US4047218A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor devices with improved turn-off characteristics
Assignee: Motorola Solutions Inc
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Filing: 1976-07-16
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Granted: 1977-09-06
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Expires: 1996-07-16
Abstract
Abstract Semiconductor devices, with especial reference to transistors with reduced turn-off times. This improvement includes a low-barrier height metal contact to one of the lightly-doped regions of the device as a replacement for the conventional heavily-doped region or high-low junction structure usually employed for the purpose of providing ohmic contact.
Inventors
- 👤 Lowell E. Clark
- 👤 Raymond M. Roop
- 👤 Charles E. Volk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:21
CPC Classifications
H; H10; H10D; H10D8/00; H10D62/00; H10D62/10; H10D62/13; H10D62/137; H10D64/00; H10D64/20; H10D64/23; H10D64/231; H10D64/60; H10D64/64; H10W; H10W72/00; H10W72/50; H10W72/531; H10W72/536
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
96 words
In a high voltage semiconductor device including a first region of first conductivity-type, a second semiconductor region of second conductivity-type having at least lightly-doped portion, said lightly-doped portion forming a p-n junction with said first region, and separate first and second metallic means for contacting respectively each of said first and second regions remote from their p-n junction, wherein the improvement comprises said second region having a net impurity doping density of said second type between 3 × 10 12 and 10 15 atoms per square centimeter between said p-n junction and said second metallic means.
Claim 2
Dependent Claim
96 words
In a high voltage semiconductor device including a first region of first conductivity-type, a second semiconductor region of second conductivity-type having at least lightly-doped portion, said lightly-doped portion forming a p-n junction with said first region, and separate first and second metallic means for contacting respectively each of said first and second regions remote from their p-n junction, wherein the improvement comprises said second region having a net impurity doping density of said second type between 3 × 10 12 and 10 15 atoms per square centimeter between said p-n junction and said second metallic means.
Claim 3
Dependent Claim
23 words
A semiconductor device as recited in claim 1 where said second metallic means and said second region have a low barrier height contact.
Claim 4
Dependent Claim
59 words
A semiconductor device as recited in claim 1, further having a third region of second conductivity type in p-n junction forming relation with said first region and third metallic means for contacting said third region, where said first region is the base, said second region is the collector, and said third region is the emitter of a bipolar transistor.
Claim 5
Dependent Claim
24 words
A semiconductor device as recited in claim 3, where the impurity doping density in said second region is highest adjacent said second metallic means.
Claim 6
Dependent Claim
33 words
A semiconductor device as recited in claim 4, where the high doping density in said second region adjacent said second metallic means has a thickness substantially less than a minority carrier diffusion length.
References Cited (Backward Citations)
US3930909A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-05 | 1981-03-07 | 1981-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-05 | 1985-03-07 | 1985-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-05 | 1989-03-07 | 1989-09-06 | $7700.00 | Window Closed / Lapsed |