US3636618A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ohmic contact for semiconductor devices
Assignee: Monsanto Co
•
Filing: 1970-03-23
•
Granted: 1972-01-25
•
Expires: 1990-03-23
Abstract
Abstract The disclosure herein relates to a method for forming ohmic contacts to the backside of solid-state semiconductor devices comprising a sequential deposition and alloying of a multilayered structure comprising, respectively, tin, gold, nickel and gold alloyed to the semiconductor body, which is then mounted on a gold-plated metal base with a gold epoxy preform. Other suitable base and preform materials are also disclosed.
Inventors
- 👤 Arno Henry Herzog
- 👤 James F Caldwell
- 👤 John George Schmidt
- 👤 Enghua Lim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:58
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/83; H10H20/832; H10W; H10W20/00; H10W20/40; H10H20/81; H10H20/822; H10H20/824
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
27 words
Method according to claim 1 wherein the semiconductor component of said semiconductor device comprises N-type GaAs1 xPx, wherein x is a number from 0 to 1 inclusive.
Claim 2
Dependent Claim
18 words
Method according to claim 2 wherein said GaAs1*xPx is in epitaxial connection with a substrate of N-type GaAs.
Claim 3
Dependent Claim
19 words
Method according to claim 1 wherein said preform is a gold/epoxy mixture and said base is gold plated Kovar.
Claim 4
Dependent Claim
25 words
Method according to claim 1 wherein said preform is a gold/germanium alloy and said base is alumina with a screen printed and fired gold/palladium alloy.
Claim 5
Dependent Claim
175 words
Method of forming an ohmic contact to a semiconductor device which comprises: a. providing a semiconductor device having a region of N-type conductivity; b. applying a layer of tin to an N-type surface of said semiconductor device; c. applying a layer of gold to said layer of tin; d. heating the combined structure formed in steps (a)-(c) at temperatures and for a time sufficient to alloy the metals in the layers of steps (b) and (c) with said region of N-type conductivity and form a region of N conductivity type therein; e. applying a layer of nickel to said region of N conductivity type; f. applying a layer of gold to said layer of nickel; g. heating the structure formed through steps (d)-(f) at temperatures and for a time sufficient to alloy the metals in the layers of steps (e) and (f) with said region of N conductivity type and form a layer rich in nickel and; h. mounting the structure formed in step (g) on a suitable base by means of a suitable preform.
Claim 6
Dependent Claim
27 words
Method according to claim 6 wherein the semiconductor component of said semiconductor device comprises N-type GaAs1 xPx, wherein x is a number from 0 to 1 inclusive.
Claim 7
Dependent Claim
19 words
Method according to claim 7 wherein said GaAs1 xPx is in epitaxial connection with a substrate of N-type GaAs.
Claim 8
Dependent Claim
19 words
Method according to claim 6 wherein said preform is a gold/epoxy mixture and said base is gold plated Kovar.
Claim 9
Dependent Claim
25 words
Method according to claim 6 wherein said preform is a gold/germanium alloy and said base is alumina with a screen printed and fired gold/palladium alloy.
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) | 1975-01-24 | 1975-07-26 | 1976-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-24 | 1979-07-26 | 1980-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-24 | 1983-07-26 | 1984-01-25 | $7700.00 | Window Closed / Lapsed |