US3611058A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Varactor diode
Assignee: Motors Liquidation Co
•
Filing: 1970-05-11
•
Granted: 1971-10-05
•
Expires: 1990-05-11
Abstract
Abstract This disclosure relates to a planar-type junction varactor, and a method for making same, having improved voltage breakdown and leakage current characteristics which can be used as a tuning element in vehicular-type battery operated AM radios. One form of the device can be made by successively depositing semiconductor layers of high and low resistivities onto a low-resistivity substrate including a substantially intrinsic layer, and forming a PN junction within the deposited layers extending to the front surface of the device. A groove from the active surface of the device down to the substrate permits coplanar ohmic contacts on the active surface of the device.
Inventors
- 👤 Larry Lee Jordan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:49
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/60; H10D1/62; H10D1/64; Y; Y10; Y10S; Y10S148/00; Y10S148/085
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
194 words
A planar-type junction varactor having desired leakage current and breakdown voltage characteristics which comprises a semiconductor laminate having an active surface and a back surface, said laminate including an N+ substrate forming said back surface, an N- epitaxial layer on said substrate layer, an N+ epitaxial layer on said N- epitaxial layer, a substantially intrinsic surface layer of N-type conductivity on said N+ epitaxial layer and forming said active surface, a P+ region within said N+ layer and said surface layer providing a PN junction spaced from said N- epitaxial layer and extending to said active surface, the average resistivity of said P+ region being an order of magnitude less than the average resistivity of said N+ layer, said laminate having a groove circumferentially spaced outwardly from said PN junction extending from said active surface to said substrate, a first contact on said active surface making ohmic connection to said P+ region and a second contact in said groove making ohmic connection with said substrate and extending out of the groove over the contiguous portion of said active surface, the second contact thereby being generally coplanar with the first contact on said active surface.
Claim 2
Dependent Claim
212 words
A planar-type junction varactor tuning device for a battery-operated AM radio having desired leakage current and breakdown voltage characteristics which device comprisEs a silicon laminate having an active surface and a back surface, said laminate including an N+ substrate layer forming said back surface, about a 10 micron thick N- epitaxial layer on said substrate, about 0.5 micron thick N+ conductivity epitaxial layer on said N- epitaxial layer, about a 0.5 micron thick substantially intrinsic surface of N-type conductivity on said second layer and forming said active surface, a P+ region within said N+ and said surface layers which extends about 0.7 microns into said laminate and terminates on said active surface, the average resistivity of said region being an order of magnitude less than the resistivity of said N+ layer, said laminate having a groove surrounding noncontiguously said PN junction extending from said active surface to said substrate layer, a first contact on said active surface making ohmic connection to said P+ region and a second contact spaced from said first contact in said groove making an ohmic connection with said substrate and extending out of said groove over a contiguous portion of said active surface, the second contact thereby being generally coplanar with the first contact on said active surface.
Claim 3
Independent Claim
156 words
A method of making a planar-type junction varactor comprising the steps of, epitaxially depositing a high-resistivity silicon layer on said substrate within an epitaxial reactor by introducing N-type impurities into the reactor at a first predetermined rate, epitaxially depositing a low-resistivity silicon layer on said high-resistivity layer by introducing N-type impurities into the reactor at an increased rate, terminating the flow of N-type impurities into the epitaxial reactor, epitaxially depositing a substantially intrinsic surface layer of silicon on the low-resistivity layer of silicon, forming a P-type region having a resistivity of at least an order of magnitude lower than said low-resistivity layer within said surface layer and said low-resistivity layer, etching a groove spaced from said P-type region through said epitaxial depositions to said substrate, forming separate metallic contacts onto said P-type region and in said groove and on the surface layer contiguous to said groove making ohmic connection to said P-type region and said substrate.
Claim 4
Independent Claim
174 words
A method of making a planar-type junction varactor having desired leakage current and voltage breakdown characteristics comprising the steps of, epitaxially depositing about a 10 micron N- silicon layer on a N+ substrate within an epitaxial reactor by introducing N-type impurities into the reactor at a first predetermined rate, epitaxially depositing about a 0.5 micron N+ silicon layer on the 10 micron layer by introducing N-type impurities into the reactor at an increased rate, terminating the flow of N-type impurities into the epitaxial reactor, epitaxially depositing about 0.5 micron substantially intrinsic surface layer of silicon on the N+ layer of silicon, forming a P+ region within said surface layer and said N+ layer having a resistivity of at least an order of magnitude lower than the N+ layer, etching a groove through said epitaxial depositions to said substrate noncontiguously surrounding said P-type region, forming separate metallic contacts onto said P-type region and in said groove and on the surface layer contiguous to said groove making ohmic connection to said P-type region and 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) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |