US4249195A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mesa-type transistor and method of producing same
Assignee: US Philips Corp
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Filing: 1978-11-16
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Granted: 1981-02-03
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Expires: 1998-11-16
Abstract
Abstract The invention relates to a mesa transistor comprising a highly doped substrate, on which there is provided a lower doped collector region of the same conductivity type, a base zone of the opposite conductivity type provided on said collector region and an emitter zone provided in the base region with the mesa being formed by a recess in a flat upper face of the semiconductor plate which recess fully encloses the base zone and extends into the substrate. According to the invention the recess consists of a first portion extending over a part of the thickness of said collector region only, and a groove extending from the bottom of this first portion into the substrate. The wall and the bottom of this last-mentioned groove preferably everywhere adjoin a thin, highly doped semiconductor zone of the same conductivity type as the substrate.
Inventors
- 👤 Bernard Roger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:13
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/40; H10D10/441; H10D62/00; H10D62/10; H10D62/102; H10D62/103; H10D62/104; H10D62/13; H10D62/137
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
161 words
A semiconductor device being at least a bipolar transistor comprising a first semiconductor layer of a first conductivity type; a second semiconductor layer adjoining said first layer and being of a lower doping concentration of said first conductivity type, said first and second layers forming a collector zone; a third semiconductor layer situated on said second layer and being of a second conductivity type, said third layer forming at least a portion of a base zone; an emitter zone of said first conductivity type formed in a surface of said third layer away from said second layer; and a recess including a first portion extending from said surface of said third layer through said third layer and at least along a major surface of said second layer for a predetermine distance to form a mesa-like base zone, and a second portion being a groove extending from said first portion at said second layer through said second layer into said first layer.
Claim 2
Dependent Claim
161 words
A semiconductor device being at least a bipolar transistor comprising a first semiconductor layer of a first conductivity type; a second semiconductor layer adjoining said first layer and being of a lower doping concentration of said first conductivity type, said first and second layers forming a collector zone; a third semiconductor layer situated on said second layer and being of a second conductivity type, said third layer forming at least a portion of a base zone; an emitter zone of said first conductivity type formed in a surface of said third layer away from said second layer; and a recess including a first portion extending from said surface of said third layer through said third layer and at least along a major surface of said second layer for a predetermine distance to form a mesa-like base zone, and a second portion being a groove extending from said first portion at said second layer through said second layer into said first layer.
Claim 3
Dependent Claim
38 words
A semiconductor device according to claim 1, wherein said pre-determine distance separates said groove from an intersection between said second and third layers by a distance which is at least equal to a thickness of said second layer.
Claim 4
Dependent Claim
23 words
A semiconductor device according to claim 2, wherein said groove extends into said first layer by a depth of at least 10 μm.
Claim 5
Dependent Claim
36 words
A semiconductor device according to claim 2, wherein a thin semiconductor zone of said first conductivity type adjoins said groove at all areas thereof, said semiconductor zone having a higher doping concentration then said second layer.
Claim 6
Dependent Claim
17 words
A semiconductor device according to claim 4, wherein said semiconductor zone is at least 1 μm thick.
Claim 7
Dependent Claim
20 words
A semiconductor device according to claim 5, wherein said semiconductor zone has a thickness between 4.5 μm and 5.5 μm.
Claim 8
Dependent Claim
22 words
A semiconductor device according to claim 4, wherein said semiconductor zone has a thickness substantially equal to that of said emitter zone.
Claim 9
Dependent Claim
26 words
A semiconductor device according to claim 4, wherein said semiconductor zone has a doping concentration at least 1000 times higher than that of said second layer.
Claim 10
Dependent Claim
28 words
A semiconductor device according to claim 8, wherein said doping concentration of said semiconductor zone is at most 10 7 times higher than that of said second layer.
Claim 11
Dependent Claim
28 words
A semiconductor device according to claim 4, wherein said semiconductor zone has an average doping concentration of at most a factor 10 of that of said first layer.
Claim 12
Dependent Claim
36 words
A semiconductor device according to claim 1, wherein a thin semiconductor zone of said first conductivity type adjoins said groove at all areas thereof, said semiconductor zone having a higher doping concentration than said second layer.
Claim 13
Dependent Claim
17 words
A semiconductor device according to claim 11, wherein said semiconductor zone is at least 1 μm thick.
Claim 14
Dependent Claim
20 words
A semiconductor device according to claim 12, wherein said semiconductor zone has a thickness between 4.5 μm and 5.5 μm.
Claim 15
Dependent Claim
22 words
A semiconductor device according to claim 11, wherein said semiconductor zone has a thickness substantially equal to that of said emitter zone.
Claim 16
Dependent Claim
26 words
A semiconductor device according to claim 11, wherein said semiconductor zone has a doping concentration at least 1000 times higher than that of said second layer.
Claim 17
Dependent Claim
28 words
A semiconductor device according to claim 15, wherein said doping concentration of said semiconductor zone is at most 10 7 times higher than that of said second layer.
Claim 18
Dependent Claim
29 words
A semiconductor device according to claim 11, wherein said semiconductor zone has an average doping concentration of at most a factor 10 10 of that of said first layer.
References Cited (Backward Citations)
US4165516A
Cited
US4156250A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-03 | 1984-08-04 | 1985-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-03 | 1988-08-04 | 1989-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-03 | 1992-08-04 | 1993-02-03 | $7700.00 | Window Closed / Lapsed |