US4780748A
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Field-effect transistor having a delta-doped ohmic contact
Assignee: Nokia Bell Labs
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Filing: 1986-06-06
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Granted: 1988-10-25
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Expires: 2006-06-06
Abstract
Abstract A field-effect transistor is created on a GaAs semi-insulating substrate using molecular beam epitaxy by fabricating a delta-doped monolayer with a silicon dopant between two undoped GaAs layers grown over the semi-insulating substrate. A plurality of delta-doped monolayers are grown over the surface of the upper undoped layer interleaved with layers of GaAs having a thickness equal to or less than the tunneling width of electrons in GaAs. A channel is etched through the plurality of delta-doped monolayers to permit a gate electrode to contact the upper undoped GaAs layer. Source and drain electrodes are deposited over the delta-doped monolayers on each side of the channel.
Inventors
- 👤 John E. Cunningham
- 👤 Erdmann F. Schubert
- 👤 Won-Tien Tsang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:02
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/80; H10D62/85; H10D62/10; H10D62/13; H10D62/149; H10D62/161; H10D64/00; H10D64/60; H10D64/62; H10P; H10P14/00; H10P14/20; H10P14/22; H10P14/24; H10P14/29; H10P14/2901; H10P14/2907; H10P14/2911; H10P14/32; H10P14/3202; H10P14/3204; H10P14/3211; H10P14/3214; H10P14/3221; H10P14/3242; H10P14/3244; H10P14/3246; H10P14/3251; H10P14/3252; H10P14/34; H10P14/3402; H10P14/3414; H10P14/3421; H10P14/3438; H10P14/3441
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
156 words
A field-effect transistor comprising a substrate of semi-insulating semiconductor material, first layer of said semiconductor material grown over said substrate, second layer of said semiconductor material grown over said first layer, at least one delta-doped monolayer having a predetermined dopant juxtaposed between said first and second semiconductor layers, and source, gate and drain electrodes fabricated from a metallic conducting material, characterized in that a plurality of delta-doped monolayers are interposed between said source and drain electrodes and said second semiconductor layer, said plurality of delta-doped monolayers being separated from each other and from the source and drain electrodes by layers of semiconductor material each one of which has a thickness equal to or less than the tunneling width of electrons in said semiconductor material, and said gate electrode is positioned in a channel that is cut through said plurality of delta-doped monolayers such that the gate electrode is in direct contact with said second semiconductor layer.
Claim 2
Dependent Claim
156 words
A field-effect transistor comprising a substrate of semi-insulating semiconductor material, first layer of said semiconductor material grown over said substrate, second layer of said semiconductor material grown over said first layer, at least one delta-doped monolayer having a predetermined dopant juxtaposed between said first and second semiconductor layers, and source, gate and drain electrodes fabricated from a metallic conducting material, characterized in that a plurality of delta-doped monolayers are interposed between said source and drain electrodes and said second semiconductor layer, said plurality of delta-doped monolayers being separated from each other and from the source and drain electrodes by layers of semiconductor material each one of which has a thickness equal to or less than the tunneling width of electrons in said semiconductor material, and said gate electrode is positioned in a channel that is cut through said plurality of delta-doped monolayers such that the gate electrode is in direct contact with said second semiconductor layer.
Claim 3
Dependent Claim
19 words
A field-effect transistor as defined in claim 1 wherein said semiconductor material is GaAs and said dopant is silicon.
Claim 4
Dependent Claim
118 words
A field-effect transistor comprising a semiconductor substrate, first and second semiconductor layers grown on said substrate, at least one delta-doped monolayer having a predetermined dopant juxtaposed between said first and second semiconductor layers, a channel etched in said second layer thereby defining ridges of semiconductor material on each of its sides, a gate electrode positioned in said channel, a plurality of delta-doped monolayers fabricated on the ridges on each side of said channel, and interleaved with layers of semiconductor material having a predetermined thickness, said predetermined thickness being equal to or less than the tunneling width of electrons in said semiconductor material, and metal electrodes positioned on said plurality of delta-doped layers on each side of said channel.
Claim 5
Dependent Claim
118 words
A field-effect transistor comprising a semiconductor substrate, first and second semiconductor layers grown on said substrate, at least one delta-doped monolayer having a predetermined dopant juxtaposed between said first and second semiconductor layers, a channel etched in said second layer thereby defining ridges of semiconductor material on each of its sides, a gate electrode positioned in said channel, a plurality of delta-doped monolayers fabricated on the ridges on each side of said channel, and interleaved with layers of semiconductor material having a predetermined thickness, said predetermined thickness being equal to or less than the tunneling width of electrons in said semiconductor material, and metal electrodes positioned on said plurality of delta-doped layers on each side of said channel.
Claim 6
Dependent Claim
19 words
A field-effect transistor as defined in claim 3 wherein said semiconductor material is GaAs and said dopant is silicon.
References Cited (Backward Citations)
US4205329A
Cited
US4583110A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1991-10-25 | 1992-04-25 | 1992-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-25 | 1996-04-25 | 1996-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-25 | 2000-04-25 | 2000-10-25 | $7700.00 | Window Closed / Lapsed |