US4151540A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High beta, high frequency transistor structure
Assignee: National Semiconductor Corp
•
Filing: 1977-12-08
•
Granted: 1979-04-24
•
Expires: 1997-12-08
Abstract
Abstract High beta, high frequency transistors require very narrow and high resistance base structures, thereby placing a low limit of collector-emitter voltages that may be used without encountering "punch-through" breakdown. This invention permits the use of normal collector-emitter voltages without danger of punch-through problems by injecting into the high resistance base material an impurity grid that serves both as an electrostatic shield to increase the voltage breakdown level, and as a means of reducing the apparent lateral base resistance, thereby further increasing the high frequency capability of the device without degrading the high beta characteristics.
Inventors
- 👤 Wendell B. Sander
- 👤 William H. Shepherd
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:23
CPC Classifications
H; H10; H10P; H10P30/00; H10P30/20; H10P30/21; H10D; H10D62/00; H10D62/10; H10D62/102; H10D62/103; H10D62/105; H10D62/17; H10D62/177; H10P30/202; H10P30/204
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
75 words
In a transistor having an emitter and a collector of a first conductivity type of semiconductor material separated by a high resistivity base structure of a second conductivity type of semiconductor material, the improvement comprising: an electrostatic shield formed by a heavily doped region of second conductivity type of semiconductor material in said high resistivity base structure in the region of the base-emitter junction for inhibiting punch-through breakdown between collector and emitter of said transistor.
Claim 2
Dependent Claim
75 words
In a transistor having an emitter and a collector of a first conductivity type of semiconductor material separated by a high resistivity base structure of a second conductivity type of semiconductor material, the improvement comprising: an electrostatic shield formed by a heavily doped region of second conductivity type of semiconductor material in said high resistivity base structure in the region of the base-emitter junction for inhibiting punch-through breakdown between collector and emitter of said transistor.
Claim 3
Dependent Claim
20 words
The transistor claimed in claim 1 wherein said shield is fabricated in a plane substantially parallel with said base-emitter junction.
Claim 4
Dependent Claim
23 words
The transistor claimed in claim 1 wherein said shield is a grid of implanted ions of a second conductivity type of semiconductor impurity.
Claim 5
Dependent Claim
44 words
The transistor claimed in claim 1 further including a gate electrode overlying and insulated from said base structure between said emitter and said collector and wherein said shield is formed as a cylinder on an axis parallel to the surface of said gate electrode.
Claim 6
Dependent Claim
22 words
The transistor claimed in claim 3 wherein said grid of implanted ions is in a plane substantially parallel with said base-emitter junction.
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) | 1982-04-23 | 1982-10-23 | 1983-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-23 | 1986-10-23 | 1987-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-23 | 1990-10-23 | 1991-04-24 | $7700.00 | Window Closed / Lapsed |