US5017990A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Raised base bipolar transistor structure and its method of fabrication
Assignee: International Business Machines Corp
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Filing: 1989-12-01
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Granted: 1991-05-21
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Expires: 2009-12-01
Abstract
Abstract The invention relates to a bipolar transistor structure which includes a layer of semiconductor material having a single crystal raised base, a single crystal or polycrystalline emitter and adjacent polycrystalline regions which provide an electrical connection to the emitter. The invention also relates to the method of fabricating such a structure and includes the step of depositing a conformal layer of semiconductor material of one conductivity type over a region of opposite conductivity and over insulation such that single crystal and polycrystalline regions form over single crystal material and insulation, respectively. In a subsequent step, a layer of opposite conductivity type semiconductor material is deposited on the first layer forming single crystal or polycrystalline material over single crystal and polycrystalline material over polycrystalline. Then, in a final step, the structure is subjected to an out-diffusion step which simultaneously forms a single crystal emitter region of opposite conductivity type, a p-n junction in the one conductivity type single crystal region and regions of opposite conductivity type which act as an interconnection to the emitter region.
Inventors
- 👤 Tze-Chiang Chen
- 👤 Ching-Te Kent Chuang
- 👤 Guann-Pyng Li
- 👤 Tak Hung Ning
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:03
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/01; H10D10/051; H10D10/054; H10D10/40; H10D62/00; H10D62/10; H10D62/17; H10D62/177
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
195 words
A bipolar transistor comprising: a semiconductor substrate of one conductivity type, a first layer of semiconductor material of second conductivity type disposed on said substrate said layer containing an aperture which exposes a portion of said substrate, at least a layer of insulation covering at least a portion of said first layer of semiconductor material, a second layer of semiconductor material conformally disposed over said layer of insulation and in said aperture said second layer containing a polycrystalline region disposed over said layer of insulation and a single crystal semiconductor region disposed over said exposed portion of said substrate forming at least a single polycrystalline-single crystal interface between said single crystal and said polycrystalline regions, said second layer of semiconductor material being of said one conductivity type and having a region of said second conductivity type disposed therein over said exposed portion of said substrate forming a semiconductor junction in said single crystal semiconductor region said junction defining the base and emitter regions of said transistor, a portion of said junction being parallel with said at least a single interface and terminating on said insulation said polycrystalline region being electrically connected to said emitter region.
Claim 2
Dependent Claim
195 words
A bipolar transistor comprising: a semiconductor substrate of one conductivity type, a first layer of semiconductor material of second conductivity type disposed on said substrate said layer containing an aperture which exposes a portion of said substrate, at least a layer of insulation covering at least a portion of said first layer of semiconductor material, a second layer of semiconductor material conformally disposed over said layer of insulation and in said aperture said second layer containing a polycrystalline region disposed over said layer of insulation and a single crystal semiconductor region disposed over said exposed portion of said substrate forming at least a single polycrystalline-single crystal interface between said single crystal and said polycrystalline regions, said second layer of semiconductor material being of said one conductivity type and having a region of said second conductivity type disposed therein over said exposed portion of said substrate forming a semiconductor junction in said single crystal semiconductor region said junction defining the base and emitter regions of said transistor, a portion of said junction being parallel with said at least a single interface and terminating on said insulation said polycrystalline region being electrically connected to said emitter region.
Claim 3
Dependent Claim
18 words
A bipolar transistor according to claim 1 wherein said semiconductor substrate is made of single crystal semiconductor material.
Claim 4
Dependent Claim
17 words
A bipolar transistor according to claim 1 wherein said semiconductor substrate is made of single crystal silicon.
Claim 5
Dependent Claim
15 words
A bipolar transistor according to claim 1 wherein said one conductivity type is n-conductivity type.
Claim 6
Dependent Claim
15 words
A bipolar transistor according to claim 1 wherein said one conductivity type is p-conductivity type.
Claim 7
Dependent Claim
15 words
A bipolar transistor according to claim 1 wherein said first layer is polycrystalline semiconductor material.
Claim 8
Dependent Claim
14 words
A bipolar transistor according to claim 1 wherein said first layer is polycrystalline silicon.
Claim 9
Dependent Claim
29 words
A bipolar transistor according to claim 1 wherein said at least a layer of insulation is a layer of silicon dioxide disposed on all surfaces of said first layer.
Claim 10
Dependent Claim
52 words
A bipolar transistor according to claim 1 wherein said at least a layer of insulation is a composite layer of silicon nitride and silicon dioxide disposed on the upper surface and sidewall of said first layer except for an undercut portion of said composite layer which exposes a portion of said sidewall.
Claim 11
Dependent Claim
42 words
A bipolar transistor according to claim 1 wherein said polycrystalline region is of said one conductivity type and said single crystal region includes a region of said one conductivity type separated from a region of opposite conductivity type by said semiconductor junction.
Claim 12
Dependent Claim
23 words
A bipolar transistor according to claim 10 wherein said one conductivity type is n-conductivity type and said opposite conductivity type is p-conductivity type.
Claim 13
Dependent Claim
23 words
A bipolar transistor according to claim 10 wherein said one conductivity type is p-conductivity type and said opposite conductivity type is n-conductivity type.
Claim 14
Dependent Claim
34 words
A bipolar transistor according to claim 1 wherein said emitter region includes a single crystal portion conformal with said semiconductor junction electrically connected to said polycrystalline region at said at least a single interface.
Claim 15
Dependent Claim
50 words
A bipolar transistor according to claim 1 wherein said emitter region includes a single crystal portion conformal with said semiconductor junction said emitter region extending from said p-n junction to the surface of said second layer and being connected to said polycrystalline region at said at least a single interface.
Claim 16
Dependent Claim
20 words
A bipolar transistor according to claim 1 wherein said base region is disposed atop said substrate forming semiconductor junction therewith.
Claim 17
Dependent Claim
35 words
A bipolar transistor according to claim 1 further including a region of recessed oxide disposed in said substrate at least a portion of said recessed oxide being disposed under said first layer of semiconductor material.
Claim 18
Dependent Claim
23 words
A bipolar transistor according to claim 16 wherein at least a portion of said single crystal semiconductor region overlaps said recessed oxide region.
Claim 19
Dependent Claim
32 words
A bipolar transistor according to claim 1 further including a region of recessed oxide disposed in said substrate and at least a portion of said base region overlapping said recessed oxide region.
Claim 20
Dependent Claim
36 words
A bipolar transistor according to claim 1 further including at least a region of second conductivity disposed in said substrate said at least a region of second conductivity type being electrically connected to said base region.
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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) | 1994-05-20 | 1994-11-19 | 1995-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-05-20 | 1998-11-19 | 1999-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-05-20 | 2002-11-19 | 2003-05-21 | $7700.00 | Window Closed / Lapsed |