US3895977A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of fabricating a bipolar transistor
Assignee: Harris Corp
•
Filing: 1973-12-20
•
Granted: 1975-07-22
•
Expires: 1993-12-20
Abstract
Abstract An integrated circuit and fabrication thereof having bipolar transistors of approximately identical peak current gain and different current capacities. The peak current gain is a function of a fixed area emitter and current capacity is a function of the number of fixed area emitters used to form the individual transistor.
Inventors
- 👤 Thomas J Sanders
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 02:24
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/13; H10D62/133; H10D62/135; H10D84/00; H10D84/60; H10D84/641; H10D84/642
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
110 words
A PROCESS FOR FABRICATING TRANSISTORS HAVING APPROXIMATELY IDENTICAL PEAK CURRENT GAIN, BUT DIFFERENT CURRENT CAPACITIES COMPRISING THE STEPS OF: FORMING BASE REGIONS OF FIRST CURRENT CAPACITY TRANSISTOR AND SECOND CURRENT CAPACITY TRANSISTOR BY DIFFUSION, FORMING AN EMITTER REGION OF SAID FIRST CURRENT CAPACITY TRANSISTOR OF A GIVEN EFFECTIVE AREA AND AN EMITTER REGION OF SAID SECOND CURRENT CAPACITY TRANSISTOR OF A LARGER EFFECTIVE AREA THAN SAID GIVEN AREA SO THAT BOTH OF SAID EMITTER REGIONS HAVE SUBSTANTIALLY IDENTICAL IMPURITY DISTRIBUTION BY IMPURITY DEPOSITION AND DIFFUSION THROUGH A MASK HAVING A PLURALITY OF IDENTICAL AREA APERTURES, AND FORMING COLLECTOR CONTACT REGIONS OF SAID FIRST AND SECOND CURRENT CAPACITY TRANSISTORS BY DIFFUSION.
Claim 2
Dependent Claim
110 words
A PROCESS FOR FABRICATING TRANSISTORS HAVING APPROXIMATELY IDENTICAL PEAK CURRENT GAIN, BUT DIFFERENT CURRENT CAPACITIES COMPRISING THE STEPS OF: FORMING BASE REGIONS OF FIRST CURRENT CAPACITY TRANSISTOR AND SECOND CURRENT CAPACITY TRANSISTOR BY DIFFUSION, FORMING AN EMITTER REGION OF SAID FIRST CURRENT CAPACITY TRANSISTOR OF A GIVEN EFFECTIVE AREA AND AN EMITTER REGION OF SAID SECOND CURRENT CAPACITY TRANSISTOR OF A LARGER EFFECTIVE AREA THAN SAID GIVEN AREA SO THAT BOTH OF SAID EMITTER REGIONS HAVE SUBSTANTIALLY IDENTICAL IMPURITY DISTRIBUTION BY IMPURITY DEPOSITION AND DIFFUSION THROUGH A MASK HAVING A PLURALITY OF IDENTICAL AREA APERTURES, AND FORMING COLLECTOR CONTACT REGIONS OF SAID FIRST AND SECOND CURRENT CAPACITY TRANSISTORS BY DIFFUSION.
Claim 3
Dependent Claim
36 words
A process as in claim 1 wherein said emitter region of said second current capacity transistor is formed as a plurality of discrete emitter areas by a plurality of said identical area apertures in said mask.
Claim 4
Dependent Claim
48 words
A process as in claim 1 wherein forming said emitter region of said second current capacity transistor includes diffusing through a mask with identical fixed area apertures spaced sufficiently close together to produce a continuous emitter with an impurity distribution approximately identical to said first current capacity transistor.
Claim 5
Dependent Claim
19 words
A process as in claim 1 wherein said apertures are squares having an area of less than 0.1 mil2.
References Cited (Backward Citations)
US3543102A
Cited
US3673012A
Cited
US3629017A
Cited
US3670219A
Cited
US3676229A
Cited
US3761787A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-21 | 1979-01-20 | 1979-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-21 | 1983-01-20 | 1983-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-21 | 1987-01-20 | 1987-07-22 | $7700.00 | Window Closed / Lapsed |