US4297783A
Expired / Lapsed
US
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Method of fabricating GaAs devices utilizing a semi-insulating layer of AlGaAs in combination with an overlying masking layer
Assignee: AT&T Inc
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Filing: 1980-04-21
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Granted: 1981-11-03
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Expires: 2000-04-21
Abstract
Abstract Surface recombination current in GaAs devices is reduced by means of a semi-insulating, oxygen, iron or chromium doped monocrystalline layer of AlGaAs grown by MBE. The AlGaAs layer is grown on a GaAs body and is then masked. Diffusion of suitable impurities through a window in the mask converts the exposed portions of the AlGaAs layer to low resistivity and modifies the conductivity of the underlying zone of the GaAs body. The peripheral portions of the AlGaAs layer, however, remain semi-insulating and are effective to reduce the surface recombination velocity - diffusion length product by more than an order of magnitude.
Inventors
- 👤 Horace C. Casey, Jr.
- 👤 Alfred Y. Cho
- 👤 Philip W. Foy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:06
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/20; H10P14/22; H10D; H10D62/00; H10D62/10; H10D62/102; H10D62/112; H10P14/29; H10P14/2901; H10P14/2907; H10P14/2911; H10P14/32; H10P14/3202; H10P14/3214; H10P14/3221; H10P14/34; H10P14/3402; H10P14/3414; H10P14/3421; H10P14/3438; H10P14/3441; H10P14/3446; H10P14/60; H10P76/00; H10P76/40; H10P76/405
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
155 words
A method of fabricating a GaAs device having reduced surface recombination current comprising the steps of: (a) growing by molecular beam epitaxy a monocrystalline, semi-insulating layer (16) of AlGaAs on a major surface of a monocrystalline body of GaAs (10), CHARACTERIZED BY (b) forming a masking layer (18) on said AlGaAs layer, (c) opening a window in said masking layer so as to expose the underlying portion (16.2) of said AlGaAs layer but leave adjacent peripheral portions of said AlGaAs layer covered by said masking layer, (d) introducing impurities through said window so as to modify the conductivity of the underlying zone (26) of said GaAs body and to convert said underlying portion (16.2) of said AlGaAs layer from semi-insulating to low resistivity while leaving said adjacent peripheral portions (16.1) semi-insulating, and (e) forming electrical contacts (20,24) to said underlying portion (16.2) of said AlGaAs layer and to an opposite major surface of said body.
Claim 2
Independent Claim
155 words
A method of fabricating a GaAs device having reduced surface recombination current comprising the steps of: (a) growing by molecular beam epitaxy a monocrystalline, semi-insulating layer (16) of AlGaAs on a major surface of a monocrystalline body of GaAs (10), CHARACTERIZED BY (b) forming a masking layer (18) on said AlGaAs layer, (c) opening a window in said masking layer so as to expose the underlying portion (16.2) of said AlGaAs layer but leave adjacent peripheral portions of said AlGaAs layer covered by said masking layer, (d) introducing impurities through said window so as to modify the conductivity of the underlying zone (26) of said GaAs body and to convert said underlying portion (16.2) of said AlGaAs layer from semi-insulating to low resistivity while leaving said adjacent peripheral portions (16.1) semi-insulating, and (e) forming electrical contacts (20,24) to said underlying portion (16.2) of said AlGaAs layer and to an opposite major surface of said body.
Claim 3
Dependent Claim
36 words
The method of claim 1 wherein step (d) is effective to reverse the conductivity type of said zone with respect to adjacent portions of said body, thereby forming a p-n junction (28) at the boundary therebetween.
Claim 4
Dependent Claim
27 words
The method of claim 2 wherein said GaAs body is n-type, and in step (d) Zn impurities are diffused through said window to form said p-n junction.
Claim 5
Independent Claim
56 words
The method of claims 2 or 3 wherein prior to step (a), said body is formed by the additional step of growing an epitaxial GaAs layer (14) of one conductivity type on a GaAs substrate (12) of the same conductivity type, and step (d) is effective to form said p-n junction in said epitaxial layer (14).
Claim 6
Dependent Claim
33 words
The method of claim 1 wherein step (d) is effective to increase the conductivity of said zone with respect to adjacent portions of said body without reversing the conductivity type of said zone.
Claim 7
Independent Claim
22 words
The method of claims 2 or 5 wherein in step (b) a silicon nitride masking layer is formed on said AlGaAs layer.
Claim 8
Dependent Claim
39 words
The method of claim 1 wherein in step (a) said AlGaAs layer is grown to have a resistivity in the range of about 10 8 to 10 12 Ω-cm and a thickness sufficient to prevent any appreciable tunneling therethrough.
Claim 9
Dependent Claim
24 words
The method of claim 1 wherein said AlGaAs layer is doped with an impurity selected from the group consisting of oxygen, iron, and chromium.
Claim 10
Independent Claim
16 words
A method of fabricating a GaAs device having reduced surface recombination current comprising the steps of
Claim 11
Independent Claim
16 words
A method of fabricating a GaAs device having reduced surface recombination current comprising the steps of
Claim 12
Dependent Claim
200 words
(a) epitaxially growing a GaAs layer of one conductivity type on a GaAs substrate of the same conductivity type, (b) growing by molecular beam epitaxy a monocrystalline, semi-insulating layer of oxygen-doped Al x Ga 1-x As (0.4≲×≦1) on a major surface of said epitaxial layer so that said Al x Ga 1-x As layer has a resistivity in the range of about 10 8 to 10 12 Ω-cm and a thickness sufficient to prevent appreciable tunneling therethrough, CHARACTERIZED BY (c) forming a diffusion masking layer on said Al x Ga 1-x As layer, (d) opening a window in said masking layer so as to expose the underlying portion of said AlGaAs layer but leave adjacent peripheral portions thereof covered by said masking layer, (e) diffusing impurities through said window so as to reverse the conductivity of the underlying zone of said epitaxial layer and to convert said underlying portion of said Al x Ga 1-x As layer from semi-insulating to a low resistivity of the order of 10 -1 to 10 -3 Ω-cm while leaving said peripheral portions semi-insulating, and (f) forming electrical contacts to said underlying portion of said Al x Ga 1-x As layer and to said substrate.
Claim 13
Dependent Claim
200 words
(a) epitaxially growing a GaAs layer of one conductivity type on a GaAs substrate of the same conductivity type, (b) growing by molecular beam epitaxy a monocrystalline, semi-insulating layer of oxygen-doped Al x Ga 1-x As (0.4≲×≦1) on a major surface of said epitaxial layer so that said Al x Ga 1-x As layer has a resistivity in the range of about 10 8 to 10 12 Ω-cm and a thickness sufficient to prevent appreciable tunneling therethrough, CHARACTERIZED BY (c) forming a diffusion masking layer on said Al x Ga 1-x As layer, (d) opening a window in said masking layer so as to expose the underlying portion of said AlGaAs layer but leave adjacent peripheral portions thereof covered by said masking layer, (e) diffusing impurities through said window so as to reverse the conductivity of the underlying zone of said epitaxial layer and to convert said underlying portion of said Al x Ga 1-x As layer from semi-insulating to a low resistivity of the order of 10 -1 to 10 -3 Ω-cm while leaving said peripheral portions semi-insulating, and (f) forming electrical contacts to said underlying portion of said Al x Ga 1-x As layer and to said substrate.
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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) | 1984-11-02 | 1985-05-04 | 1985-11-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-02 | 1989-05-04 | 1989-11-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-02 | 1993-05-04 | 1993-11-03 | $7700.00 | Window Closed / Lapsed |