Patent US4996581A successfully refreshed from Google Patents.
US4996581A
Expired / Lapsed
US
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Bipolar transistor
Assignee: Toshiba Corp
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Filing: 1989-02-02
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Granted: 1991-02-26
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Expires: 2009-02-02
Abstract
Abstract A bipolar transistor including an emitter region of a first conductivity type, having a predetermined width, an inner base region of a second conductivity type, formed below the emitter region and contacting the emitter region, thus forming a PN junction, an outer base region of the second conductivity type, having a high impurity concentration, set in ohmic contact with the edge of the inner base region and surrounding the inner base region, an inner collector region of the first conductivity type, formed below the inner base region and contacting the inner base region, thus forming a PN junction, and an outer collector region of the first conductivity type, set in ohmic contact with the inner collector region, contacting the lower surface of the outer base region, thus forming a PN junction, and surrounding the inner collector region. The transistor is characterized in the following respects. First, the inner collector region has a higher impurity concentration than the outer collector region. Second, the edge of the inner collector region is located right below, or inner than, the edge of the emitter region. Third, the upper surface of the inner collector region is higher and closer to the emitter region, than the upper surface of the outer collector region.
Inventors
- 👤 Toshihiko Hamasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:23
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/13; H10D62/137; H10D62/138
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
207 words
A bipolar transistor comprising: an emitter region of a first conductivity type, having a predetermined width; an inner base region of a second conductivity type, formed below said emitter region and contacting said emitter region, thus forming a PN junction; an outer base region of a second conductivity type, having a high impurity concentration, set in contact with the side face of said inner base region and surrounding said inner base region; an inner collector region of the first conductivity type, formed below said inner base region and contacting the bottom face of said inner base region, thus forming a PN junction; and an outer collector region of the first conductivity type, set in contact with the bottom face of said inner collector region, contacting the bottom face of said outer base region, thus forming a PN junction, and surrounding said inner collector region, wherein said inner collector region has a higher impurity concentration than said outer collector region; the side edge of said inner collector region is located right below, or inner than, the side edge of said emitter region; and the top face of said inner collector region is higher and closer to said emitter region, than the top face of said outer collector region.
Claim 2
Dependent Claim
207 words
A bipolar transistor comprising: an emitter region of a first conductivity type, having a predetermined width; an inner base region of a second conductivity type, formed below said emitter region and contacting said emitter region, thus forming a PN junction; an outer base region of a second conductivity type, having a high impurity concentration, set in contact with the side face of said inner base region and surrounding said inner base region; an inner collector region of the first conductivity type, formed below said inner base region and contacting the bottom face of said inner base region, thus forming a PN junction; and an outer collector region of the first conductivity type, set in contact with the bottom face of said inner collector region, contacting the bottom face of said outer base region, thus forming a PN junction, and surrounding said inner collector region, wherein said inner collector region has a higher impurity concentration than said outer collector region; the side edge of said inner collector region is located right below, or inner than, the side edge of said emitter region; and the top face of said inner collector region is higher and closer to said emitter region, than the top face of said outer collector region.
Claim 3
Dependent Claim
44 words
The bipolar transistor according to claim 1, further comprising a buried collector region of the first conductivity type, having a high impurity concentration, formed below said inner and outer collector region, and set in contact with the bottom face of said outer collector region.
Claim 4
Dependent Claim
212 words
A bipolar transistor comprising: an emitter region of a first conductivity type, having a predetermined width; an inner base region of a second conductivity type, formed below said emitter region and contacting said emitter region, thus forming a PN junction; an outer base region of a second conductivity type, having a high impurity concentration, set in contact with the side face of said inner base region and surrounding said inner base region; an inner collector region of the first conductivity type, formed below said inner base region and contacting the bottom face of said inner base region, thus forming a PN junction; and an outer collector region of the first conductivity type, formed below said outer base region and said inner collector region, set in contact with the bottom face of said inner collector region, contacting the bottom face of said outer base region, thus forming a PNB junction, wherein said inner collector region has a higher impurity concentration than said outer collector region; the side edge of said inner collector region is located right below, or inner than, the side edge of said emitter region; and the top face of said inner collector region is higher and closer to said emitter region, than the top face of said outer collector region.
Claim 5
Dependent Claim
212 words
A bipolar transistor comprising: an emitter region of a first conductivity type, having a predetermined width; an inner base region of a second conductivity type, formed below said emitter region and contacting said emitter region, thus forming a PN junction; an outer base region of a second conductivity type, having a high impurity concentration, set in contact with the side face of said inner base region and surrounding said inner base region; an inner collector region of the first conductivity type, formed below said inner base region and contacting the bottom face of said inner base region, thus forming a PN junction; and an outer collector region of the first conductivity type, formed below said outer base region and said inner collector region, set in contact with the bottom face of said inner collector region, contacting the bottom face of said outer base region, thus forming a PNB junction, wherein said inner collector region has a higher impurity concentration than said outer collector region; the side edge of said inner collector region is located right below, or inner than, the side edge of said emitter region; and the top face of said inner collector region is higher and closer to said emitter region, than the top face of said outer collector region.
Claim 6
Dependent Claim
42 words
The bipolar transistor according to claim 3, further comprising a buried collector region of the first conductivity type, having a high impurity concentration, formed below said outer collector region, and set in contact with the bottom face of said outer collector region.
Claim 7
Dependent Claim
26 words
The bipolar transistor according to claim 1, wherein the impurity concentrations of said inner and outer collector regions are lower than that of said emitter region.
Claim 8
Dependent Claim
26 words
The bipolar transistor according to claim 3, wherein the impurity concentrations of said inner and outer collector regions are lower than that of said emitter 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) | 1994-02-25 | 1994-08-27 | 1995-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-25 | 1998-08-27 | 1999-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-25 | 2002-08-27 | 2003-02-26 | $7700.00 | Window Closed / Lapsed |