Patent US3634738A successfully refreshed from Google Patents.
US3634738A
Expired / Lapsed
US
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Diode having a voltage variable capacitance characteristic and method of making same
Assignee: Kev Electronics Corp
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Filing: 1970-10-06
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Granted: 1972-01-11
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Expires: 1990-10-06
Abstract
Abstract In the method of the present invention, a lightly doped layer of semiconductive material is epitaxially grown on a relatively highly doped substrate so as to provide a relatively sharply defined transition in conductivity between the epitaxial layer and the original substrate material. Further, additional dopant material of the same conductivity type is implanted into the layer by particle bombardment thereby to provide a conductivity profile in which conductivity decreases with depth through the layer substantially down to the essentially uniform conductivity of the original epitaxial material. A dopant providing conductivity of the opposite type is diffused into a relatively shallow portion of the epitaxial layer so as to form a diode junction in the layer. In the diode so formed, the depth of the depletion region varies as a predictable function of the controlled conductivity profile in the epitaxial layer. Since the substrate provides a region of high conductivity just beyond the epitaxial layer, the Q of the device is relatively high.
Inventors
- 👤 Frank A Leith
- 👤 Carl H Guild Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:20
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/60; H10D1/62; H10D1/64
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
25 words
The method of making a diode as set forth in claim 1 wherein said semiconductor substrate and said epitaxial layer grown thereupon are essentially silicon.
Claim 2
Dependent Claim
19 words
The method of making a diode as set forth in claim 2 wherein said substrate is doped with antimony.
Claim 3
Dependent Claim
20 words
The method of making a diodE as set forth in claim 2 wherein said epitaxial layer is doped with phosphorous.
Claim 4
Dependent Claim
20 words
The method of making a diode as set forth in claim 2 wherein said dopant providing second-type conductivity is boron.
Claim 5
Independent Claim
206 words
The method of making a diode, the capacitance of which is voltage variable, said method comprising: providing a silicon substrate which is relatively highly doped to provide conductivity of a first type; epitaxially growing on said substrate, by reducing a silane atmosphere, a silicon layer which is relatively lightly doped to provide conductivity of said first type, there being a relatively sharply defined transition in conductivity between said epitaxial layer and the original substrate material; diffusing into a relatively shallow portion of said epitaxial layer, from a boron-doped glass deposit, a relatively high concentration of a dopant providing conductivity of a second type, complementary to said first type; implanting into said layer, through and beyond said shallow portion thereof, ions of a dopant material providing conductivity of said first type, the energy level at which the ions are implanted being selected to provide a peak concentration approximately coincident with the edge of said shallow portion of second-type conductivity, whereby, when said shallow portion of second-type conductivity is reverse biased with respect to said substrate and the balance of said epitaxial layer, the thickness of the depletion region and the capacitance of the diode vary as precisely predictable functions of the conductivity profile provided by said implantation.
Claim 6
Independent Claim
190 words
The method of making a diode, the capacitance of which is voltage variable, said method comprising: providing a silicon substrate which is relatively highly doped to provide N-type conductivity; epitaxially growing on said substrate, by reducing a silane atmosphere, a silicon layer which is relatively lightly doped to provide N-type conductivity, there being a relatively sharply defined transition in conductivity between said epitaxial layer and the original substrate material; diffusing into a relatively shallow portion of said epitaxial layer, from a boron-doped glass deposit, a relatively high concentration of a boron to provide P-type conductivity; implanting into said layer, through and beyond said shallow portion thereof, ions of phosphorous to provide increased N-type conductivity, the energy level at which the ions are implanted being selected to provide a peak concentration approximately coincident with the edge of said shallow portion of P-type conductivity, whereby, when said shallow portion of P-type conductivity is reverse biased with respect to said substrate and the balance of said epitaxial layer, the thickness of the depletion region and the capacitance of the diode vary as precisely predictable functions of the conductivity profile provided by said implantation.
Claim 7
Dependent Claim
166 words
A semiconductor diode having a voltage variable capacitance characteristic, said diode comprising: a substrate relatively highly doped to provide a first conductivity type; on said substrate, and epitaxial layer of said first conductivity type having doping material which is relatively light relative to the doping of said substrate, the first conductivity type doping material in said layer following a distribution profile which increases from the surface for a distance below the surface and decreases beoynd said distance through said layer substantially down to the level of the epitaxial material, said epitaxial layer having a relatively shallow heavy doping of a second conductivity type doping material adjacent its surface, the depth of the second conductivity type doping material being approximately equal to said distance whereby, when said shallow portion of said layer is reverse biased with respect to said substrate and the balance of said layer, the thickness of the depletion region and the capacitance of the diode vary as precisely predictable functions of Said conductivity profile.
Claim 8
Dependent Claim
164 words
A semiconductor diode having a voltage variable capacitance characteristic, said diode comprising: a substrate relatively highly doped to provide a first conductivity type; on said substrate a relatively lightly doped first conductivity type epitaxial layer adjacent said substrate and providing a relatively sharply defined transition in conductivity between said epitaxial layer and the substrate material, a relatively shallow portion of said epitaxial layer being of second conductivity type with a relatively high concentration of doping material; and implanted into said layer, through and beyond said shallow portion thereof, ions of a dopant material providing conductivity of said first type, said implanted ions providing a conductivity profile which decreases with depth through said layer for a distance beyond said shallow portion whereby, when said shallow portion of second-type conductivity is reverse biased with respect to said substrate and the balance of said epitaxial layer, the thickness of the depletion region and the capacitance of the diode vary as precisely predicatble functions of said conductivity profile.
Claim 9
Dependent Claim
163 words
A semiconductor diode having a voltage variable capacitance characteristic, said diode comprising: a silicon substrate relatively highly doped to provide N-type conductivity; on said substrate a relatively lightly doped N-type conductivity epitaxial layer of silicon adjacent said substrate providing a relatively sharply defined transition in conductivity between said epitaxial layer and the substrate material, a relatively shallow portion of said epitaxial layer being of P-type conductivity provided by a relatively high concentration of boron dopant; and implanted into said layer, through and beyond said shallow portion thereof, phoshorous ions providing N-type conductivity, said implanted ions providing an N-type conductivity profile which reaches a maximum value approximately at the edge of said shallow portion, whereby, when said shallow portion of P-type conductivity is reverse biased with respect to said substrate and the balance of said epitaxial layer, the thickness of the depletion region and the capacitance of the diode vary as precisely predictable functions of the N-type conductivity profile provided by the implanted ions.
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) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |