US4026741A
Expired / Lapsed
US
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Technique for preparation of stoichiometric III-V compound semiconductor surfaces
Assignee: AT&T Inc
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Filing: 1976-06-16
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Granted: 1977-05-31
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Expires: 1996-06-16
Abstract
Abstract A technique for preparing stoichiometric group III-V compound semiconductor surfaces involves a repetitive anodizing and etching sequence in an aqueous solution of appropriate pH and a basic solution, respectively. Surfaces treated in the described manner evidence a correct surface stoichiometry and minimum carbon contamination.
Inventors
- 👤 Chuan Chung Chang
- 👤 Paul H. Citrin
- 👤 Bertram Schwartz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:48
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6306; H10P14/6312; C; C25; C25D; C25D11/00; C25D11/02; C25D11/32; H10P50/00; H10P50/60; H10P50/61; H10P50/617; H10P50/64; H10P50/642; H10P50/646; H10P14/6324; Y; Y10; Y10S; Y10S438/00; Y10S438/971
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
137 words
Technique for preparing stoichiometric Group III-V compound semiconductor surfaces which comprises the steps of (a) anodizing a group III-V compound semiconductor in an aqueous electrolyte having a pH within the range of 1.5-8 at an anodizing voltage within the range of 50-175 volts for a time period sufficient to yield an oxide film of approximately 1000 Angstroms, (b) etching off the oxide film with a basic etchant, having a pH from 8-13.5, (c) reanodizing the resultant assembly at an anodizing voltage within the range of 5-10 volts for a time period sufficient to yield a second oxide film ranging up to 200 Angstroms, and (d) stripping the second oxide film with a basic etchant having a pH from 8-13.5 by immersion in the etchant for a time period sufficient to remove only the grown second oxide film.
Claim 2
Dependent Claim
137 words
Technique for preparing stoichiometric Group III-V compound semiconductor surfaces which comprises the steps of (a) anodizing a group III-V compound semiconductor in an aqueous electrolyte having a pH within the range of 1.5-8 at an anodizing voltage within the range of 50-175 volts for a time period sufficient to yield an oxide film of approximately 1000 Angstroms, (b) etching off the oxide film with a basic etchant, having a pH from 8-13.5, (c) reanodizing the resultant assembly at an anodizing voltage within the range of 5-10 volts for a time period sufficient to yield a second oxide film ranging up to 200 Angstroms, and (d) stripping the second oxide film with a basic etchant having a pH from 8-13.5 by immersion in the etchant for a time period sufficient to remove only the grown second oxide film.
Claim 3
Dependent Claim
13 words
Technique in accordance with claim 1 wherein the aqueous electrolyte is phosphoric acid.
Claim 4
Dependent Claim
14 words
Technique in accordance with claim 1 wherein the aqueous electrolyte is ammonium acid phosphide.
Claim 5
Dependent Claim
12 words
Technique in accordance with claim 1 wherein the etchant is ammonium hydroxide.
Claim 6
Dependent Claim
12 words
Technique in accordance with claim 2 wherein the etchant is ammonium hydroxide.
Claim 7
Dependent Claim
13 words
Technique in accordance with claim 5 wherein the compound semiconductor is gallium phosphide.
References Cited (Backward Citations)
US3798139A
Cited
US3898141A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-30 | 1980-11-29 | 1981-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-30 | 1984-11-29 | 1985-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-30 | 1988-11-29 | 1989-05-31 | $7700.00 | Window Closed / Lapsed |