US4399004A
Expired / Lapsed
US
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Photoelectrochemical gold plating process
Assignee: AT&T Inc
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Filing: 1981-06-11
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Granted: 1983-08-16
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Expires: 2001-06-11
Abstract
Abstract A process is described for plating gold on metal surfaces electrically attached to a compound semiconductor. The procedure is particularly valuable where gold is to be in small holes or crevices in semiconductor structure since electroplating on the semiconductor surface is avoided. The process is useful for providing low inductance electrical connection to various parts of semiconductor devices such as to the source in gallium arsenide field-effect transistors.
Inventors
- 👤 Reginald R. Buckley
- 👤 Lucian A. D'Asaro
- 👤 Paul A. Kohl
- 👤 Frederick W. Ostermayer, Jr.
- 👤 Catherine Wolowodiuk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 01:31
CPC Classifications
C; C25; C25D; C25D3/00; C25D3/02; C25D3/48; H; H10; H10P; H10P95/00; H10P14/00; H10P14/40; H10P14/46
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
119 words
A process for fabricating devices comprising at least one n-type or intrinsic III-V compound semiconductor material comprising at least one step in which gold is plated on a metallic surface electrically connected to the III-V compound semiconductor by a oxidation-reduction reaction in an electrolytic solution characterized in that a. the oxidation is carried out by illuminating the III-V compound semiconductor with light with photon energy at least as great as the band gap of the compound semiconductor so as to create holes that permit oxidation of the semiconductor b. the electrolytic solution comprises a source of gold which on reduction yields metallic gold, and c. the source of gold is reduced on the metallic surface to form metallic gold.
Claim 2
Dependent Claim
119 words
A process for fabricating devices comprising at least one n-type or intrinsic III-V compound semiconductor material comprising at least one step in which gold is plated on a metallic surface electrically connected to the III-V compound semiconductor by a oxidation-reduction reaction in an electrolytic solution characterized in that a. the oxidation is carried out by illuminating the III-V compound semiconductor with light with photon energy at least as great as the band gap of the compound semiconductor so as to create holes that permit oxidation of the semiconductor b. the electrolytic solution comprises a source of gold which on reduction yields metallic gold, and c. the source of gold is reduced on the metallic surface to form metallic gold.
Claim 3
Dependent Claim
32 words
The process of claim 1 in which the III-V compound semiconductor is selected from the group consisting of GaP, GaAs, AlAs, AlP, AlSb, InP, InSb, InAs, GaInAs, GaInP, GaInAsP, GaAlP and GaAlAs.
Claim 4
Dependent Claim
13 words
The process of claim 1 in which the III-V compound semiconductor is undoped.
Claim 5
Dependent Claim
13 words
The process of claim 1 in which the III-V semiconductor is semi-insulating GaAs.
Claim 6
Dependent Claim
29 words
The process of claim 4 in which the GaAs is made semi-insulating by doping with chromium in the concentration range from 10 15 to 10 17 Cr/cm 3 .
Claim 7
Dependent Claim
12 words
The process of claim 2 in which the compound semiconductor is n-type.
Claim 8
Dependent Claim
33 words
The process of claim 6 in which the compound semiconductor is made n-type by doping with at least one element selected from the group consisting of Si, Ge, Sn, S, Se and Te.
Claim 9
Dependent Claim
16 words
The process of claim 1 in which the source of gold is gold cyanide complex ion.
Claim 10
Dependent Claim
15 words
The process of claim 8 in which the source of gold is potassium gold cyanide.
Claim 11
Dependent Claim
19 words
The process of claim 9 in which the concentration of potassium gold cyanide is between 0.01 to 0.2 Molar.
Claim 12
Dependent Claim
15 words
The process of claim 1 in which the electrolytic solution has pH less than 4.
Claim 13
Dependent Claim
15 words
The process of claim 1 in which the electrolytic solution has pH greater than 8.
Claim 14
Dependent Claim
13 words
The process of claim 1 in which the electrolytic solution contains chloride ion.
Claim 15
Dependent Claim
12 words
The process of claim 1 in which the electrolytic solution is buffered.
Claim 16
Dependent Claim
13 words
The process of claim 1 in which the electrolytic solution comprises conducting salts.
Claim 17
Dependent Claim
24 words
The process of claim 1 in which the electrolytic solution has a temperature between 40 and 75 degrees C. during the gold plating procedure.
Claim 18
Dependent Claim
48 words
The process of claim 1 in which the compound semiconductor is gallium arsenide, the gold is plated in a via hole and onto the source pad and the electrolytic solution comprises water and 1-40 gm/l KAu(CN) 2 , 100 gm/l KH 2 PO 4 and 28 gm/l KOH.
Claim 19
Dependent Claim
55 words
The process of claim 1 in which prior to plating the semiconductor is cleaned by a procedure comprising the steps of: a. immersing the compound semiconductor in a cyanide solution; and b. subsequently immersing the compound semiconductor in a solution consisting essentially of three parts sulfuric acid, one part peroxide solution and one part water.
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) | 1986-08-15 | 1987-02-14 | 1987-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-15 | 1991-02-14 | 1991-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-15 | 1995-02-14 | 1995-08-16 | $7700.00 | Window Closed / Lapsed |