US4645707A
Expired / Lapsed
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Semiconductor devices
Assignee: The General Electric Company PLC
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Filing: 1985-11-19
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Granted: 1987-02-24
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Expires: 2005-11-19
Abstract
Abstract A semiconductor device incorporating two superlattices in the GaAs/AlGaAs system separated by a relatively thick layer of GaAlAs is described. The device displays negative differential conductance.
Inventors
- 👤 Richard A. Davies
- 👤 Michael J. Kelly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:02
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/80; H10D62/81; H10D62/815; H10D62/8161; H10D62/8162; H10D62/8164; H10D8/00; H10D8/70; Y; Y10; Y10S; Y10S428/00; Y10S428/901; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/2495
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
134 words
A semiconductor device exhibiting negative differential conductance, the device comprising two superlattices each comprising alternating layers of two different semiconductor materials such that there is a misalignment of energy band edges between each pair of adjacent layers with the layers of one of the materials constituting potential barriers to charge carriers passing through each superlattices, said superlattices being coupled to each other by a barrier layer of semiconductor material forming respective heterojunctions with the adjacent layers of the superlattices, said barrier layer having a lower transmission coefficient for said charge carriers than said layers of said one material, said superlattices defining the allowed energy levels of said charge carriers at either side of said barrier layer, and the value of a potential applied across said barrier layer determining the current-voltage characteristics of the device.
Claim 2
Dependent Claim
134 words
A semiconductor device exhibiting negative differential conductance, the device comprising two superlattices each comprising alternating layers of two different semiconductor materials such that there is a misalignment of energy band edges between each pair of adjacent layers with the layers of one of the materials constituting potential barriers to charge carriers passing through each superlattices, said superlattices being coupled to each other by a barrier layer of semiconductor material forming respective heterojunctions with the adjacent layers of the superlattices, said barrier layer having a lower transmission coefficient for said charge carriers than said layers of said one material, said superlattices defining the allowed energy levels of said charge carriers at either side of said barrier layer, and the value of a potential applied across said barrier layer determining the current-voltage characteristics of the device.
Claim 3
Dependent Claim
33 words
A device according to claim 1 in which said one material and the material of said barrier layer is Al x Ga 1-x As, and the other material in each superlattice is GaAs.
Claim 4
Dependent Claim
11 words
A device according to claim 2 in which χ is 0.45.
Claim 5
Dependent Claim
28 words
A device according to claim 2 in which said layers of GaAs are doped with silicon to put the Fermi level in the first miniband for each superlattice.
Claim 6
Dependent Claim
29 words
A device according to claim 4 in which said layers of GaAs are doped in a region spaced away from the adjacent layers of Al x Ga 1-x As.
Claim 7
Dependent Claim
24 words
A device according to claim 1 in which said barrier layer is at least twice as thick as said layers of said one material.
Claim 8
Dependent Claim
18 words
A device according to claim 1 in which each of said superlattices is of at least three periods.
Claim 9
Dependent Claim
30 words
A device according to claim 1 in which the width of the first miniband for each of said superlattices is less than the optic phonon energy for said one material.
Claim 10
Dependent Claim
11 words
A device according to claim 2 in which χ is 0.25.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-23 | 1990-08-25 | 1991-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-23 | 1994-08-25 | 1995-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-23 | 1998-08-25 | 1999-02-24 | $7700.00 | Window Closed / Lapsed |