US5171697A
Expired / Lapsed
US
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Method of forming multiple layer collector structure for bipolar transistors
Assignee: Texas Instruments Inc
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Filing: 1991-06-28
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Granted: 1992-12-15
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Expires: 2011-06-28
Abstract
Abstract Generally, and in one form of the invention, a multiple layer collector structure is provided which comprises a relatively thin, highly doped layer 12 and a relatively thick, low doped or non-intentionally doped layer 14.
Inventors
- 👤 William U. Liu
- 👤 Darrell G. Hill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:52
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/01; H10D10/021; H10D10/80; H10D10/821; H10D62/00; H10D62/10; H10D62/13; H10D62/137; H10D62/80; H10D62/85; Y; Y10; Y10S; Y10S148/00; Y10S148/011; Y10S148/072
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
59 words
A method for making a multiple layer collector structure for bipolar transistors, comprising the steps of: forming a relatively thick, low doped or non-intentionally doped layer; and epitaxially depositing a relatively thin, highly doped layer on said low doped or non-intentionally doped layer, wherein said relatively thick layer is at least ten times thicker than said relatively thin layer.
Claim 2
Independent Claim
59 words
A method for making a multiple layer collector structure for bipolar transistors, comprising the steps of: forming a relatively thick, low doped or non-intentionally doped layer; and epitaxially depositing a relatively thin, highly doped layer on said low doped or non-intentionally doped layer, wherein said relatively thick layer is at least ten times thicker than said relatively thin layer.
Claim 3
Dependent Claim
42 words
The method of claim 1, further comprising the step of depositing said highly doped layer thin enough to prevent energy acquired by a majority of carriers traversing said layer from being greater than the energy required for impact ionization in said layer.
Claim 4
Dependent Claim
32 words
The method of claim 1, further comprising the step of doping said highly doped layer to be fully depleted at a majority of base-collector bias voltages between zero and BV ceo .
Claim 5
Dependent Claim
30 words
The method of claim 1, further comprising the step of causing said low doped or non-intentionally doped layer to have a dopant concentration of < 1×10 16 atoms/cm 3 .
Claim 6
Dependent Claim
27 words
The method for claim 1, further comprising the step of doping said highly doped layer to have a dopant concentration of > 1×10 17 atoms/cm 3 .
Claim 7
Dependent Claim
18 words
The method of claim 1, further comprising the step of forming said base and collector layers of GaAs.
Claim 8
Dependent Claim
21 words
The method of claim 1, further comprising the step of forming said bipolar transistor to be a heterojunction bipolar transistor (HBT).
Claim 9
Independent Claim
102 words
A method for making a bipolar transistor, comprising the steps of: forming a substrate; epitaxially depositing a subcollector layer on said substrate; epitaxially depositing a first collector layer on said subcollector layer, said first collector layer being relatively thick and low doped or non-intentionally doped; epitaxially depositing a second collector layer on said first collector layer, said second collector layer being relatively thin and highly doped, wherein said first collector layer is at least ten times thicker than said second collector layer; epitaxially depositing a base layer on said second collector layer; and epitaxially depositing an emitter layer on said base layer.
Claim 10
Independent Claim
102 words
A method for making a bipolar transistor, comprising the steps of: forming a substrate; epitaxially depositing a subcollector layer on said substrate; epitaxially depositing a first collector layer on said subcollector layer, said first collector layer being relatively thick and low doped or non-intentionally doped; epitaxially depositing a second collector layer on said first collector layer, said second collector layer being relatively thin and highly doped, wherein said first collector layer is at least ten times thicker than said second collector layer; epitaxially depositing a base layer on said second collector layer; and epitaxially depositing an emitter layer on said base layer.
Claim 11
Dependent Claim
44 words
The method of claim 8, further comprising the step of depositing said second collector layer thin enough to prevent energy acquired by a majority of carriers traversing said second collector layer from being greater than the energy required for impact ionization in said layer.
Claim 12
Dependent Claim
32 words
The method of claim 8, further comprising the step of doping said second collector layer to be fully depleted at a majority of base-collector bias voltages between zero and BV ceo .
Claim 13
Dependent Claim
27 words
The method of claim 8, further comprising the step of causing said first collector layer to have a dopant concentration of < 1×10 16 atoms/cm 3 .
Claim 14
Dependent Claim
27 words
The method for claim 8, further comprising the step of doping said second collector layer to have a dopant concentration of > 1×10 17 atoms/cm 3 .
Claim 15
Dependent Claim
18 words
The method of claim 8, further comprising the step of forming said base and collector layers of GaAs.
Claim 16
Dependent Claim
26 words
The method of claim 8, further comprising the step of forming said emitter layer of semiconductor material having a wider energy bandgap than said base layer.
References Cited (Backward Citations)
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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) | 1995-12-15 | 1996-06-15 | 1996-12-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-12-15 | 2000-06-15 | 2000-12-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-12-15 | 2004-06-15 | 2004-12-15 | $7700.00 | Window Closed / Lapsed |