US3582724A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transistor having concave collector contact and method of making same
Assignee: Sanyo Electric Co Ltd
•
Filing: 1968-09-13
•
Granted: 1971-06-01
•
Expires: 1988-09-13
Abstract
Abstract A switching transistor element of the concave collector contact structure and having excellent second breakdown characteristics and a method of making such a transistor by forming the concave collector contact by the alloying method using a jig comprising a projection, by the diffusion method which employs two kinds of impurities having different diffusion constants or by the epitaxial growth method using a substrate to which a concave part is provided in advance.
Inventors
- 👤 Osamu Nakahara
- 👤 Kazuyoshi Goto
- 👤 Masahiko Horiguchi
- 👤 Tatsuya Ishihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:37
CPC Classifications
H; H10; H10D; H10D99/00; B; B27; B27D; B27D1/00; B27D1/04; H10D10/00; H10P; H10P95/00; Y; Y10; Y10S; Y10S148/00; Y10S148/037; Y10S148/145; Y10S148/151; Y10S438/00; Y10S438/965
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
18 words
A transistor as in claim 1 wherein said protruding portion of said collector layer is annular in shape.
Claim 2
Dependent Claim
30 words
A transistor as in claim 1 wherein said collector contact is of a material having a resistivity which is lower than the resistivity of the material forming the collector layer.
Claim 3
Dependent Claim
37 words
A transistor as in claim 1 wherein the area of the recess of said collector contact is at least 10 percent of the area of the collector contact which is in electrical contact with the collector layer.
Claim 4
Dependent Claim
73 words
A transistor as in claim 1 wherein the height from the top of said protrusion of said collector layer to said junction of said base and collector layers ( omega 1) and the height from the portion of the collector contact adjacent said other surface of said collector layer surrounding said protruding portion to said junction of said base and collector layers has a ( omega 2) ratio equal to at least 1.2.
Claim 5
Dependent Claim
33 words
A transistor as in claim 1 wherein the collector layer is formed with a recessed area at least partially around said protruding portion, said collector contact also being located in said recessed area.
Claim 6
Dependent Claim
24 words
A transistor as in claim 1 wherein the remainder of said other surface of said collector layer below said protruding portion is generally planar.
Claim 7
Dependent Claim
23 words
A transistor as in claim 1 wherein said protruding portion of said collector layer has a height of at least 10 Mu .
Claim 8
Dependent Claim
31 words
A transistor as in claim 1 wherein said collector contact makes electrical contact with the protruding portion of said collector layer over substantially the entire exposed surface of said protruding portion.
References Cited (Backward Citations)
US2813817A
Cited
US3220896A
Cited
US3253197A
Cited
US3260902A
Cited
US3377527A
Cited
FR1450952A
Cited
US3414783A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |