US4783427A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for fabricating quantum-well devices
Assignee: Texas Instruments Inc
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Filing: 1986-02-18
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Granted: 1988-11-08
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Expires: 2006-02-18
Abstract
Abstract The present invention teaches a process for fabrication of quantum-well devices, in which the quantum-wells are configured as small islands of GaAs in an AlGaAs matrix. Typically these islands are roughly cubic, with dimensions of about 100 Angstroms per side. To fabricate these, an n- on n+ epitaxial GaAs structure is grown, and then is etched to an e-beam defined patterned twice, and AlGaAs is epitaxially regrown each time. This defines the quantum wells of GaAs in the AlGaAs matrix, and output contacts are then easily formed.
Inventors
- 👤 Mark A. Reed
- 👤 Robert T. Bate
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:38
CPC Classifications
B; B82; B82Y; B82Y10/00; H; H10; H10D; H10D48/00; H10D48/30; H10D48/32; H10D48/36; H10D48/362; H10D62/00; H10D62/80; H10D62/81; H10D62/815; H10D62/8181; H10D84/00; H10D84/01; H10D84/02; H10D84/05; Y; Y10; Y10S; Y10S438/00; Y10S438/962; Y10S438/979
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
160 words
A process for fabricating quantum-well devices, comprising the steps of: (a) providing a substrate; (b) providing M epitaxial layers of semiconductor materials on said substrate, at least one of said layers of quantum-well thickness; (c) anisotropically etching first trenches in a first pattern through the top N of said layers but not through the bottom M-N of said layers; (d) epitaxially growing a layer of a wide bandgap semiconductor material with a bandgap wider than those of all of the semiconductor materials of said M layers, said growing to substantially fill said first trenches; (e) anisotropically etching second trenches in a second pattern through both said M layers and said wide bandgap layer, said first and second trenches jointly define a plurality of quantum wells; (f) epitaxially growing a second layer of said wide bandgap material to substantially fill said second trenches; and (g) forming contacts to configure desired circuit functions from said quantum wells to yield said quantum-well devices.
Claim 2
Dependent Claim
160 words
A process for fabricating quantum-well devices, comprising the steps of: (a) providing a substrate; (b) providing M epitaxial layers of semiconductor materials on said substrate, at least one of said layers of quantum-well thickness; (c) anisotropically etching first trenches in a first pattern through the top N of said layers but not through the bottom M-N of said layers; (d) epitaxially growing a layer of a wide bandgap semiconductor material with a bandgap wider than those of all of the semiconductor materials of said M layers, said growing to substantially fill said first trenches; (e) anisotropically etching second trenches in a second pattern through both said M layers and said wide bandgap layer, said first and second trenches jointly define a plurality of quantum wells; (f) epitaxially growing a second layer of said wide bandgap material to substantially fill said second trenches; and (g) forming contacts to configure desired circuit functions from said quantum wells to yield said quantum-well devices.
Claim 3
Dependent Claim
77 words
The process of claim 1, further comprising the steps of: (h) providing an insulating layer over the first tier of devices formed by steps (a)-(g) of claim 1; (i) repeating steps (a)-(g) of claim 1 to form a second tier of devices on said insulating layer over the first tier of devices; and (j) forming vias and filling them with conductive material to interconnect the devices of the second tier to the devices of the first tier.
Claim 4
Dependent Claim
23 words
The process of claim 2, further comprising the steps of: (a) repeating steps (h)-(j) P times to yield a (P+2)-tiered stack of devices.
Claim 5
Dependent Claim
14 words
The process of claim 1, wherein: (a) M equals three and N equals two.
Claim 6
Dependent Claim
14 words
The process of claim 2, wherein: (a) M equals three and N equals two.
Claim 7
Dependent Claim
14 words
The process of claim 3, wherein: (a) M equals three and N equals two.
Claim 8
Dependent Claim
24 words
The process of claim 1, wherein: (a) said M layers of semiconductor materials are all of the same semiconductor material although with different dopings.
Claim 9
Dependent Claim
24 words
The process of claim 2, wherein: (a) said M layers of semiconductor materials are all of the same semiconductor material although with different dopings.
Claim 10
Dependent Claim
24 words
The process of claim 3, wherein: (a) said M layers of semiconductor materials are all of the same semiconductor material although with different dopings.
Claim 11
Dependent Claim
29 words
The process of claim 1, wherein: (a) said M semiconductor materials and said wide band gap semiconductor material are each Al x Ga 1-x As with possibly different xs.
Claim 12
Dependent Claim
29 words
The process of claim 2, wherein: (a) said M semiconductor materials and said wide band gap semiconductor material are each Al x Ga 1-x As with possibly different xs.
Claim 13
Dependent Claim
29 words
The process of claim 3, wherein: (a) said M semiconductor materials and said wide band gap semiconductor material are each Al x Ga 1-x As with possibly different xs.
Claim 14
Dependent Claim
80 words
The process of claim 1, further comprising the steps of: (h) providing an insulating layer over the devices formed by steps (a)-(g) of claim 1; (i) repeating steps (a)-(g) of claim 1 but with different M or N to form a second tier of devices on said insulating layer over said devices formed steps (a)-(g); and (j) forming vias and filling them with conductive material to interconnect the devices of the second tier to the device of the first tier.
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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) | 1991-11-08 | 1992-05-09 | 1992-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-08 | 1996-05-09 | 1996-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-08 | 2000-05-09 | 2000-11-08 | $7700.00 | Window Closed / Lapsed |