Patent US3609476A successfully refreshed from Google Patents.
US3609476A
Expired / Lapsed
US
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Interdigitated structures for gate turnoff thyristors and for transistors
Assignee: General Electric Co
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Filing: 1970-06-26
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Granted: 1971-09-28
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Expires: 1990-06-26
Abstract
Abstract An interdigitated emitter-base (or emitter-gate) layer structure is formed in the shape of an involute on a circular wafer. Because of greater wafer utilization, higher power ratings in semiconductor devices are realized. The contours of the involuteshaped interdigitated emitter and base contact elements are identical, simplifying mask preparation, and assuring simultaneous turnoff of the entire junction area in a gate turnoff thyristor, and simultaneous turn on in a transistor.
Inventors
- 👤 Herbert F Storm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:25
CPC Classifications
H; H10; H10D; H10D18/00; H10D18/60; H10D64/00; H10D64/20; H10D64/27; H10D64/281; H10D64/291; H10D99/00
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
43 words
A structure as set forth in claim 1 wherein said inner semiconductor layer is circular, and the evolute of the involutes defining said involute-shaped control current contact elements and outer semiconductor layer elements is centered at the center of said inner semiconductor layer.
Claim 2
Dependent Claim
34 words
A structure as set forth in claim 2 wherein said contact means effecting parallel electrical connection of said control current contact elements is formed on said inner semiconductor layer within the centrally located evolute.
Claim 3
Dependent Claim
36 words
A structure as set forth in claim 2 wherein said contact means effecting parallel electrical connection of said control current contact elements is a ring-shaped contact formed on said circular inner semiconductor layer adjacent its periphery.
Claim 4
Dependent Claim
39 words
A structure as set forth in claim 2 wherein said contact means effecting parallel electrical connection of said control current contact elements is a ring-shaped contact formed on said circular inner semiconductor layer between its periphery and said evolute.
Claim 5
Dependent Claim
21 words
A structure as set forth in claim 5 wherein the involutes on either side of said ring-shaped contact are oppositely sloped.
Claim 6
Dependent Claim
45 words
A structure as set forth in claim 1 wherein said inner semiconductor layer is circular, and the evolute of the involutes defining said involute-shaped control current contact elements and outer semiconductor layer elements is a circle centered at the center of said inner semiconductor layer.
Claim 7
Dependent Claim
47 words
A structure as set forth in claim 7 wherein said involute-shaped control current contact elements and outer semiconductor layer elements have unequal widths, and said contact means effecting parallel electrical connection of said control current contact elements is formed on said inner semiconductor layer within said evolute.
Claim 8
Dependent Claim
29 words
A structure as set forth in claim 7 wherein the beginning of said involute-shaped control current contact elements and outer semiconductor layer elements is radially outward from said evolute.
Claim 9
Dependent Claim
99 words
A power semiconductor device of the type having a base control current terminal comprising a circular multilayer semiconductor wafer including a base layer of one conductivity type, a plurality of elongated interdigitated base control current contact elements and emitter semiconductor elements of the opposite conductivity type respectively having equal constant widths, wherein said alternating base contact elements and emitter elements are involute-shaped and formed parallel to one another on the surface of said base layer, and contact means for effecting parallel electrical connection of said involute-shaped emitter elements and independent parallel electrical connection of said involute-shaped base contact elements.
Claim 10
Dependent Claim
33 words
A structure as set forth in claim 10 wherein the evolute of the involutes defining said involute-shaped base contact elements and emitter elements is a circle at the center of said base layer.
Claim 11
Dependent Claim
48 words
A structure as set forth in claim 11 wherein the beginning of said involute-shaped base contact elements and emitter elements is at the evolute circle, and said contact means effecting parallel electrical connection of said base contact elements if formed on said base layer within the evolute circle.
Claim 12
Dependent Claim
31 words
A structure as set forth in claim 12 wherein said semiconductor wafer comprises only a collector layer in addition to said base layer, and said semiconductor device is a power transistor.
Claim 13
Dependent Claim
33 words
A structure as set forth in claim 12 wherein said semiconductor wafer has two semiconductor layers in addition to said base layer, and said semiconductor device is a four-layer power gate turnoff thyristor.
Claim 14
Dependent Claim
28 words
A structure as set forth in claim 12 wherein the ends of said involute-shaped emitter elements are reduced in width near the periphery of said circular semiconductor wafer.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-27 | 1975-03-29 | 1975-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-27 | 1979-03-29 | 1979-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-27 | 1983-03-29 | 1983-09-28 | $7700.00 | Window Closed / Lapsed |