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US5323031A
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Bipolar transistor with a particular silicon germanium alloy structure
Assignee: Renesas Electronics Corp
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Filing: 1992-03-19
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Granted: 1994-06-21
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Expires: 2012-03-19
Abstract
Abstract To eliminate misfit dislocation occurring in a hetero-interface and to provide a bipolar transistor capable of a high speed operation, the bipolar transistor is configured such that the energy band gap is progressively narrowing from part of an emitter layer towards part of a collector layer through a base layer.
Inventors
- 👤 Kenichi Shoji
- 👤 Akira Fukami
- 👤 Takahiro Nagano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:54
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/01; H10D10/021; H10D10/80; H10D10/821; H10D10/891; H10D62/00; H10D62/80; H10D62/83; H10D62/832; H10D62/834
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
118 words
A bipolar transistor including a collector region of a first conductivity type, a base region of a second conductivity type, opposite to said first conductivity type, which forms a collector-base junction at an interface between said base region and said collector region, and an emitter region of said first conductivity type which forms a base-emitter junction at an interface between said emitter region and said base region, wherein portions of said emitter region and said base region in proximity of said base-emitter junction are formed of silicon-germanium alloy, and wherein the concentration of the germanium component of said silicon-germanium alloy in each of said portions is increasing along a direction from said emitter region to said base region.
Claim 2
Dependent Claim
118 words
A bipolar transistor including a collector region of a first conductivity type, a base region of a second conductivity type, opposite to said first conductivity type, which forms a collector-base junction at an interface between said base region and said collector region, and an emitter region of said first conductivity type which forms a base-emitter junction at an interface between said emitter region and said base region, wherein portions of said emitter region and said base region in proximity of said base-emitter junction are formed of silicon-germanium alloy, and wherein the concentration of the germanium component of said silicon-germanium alloy in each of said portions is increasing along a direction from said emitter region to said base region.
Claim 3
Dependent Claim
40 words
A bipolar transistor according to claim 1, wherein at least one element having a smaller lattice constant that silicon is contained in a part of the portion extending from an outer surface of said emitter region to the base-emitter junction.
Claim 4
Dependent Claim
26 words
A bipolar transistor according to claim 1, wherein said base and emitter regions are formed in an epitaxial region which is provided on a semiconductor substrate.
Claim 5
Dependent Claim
29 words
A bipolar transistor according to claim 1, wherein said collector, base and emitter regions are formed in a semiconductor body which includes as a base layer a semiconductor substrate.
Claim 6
Dependent Claim
40 words
A bipolar transistor according to claim 1, wherein the portions of said emitter and base regions, formed of silicon-germanium alloy, are extended inwardly as contiguously formed semiconductor portions from an outer surface of said emitter region toward the base-emitter junction.
Claim 7
Dependent Claim
15 words
A bipolar transistor according to claim 5, wherein said at least one element includes carbon.
Claim 8
Dependent Claim
50 words
A bipolar transistor according to claim 5, wherein at least one element having a smaller lattice constant than silicon is contained in a part within said emitter region, of the contiguously formed portions, which are extended inwardly from the outer surface of said emitter but not reaching the collector region.
Claim 9
Dependent Claim
33 words
A bipolar transistor according to claim 7, wherein said element having a smaller lattice constant than silicon is at least one element selected from the group essentially consisting of carbon, boron and nitrogen.
Claim 10
Dependent Claim
33 words
A bipolar transistor according to claim 8, wherein the contiguously formed portions cover an area, with respect to a plan view, smaller than an area of said emitter region at the surface thereof.
Claim 11
Dependent Claim
34 words
A bipolar transistor according to claim 8, wherein the contiguously formed portions cover an area, with respect to a plan view, substantially equal to an area of said emitter region at the surface thereof.
Claim 12
Dependent Claim
26 words
A bipolar transistor according to claim 7, wherein said base and emitter regions are formed in an epitaxial region which is provided on a semiconductor substrate.
Claim 13
Dependent Claim
41 words
A bipolar transistor according to the claim 1, wherein the portions of said emitter and base region, formed of silicon-germanium alloy, are extended inwardly as contiguously formed semiconductor portions from an outer surface of said emitter region toward said collector region.
Claim 14
Dependent Claim
33 words
A bipolar transistor according to claim 12, wherein said element having a smaller lattice constant than silicon is at least one element selected from the group essentially consisting of carbon, boron and nitrogen.
Claim 15
Dependent Claim
15 words
A bipolar transistor according to claim 12, wherein said at least one element includes carbon.
Claim 16
Dependent Claim
148 words
A bipolar transistor including a collector region of a first conductivity type, a base region of a second conductivity type, opposite to said first conductivity type, which forms a collector-base junction at an interface between said base region and said collector region, and an emitter region of said first conductivity type which forms a base-emitter junction at an interface between said emitter region and said base region, wherein each of said base region and said emitter region includes, with respect to a plan view, a relatively central portion which is formed of silicon-germanium alloy and a peripheral portion which surrounds said central portion and is formed of silicon, and wherein the concentration of the germanium component of said silicon-germanium alloy in the central portion of each of said base region and said emitter region is increasing along a direction extending from said emitter region to said base region.
Claim 17
Dependent Claim
148 words
A bipolar transistor including a collector region of a first conductivity type, a base region of a second conductivity type, opposite to said first conductivity type, which forms a collector-base junction at an interface between said base region and said collector region, and an emitter region of said first conductivity type which forms a base-emitter junction at an interface between said emitter region and said base region, wherein each of said base region and said emitter region includes, with respect to a plan view, a relatively central portion which is formed of silicon-germanium alloy and a peripheral portion which surrounds said central portion and is formed of silicon, and wherein the concentration of the germanium component of said silicon-germanium alloy in the central portion of each of said base region and said emitter region is increasing along a direction extending from said emitter region to said base region.
Claim 18
Dependent Claim
29 words
A bipolar transistor according to claim 15, wherein the central portions, formed of silicon-germanium alloy, of said base and emitter regions are contiguous portions extending to said collector region.
Claim 19
Dependent Claim
43 words
A bipolar transistor according to claim 16, wherein at least one element having a smaller lattice constant than silicon is contained in a part of the contiguously formed central portion extending from an outer surface of said emitter region to the base-emitter junction.
Claim 20
Dependent Claim
33 words
A bipolar transistor according to claim 17, wherein said element having a smaller lattice constant than silicon is at least one element selected from the group essentially consisting of carbon, boron and nitrogen.
Claim 21
Dependent Claim
15 words
A bipolar transistor according to claim 17, wherein said at least one element includes carbon.
Claim 22
Dependent Claim
18 words
A bipolar transistor according to claim 17, wherein said at least one element includes both boron and nitrogen.
Claim 23
Dependent Claim
41 words
A bipolar transistor according to claim 15, wherein at least one element having a smaller lattice constant than silicon is contained in a part of the central portion extending from an outer surface of said emitter region to the base-emitter junction.
Claim 24
Dependent Claim
33 words
A bipolar transistor according to claim 21, wherein said element having a smaller lattice constant than silicon is at least one element selected from the group essentially consisting of carbon, boron and nitrogen.
References Cited (Backward Citations)
US4885614A
Cited
JPH01231371A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-06-20 | 1997-12-20 | 1998-06-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-06-20 | 2001-12-20 | 2002-06-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-06-20 | 2005-12-20 | 2006-06-21 | $7700.00 | Window Closed / Lapsed |