US4414557A
Expired / Lapsed
US
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Bipolar transistors
Assignee: NTT Inc
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Filing: 1981-03-03
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Granted: 1983-11-08
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Expires: 2001-03-03
Abstract
Abstract A base region and a collector region of a bipolar transistor are interconnected through a hetero junction and forbidden band gap of the collector region is larger than that of the base region. When the transistor is made of a silicon base material, the collector region is made of oxygen containing polycrystalline silicon or amorphous silicon, whereas when made of a GaAs base alloy, the collector region is made of a mixed crystal of GaAs-AlAs.
Inventors
- 👤 Yoshihito Amemiya
- 👤 Tsuneo Urisu
- 👤 Yoshihiko Mizushima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:26
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/13; H10D62/137; H10D10/00; H10D10/80; H10D10/821; H10D10/861; H10D12/00; H10D62/40
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
101 words
In a bipolar transistor of the type comprising an emitter region, a base region and a collector region, the improvement wherein said collector region has a larger forbidden band gap than that of said base region and is made of material having different conductivity type from that of said base region and further comprising a high resistivity semiconductor region interposed between said base region said collector region, said high resistivity semiconductor region having the same conductivity type as said collector region, a lower impurity concentration than said collector region and the same forbidden band gap as that of said base region.
Claim 2
Dependent Claim
101 words
In a bipolar transistor of the type comprising an emitter region, a base region and a collector region, the improvement wherein said collector region has a larger forbidden band gap than that of said base region and is made of material having different conductivity type from that of said base region and further comprising a high resistivity semiconductor region interposed between said base region said collector region, said high resistivity semiconductor region having the same conductivity type as said collector region, a lower impurity concentration than said collector region and the same forbidden band gap as that of said base region.
Claim 3
Dependent Claim
24 words
The bipolar transistor according to claim 1 wherein said emitter region, said base region and said collector region and layered in the order mentioned.
Claim 4
Dependent Claim
26 words
The bipolar transistor according to claim 1 wherein each of said emitter, base and collector regions are respectively provided with an emitter, base and collector electrode.
Claim 5
Dependent Claim
34 words
The bipolar transistor according to claim 3 which further comprises a collector reinforcing semiconductor layer interposed between said collector region and said collector electrode and having the same conductivity type as said collector region.
Claim 6
Dependent Claim
42 words
The bipolar transistor according to claim 1 wherein said emitter region and said base region are interconnected through a hereto junction and wherein said emitter region is made of material having a larger forbidden band gap than that of said base region.
Claim 7
Dependent Claim
23 words
The bipolar transistor according to claim 1 wherein said emitter and collector regions are made of polycrystalline silicon or amorphous silicon containing oxygen.
Claim 8
Dependent Claim
38 words
The bipolar transistor according to claim 6 wherein said collector region comprises polycrystalline silicon containing 2 to 50 atomic % of oxygen and a donor or acceptor impurity of a concentration higher than 5×10 19 cm -5 .
Claim 9
Dependent Claim
33 words
The bipolar transistor according to claim 6 wherein said collector region is made of amorphous silicon containing a donor or an acceptor impurity of a concentration higher than 5×10 19 cm -3 .
Claim 10
Dependent Claim
22 words
The bipolar transistor according to claim 1 wherein said base, emitter and collector regions are made of a mixed crystal of GaAs-AlAs.
Claim 11
Dependent Claim
27 words
The bipolar transistor according to claim 9 wherein said collector region is made of a mixed crystal of GaAs-AlAs containing 1×10 18 cm -3 of an impurity.
References Cited (Backward Citations)
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Cited
JPS50128697A
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US4062034A
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US4169269A
Cited
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US4254429A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-11-07 | 1987-05-09 | 1987-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-11-07 | 1991-05-09 | 1991-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-11-07 | 1995-05-09 | 1995-11-08 | $7700.00 | Window Closed / Lapsed |