US5541123A
Expired / Lapsed
US
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Method for forming a bipolar transistor having selected breakdown voltage
Assignee: Vishay Siliconix Inc
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Filing: 1995-06-05
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Granted: 1996-07-30
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Expires: 2015-06-05
Abstract
Abstract A process is disclosed (hereafter referred to as the "BiCDMOS Process") which simultaneously forms bipolar transistors, relatively high voltage CMOS transistors, relatively low voltage CMOS transistors, DMOS transistors, zener diodes, and thin-film resistors, or any desired combination of these, all on the same integrated circuit chip. The process uses a small number of masking steps, forms high performance transistor structures, and results in a high yield of functioning die. Isolation structures, bipolar transistor structures, CMOS transistor structures, DMOS transistor structures, zener diode structures, and thin-film resistor structures are also disclosed.
Inventors
- 👤 Richard K. Williams
- 👤 Hamza Yilmaz
- 👤 Michael E. Cornell
- 👤 Jun W. Chen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:37
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/64; H10D30/65; H10D10/00; H10D10/01; H10D10/051; H10D10/40; H10D10/421; H10D30/601; H10D30/603; H10D30/66; H10D30/663; H10D62/00; H10D62/10; H10D62/17; H10D62/177; H10D84/00; H10D84/01; H10D84/0107; H10D84/0109; H10D84/02; H10D84/03; H10D84/038; H10D84/40; H10D84/401; H10D84/403; H10D62/13; H10D62/149; H10D62/151; H10D62/156; H10D62/157; Y; Y10; Y10S; Y10S148/00; Y10S148/082; Y10S148/126; Y10S438/00; Y10S438/983
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
199 words
A method for forming a bipolar transistor to achieve a selected breakdown voltage comprising the steps of: forming a base region of a first conductivity type in a semiconductor material of a second conductivity type; forming a collector contact region of a second conductivity type in said semiconductor material of said second conductivity type; forming a base contact region of said first conductivity type in said base region, said base contact region being more highly doped than said base region, said base contact region being spaced from a closest edge of said base region so as to increase a distance between said base contact region and said collector contact region, said distance being sufficient to avoid breakdown between said base contact region and said collector contact region through said semiconductor material of said second conductivity type; and forming a first region of said second conductivity type, but more lightly doped than said collector contact region, between said collector contact region and said base region to increase a breakdown voltage between said base contact region and said collector contact region, wherein said collector contact region and said first region surround said base region at a surface of said semiconductor material.
Claim 2
Independent Claim
199 words
A method for forming a bipolar transistor to achieve a selected breakdown voltage comprising the steps of: forming a base region of a first conductivity type in a semiconductor material of a second conductivity type; forming a collector contact region of a second conductivity type in said semiconductor material of said second conductivity type; forming a base contact region of said first conductivity type in said base region, said base contact region being more highly doped than said base region, said base contact region being spaced from a closest edge of said base region so as to increase a distance between said base contact region and said collector contact region, said distance being sufficient to avoid breakdown between said base contact region and said collector contact region through said semiconductor material of said second conductivity type; and forming a first region of said second conductivity type, but more lightly doped than said collector contact region, between said collector contact region and said base region to increase a breakdown voltage between said base contact region and said collector contact region, wherein said collector contact region and said first region surround said base region at a surface of said semiconductor material.
Claim 3
Dependent Claim
15 words
The method of claim 1 wherein said breakdown voltage is greater than approximately 16 volts.
Claim 4
Dependent Claim
27 words
The method of claim 1 wherein a minimum distance between an edge of said base region and said base contact region is greater than approximately one micron.
Claim 5
Dependent Claim
21 words
The method of claim 1 wherein said first conductivity type is a P-type and said second conductivity type is an N-type.
Claim 6
Dependent Claim
21 words
The method of claim 1 wherein said first conductivity type is an N-type and said second conductivity type is a P-type.
Claim 7
Dependent Claim
39 words
The method of claim 1 further comprising the step of forming an emitter region of said second conductivity type within said base region, said base contact region completely surrounding said emitter region at a surface of said semiconductor material.
Claim 8
Independent Claim
197 words
A method for forming a bipolar transistor to achieve a selected breakdown voltage comprising the steps of: forming a base region of a first conductivity type in a semiconductor material of a second conductivity type: forming a collector contact region of a second conductivity type in said semiconductor material of said second conductivity type; forming a base contact region of said first conductivity type in said base region, said base contact region being more highly doped than said base region, said base contact region being spaced from a closest edge of said base region so as to increase a distance between said base contact region and said collector contact region, said distance being sufficient to avoid breakdown between said base contact region and said collector contact region through said semiconductor material of said second conductivity type; and forming a first region of said second conductivity type, but more lightly doped than said collector contact region, between said collector contact region and said base region to prevent field inversion between said base region and said collector contact region, wherein said collector contact region and said first region surround said base region at a surface of said semiconductor material.
Claim 9
Independent Claim
197 words
A method for forming a bipolar transistor to achieve a selected breakdown voltage comprising the steps of: forming a base region of a first conductivity type in a semiconductor material of a second conductivity type: forming a collector contact region of a second conductivity type in said semiconductor material of said second conductivity type; forming a base contact region of said first conductivity type in said base region, said base contact region being more highly doped than said base region, said base contact region being spaced from a closest edge of said base region so as to increase a distance between said base contact region and said collector contact region, said distance being sufficient to avoid breakdown between said base contact region and said collector contact region through said semiconductor material of said second conductivity type; and forming a first region of said second conductivity type, but more lightly doped than said collector contact region, between said collector contact region and said base region to prevent field inversion between said base region and said collector contact region, wherein said collector contact region and said first region surround said base region at a surface of said semiconductor material.
Claim 10
Dependent Claim
15 words
The method of claim 7 wherein said breakdown voltage is greater than approximately 16 volts.
Claim 11
Dependent Claim
27 words
The method of claim 7 wherein a minimum distance between an edge of said base region and said base contact region is greater than approximately one micron.
Claim 12
Dependent Claim
39 words
The method of claim 7 further comprising the step of forming an emitter region of said second conductivity type within said base region, said base contact region completely surrounding said emitter region at a surface of said semiconductor material.
Claim 13
Independent Claim
181 words
A method for forming a bipolar transistor to achieve a selected breakdown voltage comprising the steps of: forming a base region of a first conductivity type in a semiconductor material of a second conductivity type; forming a collector contact region of a second conductivity type in said semiconductor material of said second conductivity type; forming a base contact region of said first conductivity type in said base region, said base contact region being more highly doped than said base region, said base contact region being spaced from a closest edge of said base region so as to increase a distance between said base contact region and said collector contact region, said distance being sufficient to avoid breakdown between said base contact region and said collector contact region through said semiconductor material of said second conductivity type; and forming a drift region of said first conductivity type contacting said base region, but shallower than said base region, extending from said base region toward said collector contact region to increase a breakdown voltage between said base contact region and said collector contact region.
Claim 14
Independent Claim
181 words
A method for forming a bipolar transistor to achieve a selected breakdown voltage comprising the steps of: forming a base region of a first conductivity type in a semiconductor material of a second conductivity type; forming a collector contact region of a second conductivity type in said semiconductor material of said second conductivity type; forming a base contact region of said first conductivity type in said base region, said base contact region being more highly doped than said base region, said base contact region being spaced from a closest edge of said base region so as to increase a distance between said base contact region and said collector contact region, said distance being sufficient to avoid breakdown between said base contact region and said collector contact region through said semiconductor material of said second conductivity type; and forming a drift region of said first conductivity type contacting said base region, but shallower than said base region, extending from said base region toward said collector contact region to increase a breakdown voltage between said base contact region and said collector contact region.
Claim 15
Dependent Claim
52 words
The method of claim 11 further comprising the step of: forming a first region of said second conductivity type, but more lightly doped than said collector contact region, between said collector contact region and said base region to increase a breakdown voltage between said base contact region and said collector contact region.
Claim 16
Dependent Claim
15 words
The method of claim 11 wherein said breakdown voltage is greater than approximately 16 volts.
Claim 17
Dependent Claim
27 words
The method of claim 11 wherein a minimum distance between an edge of said drift region and said base contact region is greater than approximately one micron.
Claim 18
Dependent Claim
25 words
The method of claim 11 wherein said collector contact region and said drift region surround said base region at a surface of said semiconductor material.
Claim 19
Dependent Claim
39 words
The method of claim 11 further comprising the step of forming an emitter region of said second conductivity type within said base region, said base contact region completely surrounding said emitter region at a surface of said semiconductor material.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1999-07-30 | 2000-01-29 | 2000-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-30 | 2004-01-29 | 2004-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-30 | 2008-01-29 | 2008-07-30 | $7700.00 | Window Closed / Lapsed |