US3290189A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of selective diffusion from impurity source
Assignee: Hitachi Ltd
•
Filing: 1963-08-20
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Granted: 1966-12-06
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Expires: 1983-08-20
Abstract
No abstract record available.
Inventors
- 👤 Migitaka Masatoshi
- 👤 Kodera Hiroshi
- 👤 Ueda Hiroshi
- 👤 Kimura Hirokazu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:23
CPC Classifications
H; H10; H10P; H10P32/00; H10P32/10; H10P32/14; H10P32/1408; H10P32/141; C; C23; C23C; C23C10/00; C23C10/04; C30; C30B; C30B29/00; C30B29/02; C30B29/06; C30B31/00; C30B31/02; H10P32/17; H10P32/171; H10P95/00; Y; Y10; Y10S; Y10S148/00; Y10S148/023; Y10S148/071; Y10S148/151
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
138 words
THE PROCESS FOR MAKING A P-TYPE SILICON SEMI-CONDUCTOR COMPRISING (I) COATING A SURFACE OF THE BASE OF A SILICON CRYSTAL WITH A SOLUTION OF ETHER, METABORIC ACID AND PHOSPHOROUS PENTOXIDE; (II) HEATING AN AREA OF SAID COATED SURFACE TO A TEMPERATURE OF ABOUT 1000*C. FOR A SUFFICIENT TIME TO CONVERT A PORTION OF THE SURFACE OF SAID CRYSTAL INTO AN N-TYPE CONDUCTIVITY ZONE WHEREIN THE PHOSPHORUS DONOR ELEMENT PREDOMINATES; AND (III) THEN HEATING A PORTION OF SAID CONVERTED SURFACE TO A TEMPEATURE OF ABOUT 1200*C. FOR A SUFFICIENT TIME TO CONVERT A PORTION OF SAID N-TYPE CONDUCTIVITY ZONE INTO A P-TYPE CONDUCTIVITY ZONE WHEREIN BORON ATOMS PREDOMINATE AS THE IMPURITY, AND CONCOMITANTLY CAUSING SAID PORTION OF SAID N-TYPE CONDUCTIVITY ZONE FORMALLY AT THE SURFACE TO DIFFUSE DEEPER INTO THE ORIGINAL CRYSTAL BENEATH THE SUBSEQUENTLY FORMED P-TYPE CONDUCTIVITY ZONE.
Claim 2
Dependent Claim
138 words
THE PROCESS FOR MAKING A P-TYPE SILICON SEMI-CONDUCTOR COMPRISING (I) COATING A SURFACE OF THE BASE OF A SILICON CRYSTAL WITH A SOLUTION OF ETHER, METABORIC ACID AND PHOSPHOROUS PENTOXIDE; (II) HEATING AN AREA OF SAID COATED SURFACE TO A TEMPERATURE OF ABOUT 1000*C. FOR A SUFFICIENT TIME TO CONVERT A PORTION OF THE SURFACE OF SAID CRYSTAL INTO AN N-TYPE CONDUCTIVITY ZONE WHEREIN THE PHOSPHORUS DONOR ELEMENT PREDOMINATES; AND (III) THEN HEATING A PORTION OF SAID CONVERTED SURFACE TO A TEMPEATURE OF ABOUT 1200*C. FOR A SUFFICIENT TIME TO CONVERT A PORTION OF SAID N-TYPE CONDUCTIVITY ZONE INTO A P-TYPE CONDUCTIVITY ZONE WHEREIN BORON ATOMS PREDOMINATE AS THE IMPURITY, AND CONCOMITANTLY CAUSING SAID PORTION OF SAID N-TYPE CONDUCTIVITY ZONE FORMALLY AT THE SURFACE TO DIFFUSE DEEPER INTO THE ORIGINAL CRYSTAL BENEATH THE SUBSEQUENTLY FORMED P-TYPE CONDUCTIVITY ZONE.
References Cited (Backward Citations)
US2793145A
Cited
US2725315A
Cited
US2816847A
Cited
US2845371A
Cited
US2968723A
Cited
US3067485A
Cited
US3145126A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-12-05 | 1970-06-06 | 1970-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-12-05 | 1974-06-06 | 1974-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-12-05 | 1978-06-06 | 1978-12-06 | $7700.00 | Window Closed / Lapsed |