US3604986A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High frequency transistors with shallow emitters
Assignee: AT&T Inc
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Filing: 1970-03-17
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Granted: 1971-09-14
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Expires: 1990-03-17
Abstract
Abstract It has been recognized that a Pt-Si contact forms without the usual concentration of minority carrier recombination sites. Thus, as applied to emitter regions, the contact appears to be an extension of the semiconductor. This allows the emitter region to be very shallow leading to better control of the base width. Methods for fabrication taking advantage of ion implantation techniques for forming very shallow, sharp emitter profiles are also described.
Inventors
- 👤 Martin Paul Lepselter
- 👤 Alfred Urquhart Macrae
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:36
CPC Classifications
H; H10; H10P; H10P95/00; H10D; H10D99/00; H10P32/00; H10P32/10; H10P32/14; H10P32/1408; H10P32/1414; H10P32/17; H10P32/171
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
30 words
The transistor of claim 1 in which the metal component of the silicide is selected from the group consisting of nickel, titanium, zirconium, hafnium, and the six platinum group metals.
Claim 2
Independent Claim
94 words
A method for making a high frequency silicon transistor comprising forming within a silicon substrate collector, base and emitter regions, the base region having a width of less than 1, 000 A. and the emitter region having a depth of less than 1,000 A. and forming electrical contacts with each region, forming the emitter contact including depositing on the surface of the emitter region a metal layer selected from the group consisting of nickel, titanium, zirconium, hafnium, and the six platinum group metals and heating the metal layer to form a metal silicide contact.
Claim 3
Dependent Claim
47 words
A method according to claim 3 in which forming the emitter region includes codepositing of the silicon substrate the said metal along with the impurity for forming the emitter region and heating the codeposited layer to diffuse the emitter region while simultaneously forming the metal silicide contact.
Claim 4
Dependent Claim
18 words
The method of claim 4 in which the metal is platinum codeposited with a small amount of arsenic.
Claim 5
Dependent Claim
40 words
The method of claim 3 in which the impurity forming the emitter region is deposited in the surface of the substrate prior to deposition of the metal layer so that diffusion is enhanced during formation of the metal silicide contact.
Claim 6
Dependent Claim
25 words
The method of claim 5 in which the codeposited layer is heated to approximately 700* C. to diffuse the emitter and form the metal silicide.
Claim 7
Dependent Claim
31 words
A method according to claim 3 in which forming the emitter includes diffusing a conductivity type determining impurity through the said metal layer prior to the formation of the metal silicide.
Claim 8
Dependent Claim
31 words
The method of claim 3 in which forming the emitter region includes implantations of the conductivity-type determining impurity therein through the metal layer prior to the formation of the metal silicide.
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) | 1974-09-13 | 1975-03-15 | 1975-09-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-13 | 1979-03-15 | 1979-09-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-13 | 1983-03-15 | 1983-09-14 | $7700.00 | Window Closed / Lapsed |