US4538165A
Expired / Lapsed
US
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FET With heterojunction induced channel
Assignee: International Business Machines Corp
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Filing: 1984-03-05
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Granted: 1985-08-27
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Expires: 2004-03-05
Abstract
Abstract The mobility of carriers in the channel region of a field effect transistor can be increased by providing a layered structure wherein electrons are separated from impurities. The channel is made up of external layers of wide bandgap material and internal layers with a narrower bandgap where the bottom of the conduction band of one layer is below the top of the valence band of the adjacent layer. A structure is shown with a layered channel having AlSb external layers and at least one or both of InAs and GaSb internal layers.
Inventors
- 👤 Chin-An Chang
- 👤 Leroy L. Chang
- 👤 Leo Esaki
- 👤 Emilio E. Mendez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:46
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/60; H10D64/602; H10D30/00; H10D30/40; H10D30/47; H10D30/471; H10D30/473; H10D30/4732; H10D62/00; H10D62/10; H10D62/17; H10D62/213; H10D62/221
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
106 words
In a field effect transistor of the type wherein current in a channel region is influenced by a voltage signal applied to a gate electrode over said channel, the improvement comprising a channel structure of contiguous undoped layers of semiconductor materials wherein an external material is provided between said gate electrode and said channel having a bandgap higher than that of the combined bandgaps of the semiconductor material layers of the conductive channel region and having the further requirement that the conduction band of a first layer of said channel is located below the top of the valence band of a second layer of said channel.
Claim 2
Dependent Claim
106 words
In a field effect transistor of the type wherein current in a channel region is influenced by a voltage signal applied to a gate electrode over said channel, the improvement comprising a channel structure of contiguous undoped layers of semiconductor materials wherein an external material is provided between said gate electrode and said channel having a bandgap higher than that of the combined bandgaps of the semiconductor material layers of the conductive channel region and having the further requirement that the conduction band of a first layer of said channel is located below the top of the valence band of a second layer of said channel.
Claim 3
Dependent Claim
57 words
In a field effect transistor of the type wherein current in a channel region is influenced by a voltage signal applied to a gate electrode over said channel, the improvement comprising a channel structure of contiguous undoped layers of InAs and GaSb semiconductor materials including an external material of AlSb between said gate electrode and said channel.
Claim 4
Dependent Claim
57 words
In a field effect transistor of the type wherein current in a channel region is influenced by a voltage signal applied to a gate electrode over said channel, the improvement comprising a channel structure of contiguous undoped layers of InAs and GaSb semiconductor materials including an external material of AlSb between said gate electrode and said channel.
Claim 5
Dependent Claim
115 words
A field effect transistor having a source and a drain electrode separated by a monocrystalline channel region said channel region having a conductive region of contiguous epitaxial first and second undoped layers of semiconductor materials such that the bottom of the conduction band of said first layer is located below the top of the valence band of said second layer, said channel region having at least one external layer of a semiconductor material extending from source to drain, epitaxial with said central region and having a band gap higher than the combined band gaps of said first and second layers of said conductive region, and a gate electrode essentially coextensive with each said external layer.
Claim 6
Dependent Claim
115 words
A field effect transistor having a source and a drain electrode separated by a monocrystalline channel region said channel region having a conductive region of contiguous epitaxial first and second undoped layers of semiconductor materials such that the bottom of the conduction band of said first layer is located below the top of the valence band of said second layer, said channel region having at least one external layer of a semiconductor material extending from source to drain, epitaxial with said central region and having a band gap higher than the combined band gaps of said first and second layers of said conductive region, and a gate electrode essentially coextensive with each said external layer.
Claim 7
Dependent Claim
72 words
A field effect transistor having a source and a drain electrode separated by a monocrystalline channel region said channel region having a conductive region of contiguous epitaxial first and second undoped layers of InAs and GaSb semiconductor materials, said channel region having at least one external layer of AlSb semiconductor material extending from source to drain, epitaxial with said central region, and a gate electrode essentially coextensive with each said external layer.
Claim 8
Dependent Claim
72 words
A field effect transistor having a source and a drain electrode separated by a monocrystalline channel region said channel region having a conductive region of contiguous epitaxial first and second undoped layers of InAs and GaSb semiconductor materials, said channel region having at least one external layer of AlSb semiconductor material extending from source to drain, epitaxial with said central region, and a gate electrode essentially coextensive with each said external layer.
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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) | 1988-08-26 | 1989-02-25 | 1989-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-26 | 1993-02-25 | 1993-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-26 | 1997-02-25 | 1997-08-27 | $7700.00 | Window Closed / Lapsed |