Patent US5900648A successfully refreshed from Google Patents.
US5900648A
Expired / Lapsed
US
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Semiconductor device having an insulated gate
Assignee: Wolfspeed Inc
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Filing: 1997-03-28
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Granted: 1999-05-04
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Expires: 2017-03-28
Abstract
Abstract A semiconductor device comprises a semiconductor layer of SiC and an insulating layer thereon for insulating the SiC layer with respect to a metal plate constituting a gate and connectable to a voltage for creating a conducting surface channel at a SiC layer-insulating layer interface, wherein at least a portion of the insulating layer closest to the interface is made of a crystalline material which is substantially lattice-matched to SiC and has substantially the same coefficient of thermal expansion as SiC; and wherein the material has AlN as the only component or as a major component of an alloy with insulating properties.
Inventors
- 👤 Christopher Harris
- 👤 Andrei Konstantinov
- 👤 Erik Janzen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:26
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/60; H10D30/64; H10D30/66; H10D12/00; H10D12/411; H10D12/441; H10D30/80; H10D30/801; H10D62/00; H10D62/80; H10D62/83; H10D62/832; H10D62/8325; H10D64/00; H10D64/60; H10D64/602; H10D64/66; H10D64/68; H10D64/681; H10D64/693
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
140 words
A semiconductor device comprising: a semiconductor layer of crystalline SiC; an insulating layer arranged on said SiC layer; a metal layer constituting a gate contact arranged directly on said insulating layer; said insulating layer for insulating the SiC layer with respect to said gate contact, said gate being connectable to a voltage for creating a conducting surface channel at a SiC layer-insulating layer interface; wherein at least a portion of the insulating layer closest to said interface is made of a crystalline material which is lattice-matched to SiC and has substantially the same coefficient of thermal expansion as SiC; and wherein said insulating material has AlN as the only component or as a major component of an alloy with insulating properties, and has a larger gap between the conduction band and the valence band than said semiconductor layer of SiC.
Claim 2
Dependent Claim
140 words
A semiconductor device comprising: a semiconductor layer of crystalline SiC; an insulating layer arranged on said SiC layer; a metal layer constituting a gate contact arranged directly on said insulating layer; said insulating layer for insulating the SiC layer with respect to said gate contact, said gate being connectable to a voltage for creating a conducting surface channel at a SiC layer-insulating layer interface; wherein at least a portion of the insulating layer closest to said interface is made of a crystalline material which is lattice-matched to SiC and has substantially the same coefficient of thermal expansion as SiC; and wherein said insulating material has AlN as the only component or as a major component of an alloy with insulating properties, and has a larger gap between the conduction band and the valence band than said semiconductor layer of SiC.
Claim 3
Dependent Claim
45 words
A device according to claim 1, wherein said material has placed next to the SiC of the semiconductor layer a higher energy level of a conduction band at said interface than an energy level of a conduction band of the SiC semiconductor at said interface.
Claim 4
Dependent Claim
45 words
A device according to claim 1, wherein said material has placed next to the SiC of the semiconductor layer a lower energy level of a valence band at said interface than an energy level of a valence band of the SiC semiconductor at said interface.
Claim 5
Dependent Claim
11 words
A device according to claim 1, wherein said material is AlN.
Claim 6
Dependent Claim
19 words
A device according to claim 1, wherein said material has a composition changing with a distance from said interface.
Claim 7
Dependent Claim
16 words
A device according to claim 1, wherein a whole insulating layer is made of said material.
Claim 8
Dependent Claim
12 words
A device according to claim 2, wherein said semiconductor layer is P-doped.
Claim 9
Dependent Claim
12 words
A device according to claim 3, wherein said semiconductor layer is N-doped.
Claim 10
Dependent Claim
14 words
a device according to claim 1, wherein said semiconductor layer is made of 6H-SiC.
Claim 11
Dependent Claim
13 words
A device according to claim 1, wherein said device is a bipolar device.
Claim 12
Dependent Claim
9 words
A device according to claim 10, being an IGBT.
Claim 13
Dependent Claim
13 words
A device according to claim 1, wherein said device is a unipolar device.
Claim 14
Dependent Claim
68 words
A device according to claim 1, wherein said semiconductor layer is a first layer arranged adjacent to and between a second semiconductor layer and a third semiconductor layer, wherein the insulating layer extends from the second semiconductor layer to the third semiconductor layers and wherein said gate voltage is adapted to create said surface channel at said interface between said second semiconductor layer and said third semiconductor layer.
Claim 15
Dependent Claim
22 words
A semiconductor device according to claim 1 wherein said semiconductor layer is made of monocrystalline SiC and said material is monocrystalline material.
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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) | 2002-05-03 | 2002-11-02 | 2003-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-03 | 2006-11-02 | 2007-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-03 | 2010-11-02 | 2011-05-04 | $7700.00 | Window Closed / Lapsed |