US5126830A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cryogenic semiconductor power devices
Assignee: General Electric Co
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Filing: 1989-10-31
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Granted: 1992-06-30
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Expires: 2009-10-31
Abstract
Abstract A cryogenic solid-state semiconductor power device, has the actual device chip mounted on a substrate of a material of very high thermal conductivity, which is positioned in a a bath of cryogenic fluid. The substrate may be formed of beryllia, beryllium, alumina, aluminum nitride, diamond and the like materials.
Inventors
- 👤 Otward M. Mueller
- 👤 Lowell S. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:39
CPC Classifications
H; H10; H10W; H10W40/00; H10W40/30; H10W40/305
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
181 words
A device for use in a cryogenic environment, comprising: a semiconductor power device chip; a substrate having a surface on which said chip is mounted, said substrate being substantially surrounded by a mass of cryogenic fluid; said substrate consisting of an electrically but thermally conductive material having greater thermal conductivity at cryogenic temperatures than at room temperature; said substrate having a thickness selected for optimum dissipation, at cryogenic temperatures, of chip-generated heat, said last-recited thickness being greater than the substrate thickness selected for optimum heat dissipation for device operation at room temperature; said substrate further comprising a recess in said surface for holding said semiconductor power device chip and means for providing a protective covering for said chip; a structural member disposed within said mass of cryogenic fluid substantially parallel to said substrate; and means for increasing the heat dissipation of said substrate including a base portion connected between said substrate and said structural member for spacing said substrate from said structural member, said base portion being effective to increase the surface area of said substrate exposed to said cryogenic fluid.
Claim 2
Independent Claim
181 words
A device for use in a cryogenic environment, comprising: a semiconductor power device chip; a substrate having a surface on which said chip is mounted, said substrate being substantially surrounded by a mass of cryogenic fluid; said substrate consisting of an electrically but thermally conductive material having greater thermal conductivity at cryogenic temperatures than at room temperature; said substrate having a thickness selected for optimum dissipation, at cryogenic temperatures, of chip-generated heat, said last-recited thickness being greater than the substrate thickness selected for optimum heat dissipation for device operation at room temperature; said substrate further comprising a recess in said surface for holding said semiconductor power device chip and means for providing a protective covering for said chip; a structural member disposed within said mass of cryogenic fluid substantially parallel to said substrate; and means for increasing the heat dissipation of said substrate including a base portion connected between said substrate and said structural member for spacing said substrate from said structural member, said base portion being effective to increase the surface area of said substrate exposed to said cryogenic fluid.
Claim 3
Dependent Claim
29 words
The device of claim 1, wherein said substrate is oriented in said cryogenic mass by said base portion to minimize the collection of barrier vapor adjacent to said surface.
Claim 4
Dependent Claim
17 words
The device of claim 1, wherein said semiconductor power device chip is a static induction transistor (SIT).
Claim 5
Dependent Claim
14 words
The device of claim 3, wherein the SIT is fabricated in a germanium chip.
Claim 6
Dependent Claim
16 words
The device of claim 1, wherein said semiconductor power device chip is a field-effect transistor (FET).
Claim 7
Dependent Claim
13 words
The device of claim 5, wherein said FET is a Metal-Oxide-Semiconductor FET (MOSFET).
Claim 8
Dependent Claim
22 words
The device of claim 1, wherein said substrate material is selected from the group consisting of beryllia, alumina, diamond and aluminum nitride.
Claim 9
Dependent Claim
26 words
The device of claim 1, wherein said semiconductor power device chip is fabricated from a material selected from the group consisting of silicon and gallium arsenide.
Claim 10
Dependent Claim
15 words
The device of claim 1, wherein the cryogenic fluid is liquid nitrogen (LN 2 ).
Claim 11
Independent Claim
156 words
A device for use in a cryogenic environment, comprising: a semiconductor power device chip; a substrate having a surface on which said chip is mounted, said substrate being substantially surrounded by a mass of cryogenic fluid; said substrate consisting of an electrically and thermally conductive material having greater thermal conductivity at cryogenic temperatures than at room temperature; said substrate having a thickness selected for optimum dissipation, at cryogenic temperatures, of chip-generated heat, said last-recited thickness being greater than the substrate thickness selected for optimum heat dissipation for device operation at room temperature; an electrically insulative structural member disposed in said mass of cryogenic fluid substantially parallel to said substrate; means for increasing the heat dissipation of said substrate including a base portion connected between said substrate and said structural member for spacing said substrate from said structural member, said base portion being effective to increase the surface area of said substrate exposed to said cryogenic fluid.
Claim 12
Independent Claim
156 words
A device for use in a cryogenic environment, comprising: a semiconductor power device chip; a substrate having a surface on which said chip is mounted, said substrate being substantially surrounded by a mass of cryogenic fluid; said substrate consisting of an electrically and thermally conductive material having greater thermal conductivity at cryogenic temperatures than at room temperature; said substrate having a thickness selected for optimum dissipation, at cryogenic temperatures, of chip-generated heat, said last-recited thickness being greater than the substrate thickness selected for optimum heat dissipation for device operation at room temperature; an electrically insulative structural member disposed in said mass of cryogenic fluid substantially parallel to said substrate; means for increasing the heat dissipation of said substrate including a base portion connected between said substrate and said structural member for spacing said substrate from said structural member, said base portion being effective to increase the surface area of said substrate exposed to said cryogenic fluid.
Claim 13
Dependent Claim
12 words
The device of claim 10 wherein said base portion is electrically insulative.
Claim 14
Dependent Claim
12 words
The device of claim 10, wherein said substrate consists essentially of beryllium.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-06-30 | 1995-12-30 | 1996-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-30 | 1999-12-30 | 2000-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-30 | 2003-12-30 | 2004-06-30 | $7700.00 | Window Closed / Lapsed |