US3731372A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming a low-ohmic contact to a semiconductor device
Assignee: TDK Micronas GmbH
•
Filing: 1971-03-15
•
Granted: 1973-05-08
•
Expires: 1991-03-15
Abstract
Abstract A low ohmic contact for a semiconductor device is made to a pconductivity type region by diffusing some n conductivity type phosphorous into said region before the contact metal is applied to said region. The amount of phosphorous is kept at a minimum to prevent the formation of an unwanted pn junction.
Inventors
- 👤 W Kraft
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 07:49
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/20; H10D; H10D99/00; H10P; H10P95/00; Y; Y10; Y10S; Y10S148/00; Y10S148/018; Y10S148/02; Y10S148/037; Y10S148/049; Y10S148/085
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
23 words
A method according to claim 1, wherein said surface zone has a smaller doping concentration than the doping concentration of said contact zone.
Claim 2
Dependent Claim
40 words
A method according to claim 1, further comprising an NPN planar transistor formed within said semiconductor body wherein said first zone is the base of said transistor and said contact zone has a higher doping concentration than said base zone.
Claim 3
Dependent Claim
46 words
A method according to claim 3, further comprising a p-conductivity substrate beneath said body, and an isolating zone surrounding said transistor and extending to said substrate, wherein said isolating zone and contact zone are formed simultaneously during a diffusion step using boron as the doping material.
Claim 4
Dependent Claim
18 words
A method according to claim 3, wherein said surface zone is diffused in simultaneously with said emitter zone.
Claim 5
Dependent Claim
16 words
A method according to claim 1, wherein said surface zone is diffused in an oxygen-free atmosphere.
Claim 6
Dependent Claim
28 words
A method according to claim 6, wherein said surface zone diffusion is carried out in an atmosphere containing an inert carrier gas of nitrogen or argon, and phosphine.
Claim 7
Dependent Claim
19 words
A method according to claim 1, wherein said contact zone is diffused into a highly doped n-type intermediate layer.
Claim 8
Dependent Claim
20 words
A method according to claim 1, wherein said contact metal is selected from a group consisting of aluminum or nickel.
References Cited (Backward Citations)
US3479736A
Cited
US3474309A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-07 | 1976-11-06 | 1977-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-07 | 1980-11-06 | 1981-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-07 | 1984-11-06 | 1985-05-08 | $7700.00 | Window Closed / Lapsed |