US3663874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Impatt diode
Assignee: Fujitsu Ltd
•
Filing: 1969-10-06
•
Granted: 1972-05-16
•
Expires: 1989-10-06
Abstract
Abstract A high resistance semiconductor epitaxial layer of opposite conductivity type is provided on a lower resistance semiconductor substrate of one conductivity type. A first diffusion layer of the one conductivity type and of cylindrical configuration extends through the epitaxial layer from the substrate in a limited area. A second diffusion layer of the opposite conductivity type and of disc-like configuration extends from the outer surface of the first diffusion layer a limited distance into the first diffusion layer in a manner whereby the junction between the first and second diffusion layers is planar and is embedded in the diode and has a breakdown voltage which is lower than that of the junction between the substrate and the epitaxial layer. Avalanche breakdown occurs substantially at the junction between the first and second diffusion layers.
Inventors
- 👤 Yukio Fukukawa
- 👤 Masaichi Shinoda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:54
CPC Classifications
H; H10; H10W; H10W40/00; H10W40/10; H10D; H10D99/00; H10W72/00; Y; Y10; Y10S; Y10S148/00; Y10S148/035; Y10S148/144; Y10S148/145
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
206 words
An IMPATT diode, comprising a low resistance semiconductor substrate of one conductivity type having a flat surface and an opposite surface; a semiconductor epitaxial layer formed on the flat surface of the substrate, said epitaxial layer being of high resistance and of opposite conductivity type from said substrate; a first diffusion layer of the same conductivity type as the substrate extending from the substrate a specific distance into the epitaxial layer, a second diffusion layer of the same conductivity type as the epitaxial layer and having a higher impurity concentration than the epitaxial layer and of substantially disc-like configuration, the second diffusion layer being coaxially positioned with said first diffusion layer and having a diameter greater than that of said first diffusion layer and ends within the epitaxial layer in contact with the first diffusion layer and having a flat and embedded junction part formed within the epitaxial layer by the first and second diffusion layers thereby having a breakdown voltage lower than the breakdown voltage of the other junction parts whereby the avalanche occurs substantially in the flat and embedded junction part; a heat sink bonded to the surface of the epitaxial layer; and electrical means extending from the opposite surface of the semiconductor substrate.
Claim 2
Dependent Claim
206 words
An IMPATT diode, comprising a low resistance semiconductor substrate of one conductivity type having a flat surface and an opposite surface; a semiconductor epitaxial layer formed on the flat surface of the substrate, said epitaxial layer being of high resistance and of opposite conductivity type from said substrate; a first diffusion layer of the same conductivity type as the substrate extending from the substrate a specific distance into the epitaxial layer, a second diffusion layer of the same conductivity type as the epitaxial layer and having a higher impurity concentration than the epitaxial layer and of substantially disc-like configuration, the second diffusion layer being coaxially positioned with said first diffusion layer and having a diameter greater than that of said first diffusion layer and ends within the epitaxial layer in contact with the first diffusion layer and having a flat and embedded junction part formed within the epitaxial layer by the first and second diffusion layers thereby having a breakdown voltage lower than the breakdown voltage of the other junction parts whereby the avalanche occurs substantially in the flat and embedded junction part; a heat sink bonded to the surface of the epitaxial layer; and electrical means extending from the opposite surface of the semiconductor substrate.
Claim 3
Dependent Claim
26 words
An IMPATT diode as claimed in claim 1, wherein said one conductivity type is N conductivity type and said opposite conductivity type is P conductivity type.
Claim 4
Dependent Claim
14 words
An IMPATT diode as claimed in claim 1, wherein said semiconductor substrate comprises silicon.
Claim 5
Dependent Claim
20 words
An IMPATT diode as claimed in claim 1, wherein said first diffusion layer extends a limited distance into said substrate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-16 | 1975-11-15 | 1976-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-16 | 1979-11-15 | 1980-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-16 | 1983-11-15 | 1984-05-16 | $7700.00 | Window Closed / Lapsed |