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US3947304A
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Etching of group III-V semiconductors
Assignee: AT&T Inc
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Filing: 1972-08-15
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Granted: 1976-03-30
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Expires: 1992-08-15
Abstract
Abstract Group III-V compound semiconductor devices with attached gold conductor areas are etched using a basic ferricyanide etchant. The etchant is an aqueous solution containing ferricyanide ions in a concentration from 0.8 molar to 1.2 molar and sodium or potassium hydroxide in a concentration from 0.3 molar to 1.5 molar. This etchant rapidly removes the semiconductor material leaving smooth surfaces, while leaving the gold conductors and areas protected by oxide layers essentially intact. The use of titanium layers as etching masks, deposited for example by evaporating or sputtering through a removable mask, is also disclosed.
Inventors
- 👤 Lillian Rankel Plauger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:58
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/60; H10P50/64; H10P50/642; H10P50/646; H10W; H10W72/00; H10W72/60
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
123 words
Method for the production of a semiconductor device comprising etching a body consisting of at least a semiconductor body and a first metallic body affixed thereto, in which at least 99 percent by weight of the semiconductor body consists of a Group III-V compound semiconductor and in which the first metallic body includes gold, by contacting at least a portion of the semiconductor body and at least a portion of the gold with an etchant characterized in that the etchant consists essentially of an aqueous solution containing ferricyanide ions in a concentration from 0.8 molar to 1.2 molar and at least one hydroxide of the group consisting of sodium hydroxide and potassium hydroxide in a total concentration from 0.3 molar to 1.5 molar.
Claim 2
Dependent Claim
123 words
Method for the production of a semiconductor device comprising etching a body consisting of at least a semiconductor body and a first metallic body affixed thereto, in which at least 99 percent by weight of the semiconductor body consists of a Group III-V compound semiconductor and in which the first metallic body includes gold, by contacting at least a portion of the semiconductor body and at least a portion of the gold with an etchant characterized in that the etchant consists essentially of an aqueous solution containing ferricyanide ions in a concentration from 0.8 molar to 1.2 molar and at least one hydroxide of the group consisting of sodium hydroxide and potassium hydroxide in a total concentration from 0.3 molar to 1.5 molar.
Claim 3
Dependent Claim
38 words
Method of claim 1 in which the ferricyanide ions are derived from a ferricyanide compound which compound is at least one member selected from the group consisting of K 3 Fe(CN) 6 and Na 3 Fe(CN) 6 .
Claim 4
Dependent Claim
15 words
Method of claim 2 in which the ferricyanide compound is K 3 Fe(CN) 6 .
Claim 5
Dependent Claim
24 words
Method of claim 2 in which the Group III-V compound semiconductor is at least one member of the group consisting of GaP and GaAs.
Claim 6
Dependent Claim
17 words
Method of claim 4 in which the etching takes place at a temperature from 60°C to 95°C.
Claim 7
Dependent Claim
17 words
Method of claim 5 in which the etching takes place at a temperature from 75°C to 85°C.
Claim 8
Dependent Claim
34 words
Method of claim 4 in which the ferricyanide ions are present in a concentration from 0.9 molar to 1.2 molar and the hydroxide is present in a concentration from 0.4 molar to 0.7 molar.
Claim 9
Dependent Claim
33 words
Method of claim 1 in which a second metallic body is affixed to the semiconductor body, which second metallic body includes a layer of titanium metal between 500 Angstroms and 5000 Angstroms thick.
Claim 10
Dependent Claim
18 words
Method of claim 8 in which the second metallic body is from 1000 Angstroms to 3000 Angstroms thick.
Claim 11
Dependent Claim
20 words
Method of claim 8 in which the second metallic body is deposited onto the semiconductor portion through a removable mask.
Claim 12
Dependent Claim
14 words
Method of claim 8 in which the second metallic body is deposited by sputtering.
Claim 13
Dependent Claim
99 words
Method for the production of a semiconductor device comprising etching a body consisting of at least a semiconductor body in which at least 99 percent by weight of the semiconductor body consists of a Group III-V compound semiconductor, by contacting at least a portion of the semiconductor body with an etchant characterized in that the etchant consists essentially of an aqueous solution containing ferricyanide ions in a concentration from 0.8 molar to 1.2 molar and at least one hydroxide of the group consisting of sodium hydroxide and potassium hydroxide in a total concentration from 0.3 molar to 1.5 molar.
Claim 14
Dependent Claim
99 words
Method for the production of a semiconductor device comprising etching a body consisting of at least a semiconductor body in which at least 99 percent by weight of the semiconductor body consists of a Group III-V compound semiconductor, by contacting at least a portion of the semiconductor body with an etchant characterized in that the etchant consists essentially of an aqueous solution containing ferricyanide ions in a concentration from 0.8 molar to 1.2 molar and at least one hydroxide of the group consisting of sodium hydroxide and potassium hydroxide in a total concentration from 0.3 molar to 1.5 molar.
References Cited (Backward Citations)
US3674580A
Cited
US3716429A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-03-30 | 1979-09-29 | 1980-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-30 | 1983-09-29 | 1984-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-30 | 1987-09-29 | 1988-03-30 | $7700.00 | Window Closed / Lapsed |