Isolation diffusion method for making reduced beta transistor or diodes
Abstract
Abstract A method for making reduced beta transistors within one of a plurality of isolated regions of a microcircuit structure. The beta reduction is accomplished by using standard isolation diffusion technology modified only to the extent of opening a hole in the isolation diffusion mask at the base location of each desired reduced beta transistor having a subcollector. The isolation impurity, being of the same conductivity type as the base diffusion and being of relatively high impurity concentration, reduces the emitter efficiency of each desired reduced beta transistor to an extent whereby the reduced beta transistor functions substantially as a self-isolated diode. Self-isolation of the diodes is achieved utilizing a minimum of microcircuit device surface area by elimination of separate isolating regions for the resulting diodes.
Inventors
- 👤 S Wiedmann
Bibliographic Details
Claims Analysis
Total Claims: 0References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1976-11-05 | 1977-05-07 | 1977-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-05 | 1981-05-07 | 1981-11-06 | $3760.00 | Window Closed / Lapsed |
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