US4644383A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Subcollector for oxide and junction isolated IC's
Assignee: Intersil Corp
•
Filing: 1985-04-08
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Granted: 1987-02-17
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Expires: 2005-04-08
Abstract
Abstract A vertical bipolar transistor having a subcollector region of two different thicknesses is provided to increase packing density. The thicker portion lies beneath the area between the emitter and the collector contact. A single additional masking step is needed to provide the dual thickness subcollector region.
Inventors
- 👤 Osman E. Akcasu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:52
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/13; H10D62/137; H10D10/00; H10D10/40; H10D10/421; Y; Y10; Y10S; Y10S148/00; Y10S148/037; Y10S148/145; Y10S257/00; Y10S257/913
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
185 words
A bipolar vertical transistor comprising: a substrate of a first conductivity type; a collector region of a second conductivity type on said substrate and having a buried junction with said substrate; lateral isolation extending from a surface of said collector region to said substrate; a base region of said first conductivity type in a surface of said collector region; an emitter region of said second conductivity type in a surface of said base region; a subcollector region of said second conductivity type having a greater impurity concentration than said collector region at said junction between said collector region and said substrate; a collector contact region of said second conductivity type extending from said surface to said subcollector region; and said subcollector region having a thick portion extending laterally between the projection of said emitter region onto said junction and said collector contact region and extending vertical into said substrate a first depth and having a thin portion extending lateral from said thick portion toward but spaced from said lateral isolation and extending vertically into said substrate a second depth substantially less than said first depth.
Claim 2
Dependent Claim
185 words
A bipolar vertical transistor comprising: a substrate of a first conductivity type; a collector region of a second conductivity type on said substrate and having a buried junction with said substrate; lateral isolation extending from a surface of said collector region to said substrate; a base region of said first conductivity type in a surface of said collector region; an emitter region of said second conductivity type in a surface of said base region; a subcollector region of said second conductivity type having a greater impurity concentration than said collector region at said junction between said collector region and said substrate; a collector contact region of said second conductivity type extending from said surface to said subcollector region; and said subcollector region having a thick portion extending laterally between the projection of said emitter region onto said junction and said collector contact region and extending vertical into said substrate a first depth and having a thin portion extending lateral from said thick portion toward but spaced from said lateral isolation and extending vertically into said substrate a second depth substantially less than said first depth.
Claim 3
Dependent Claim
32 words
A bipolar vertical transistor according to claim 1 wherein said lateral isolation extends into said substrate a third depth and said second depth is at least as deep as said third depth.
Claim 4
Dependent Claim
37 words
A bipolar vertical transistor according to claim 2 wherein said lateral isolation includes a doped region of said first conductivity type in said substrate and having an impurity concentration greater tnan the impurity concentration of said substrate.
Claim 5
Dependent Claim
25 words
A bipolar vertical transistor according to claim 3 wherein said lateral isolation includes a dielectric region extending from said surface to said doped isolation region.
Claim 6
Dependent Claim
20 words
A bipolar vertical transistor according to claim 3 wherein said doped isolation region extends from said substrate to said surface.
Claim 7
Dependent Claim
19 words
A bipolar vertical transistor according to claim 1 wherein said collector region is an epitaxial layer on said substrate.
Claim 8
Dependent Claim
18 words
A bipolar vertical transistor according to claim 1 wherein said subcollector region is spaced from said base region.
Claim 9
Dependent Claim
48 words
A bipolar vertical transistor according to claim 1 wherein said collector region has a thickness in the range of 1 to 1.8 microns, said first depth is in the range of 2 to 3.5 microns and said second depth is in the range of 1 to 1.5 microns.
Claim 10
Dependent Claim
19 words
A bipolar vertical transistor according to claim 1 wherein said second depth is less than half said first depth.
Claim 11
Dependent Claim
18 words
A bipolar vertical transistor according to claim 1 wherein said subcollector has a uniform resistance at said junction.
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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) | 1990-02-16 | 1990-08-18 | 1991-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-16 | 1994-08-18 | 1995-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-16 | 1998-08-18 | 1999-02-17 | $7700.00 | Window Closed / Lapsed |