US3974515A
Expired / Lapsed
US
⏱️ 0.0 years remaining
IGFET on an insulating substrate
Assignee: RCA Corp
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Filing: 1974-09-12
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Granted: 1976-08-10
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Expires: 1994-09-12
Abstract
Abstract The breakdown voltage of a novel insulated gate field effect transistor (IGFET), comprising silicon on sapphire (SOS), is substantially doubled by a novel structure wherein a dielectric layer, formed over a channel region of the IGFET, also extends continuously over the surface of the sapphire on opposite sides of the channel region. A polysilicon gate electrode is disposed over the dielectric layer, the gate electrode extending beyond the channel region and being separated from the sapphire substrate by the dielectric layer. The novel method of making the IGFET comprises providing an island of epitaxially deposited doped silicon on the sapphire substrate, and dielectric layer extending continuously over both the island and over portions of the substrate on opposite sides of the island.
Inventors
- 👤 Alfred Charles Ipri
- 👤 Joseph Hurlong Scott
- 👤 John Carl Sarace
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:25
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/67; H10D30/6758; H10D30/6759; H10D30/6729; H10D30/6737; H10D30/6739; H10D86/00; H10D86/01; H10D86/03; Y; Y10; Y10S; Y10S148/00; Y10S148/02; Y10S148/053; Y10S148/085; Y10S148/122; Y10S148/15
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
138 words
An IGFET comprising: an electrically insulating substrate having a surface, an island of single-crystal silicon on a portion of said surface, having source and drain regions of one type conductivity at opposite ends thereof, respectively, and having a channel region of the opposite type conductivity intermediate said source and drain regions and adjacent to the surface of said island away from said substrate, a dielectric layer over said channel region and continuous over said surface of said substrate on opposite sides of said channel region and extending away therefrom, said opposite sides being along the same direction as the flow of conductivity modifiers in said channel region, and a gate electrode over said dielectric layer, said gate electrode extending beyond said channel region away from said opposite sides and being separated from said substrate by said dielectric layer.
Claim 2
Dependent Claim
138 words
An IGFET comprising: an electrically insulating substrate having a surface, an island of single-crystal silicon on a portion of said surface, having source and drain regions of one type conductivity at opposite ends thereof, respectively, and having a channel region of the opposite type conductivity intermediate said source and drain regions and adjacent to the surface of said island away from said substrate, a dielectric layer over said channel region and continuous over said surface of said substrate on opposite sides of said channel region and extending away therefrom, said opposite sides being along the same direction as the flow of conductivity modifiers in said channel region, and a gate electrode over said dielectric layer, said gate electrode extending beyond said channel region away from said opposite sides and being separated from said substrate by said dielectric layer.
Claim 3
Dependent Claim
32 words
An IGFET as defined in claim 1, wherein: said electrically insulating substrate is an electrical insulator chosen from the group consisting of sapphire and spinel, and said dielectric layer comprises silicon oxide.
Claim 4
Dependent Claim
46 words
An IGFET as defined in claim 1, wherein: said dielectric layer comprises the reaction product of the oxidation of silicon that has been deposited on said substrate, and said gate electrode is a metal chosen from the group consisting of aluminum, molybdenum, tungsten, and alloys thereof.
Claim 5
Dependent Claim
14 words
An IGFET as defined in claim 1, wherein: said gate electrode comprises doped polysilicon.
Claim 6
Dependent Claim
27 words
An IGFET as defined in claim 4, wherein: a passivating layer, comprising dopant means for said gate electrode, is deposited over said gate electrode and said island.
Claim 7
Dependent Claim
14 words
An IGFET as defined in claim 1, wherein: said dielectric layer comprises silicon nitride.
Claim 8
Dependent Claim
14 words
An IGFET as defined in claim 1, wherein: said dielectric layer comprises aluminum oxide.
Claim 9
Dependent Claim
15 words
An IGFET as defined in claim 1, wherein: said dielectric layer comprises vapor-deposited silicon oxide.
Claim 10
Dependent Claim
43 words
An IGFET as defined in claim 1, wherein: said dielectric layer is a composite of a layer of thermally grown silicon oxide and a layer of a dielectric material chosen from the group consisting of vapor-deposited silicon oxide, silicon nitride, and aluminum oxide.
References Cited (Backward Citations)
US3191061A
Cited
US3890632A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-10 | 1980-02-09 | 1980-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-10 | 1984-02-09 | 1984-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-10 | 1988-02-09 | 1988-08-10 | $7700.00 | Window Closed / Lapsed |