10; H10P32/15; H10W15/01; Y; Y10; Y10S; Y10S438/00; Y10S438/914; Y10S438/916
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
138 words
A reduced pressure epitaxial deposition process comprising: providing a silicon substrate having an arsenic subcollector area and a boron isolation area bearing a predetermined ratio relative to each other, baking said substrate at a temperature in the range from about 1125° C. to about 1150° C. for a time in the range from about 10 to about 20 minutes at a pressure below one atmosphere and within the hatched area shown in the plot of FIG. 3 as a function of said ratio, and depositing epitaxial silicon using a silicon tetrachloride process at a temperature in said range, using a growth rate in the range from about 0.05 to about 0.5 micrometers per minute, and a pressure below one atmosphere and within the hatched area shown in said plot of FIG. 3 as a function of said ratio.
Claim 2
Dependent Claim
138 words
A reduced pressure epitaxial deposition process comprising: providing a silicon substrate having an arsenic subcollector area and a boron isolation area bearing a predetermined ratio relative to each other, baking said substrate at a temperature in the range from about 1125° C. to about 1150° C. for a time in the range from about 10 to about 20 minutes at a pressure below one atmosphere and within the hatched area shown in the plot of FIG. 3 as a function of said ratio, and depositing epitaxial silicon using a silicon tetrachloride process at a temperature in said range, using a growth rate in the range from about 0.05 to about 0.5 micrometers per minute, and a pressure below one atmosphere and within the hatched area shown in said plot of FIG. 3 as a function of said ratio.
Claim 3
Dependent Claim
18 words
The method defined in claim 1 and further comprising the fabrication of bipolar transistors in said epitaxial silicon.
Claim 4
Dependent Claim
19 words
The method defined in claim 1 wherein said boron isolation area is zero and said pressure is 80 Torr.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-03-11 | 1988-09-10 | 1989-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-11 | 1992-09-10 | 1993-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-11 | 1996-09-10 | 1997-03-12 | $7700.00 | Window Closed / Lapsed |