US4468855A
Expired / Lapsed
US
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Method of making aluminum gate self-aligned FET by selective beam annealing through reflective and antireflective coatings
Assignee: Fujitsu Ltd
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Filing: 1982-08-04
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Granted: 1984-09-04
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Expires: 2002-08-04
Abstract
Abstract A method for producing a semiconductor device comprising the steps of forming a gate insulating layer (3) on a semiconductor substrate having a first conductivity (1) and forming an aluminum gate electrode (4) on the gate insulating layer (3); impurity doped regions (5, 6) are then formed in the semiconductor substrate (1) by means of implantation of impurity ions having a second conductivity opposite that of the first conductivity into the semiconductor substrate (1) using the aluminum gate electrode (4) as a masking material for annealing the impurity doped regions (5, 6). The annealing process occurs by irradiating a beam on the impurity doped regions (5, 6) including the aluminum gate electrode (4). After forming the impurity doped regions (5, 6) in the semiconductor substrate (1), at least the upper surface of the aluminum gate electrode (4) is covered with an insulating layer (7).
Inventors
- 👤 Nobuo Sasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:21
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/013; H10D30/00; H10D30/01; H10D30/021; H10D30/0223; H10D30/60; H10P; H10P34/00; H10P34/40; H10P34/42; H10P95/00; H10P95/90; Y; Y10; Y10S; Y10S148/00; Y10S148/09; Y10S148/091; Y10S148/106; Y10S148/141
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
118 words
A method for producing a semiconductor device formed on a semiconductor substrate of a first conductivity type, comprising the steps of: (a) forming a gate insulating layer on the semiconductor substrate; (b) forming an aluminum gate electrode on the gate insulating layer; (c) forming an impurity doped region in the semiconductor substrate by doping the semiconductor substrate with an impurity having a second conductivity type opposite that of the first conductivity type, using the aluminum gate electrode as a masking material; (d) covering at least the upper surface of the aluminum gate electrode with an insulating layer; and (e) annealing the impurity doped region by irradiating a beam on the impurity doped region and the aluminum gate electrode.
Claim 2
Independent Claim
118 words
A method for producing a semiconductor device formed on a semiconductor substrate of a first conductivity type, comprising the steps of: (a) forming a gate insulating layer on the semiconductor substrate; (b) forming an aluminum gate electrode on the gate insulating layer; (c) forming an impurity doped region in the semiconductor substrate by doping the semiconductor substrate with an impurity having a second conductivity type opposite that of the first conductivity type, using the aluminum gate electrode as a masking material; (d) covering at least the upper surface of the aluminum gate electrode with an insulating layer; and (e) annealing the impurity doped region by irradiating a beam on the impurity doped region and the aluminum gate electrode.
Claim 3
Dependent Claim
56 words
A method according to claim 1, wherein said forming step a comprises forming the gate insulating layer having a thickness t equal to the value calculated by the formula λ(2m-1)/4n, wherein n is the index of refraction of the gate insulating layer, λ is the beam wavelength in a vacuum, and m is a positive integer.
Claim 4
Dependent Claim
59 words
A method according to claim 1, wherein said covering step d comprises covering the aluminum gate electrode with the insulating layer having a thickness t equal to the value calculated by the formula λm/2n, wherein n is the index of refraction of the insulating layer, λ is the beam wavelength in a vacuum, and m is a positive integer.
Claim 5
Dependent Claim
34 words
A method according to claim 1, 2 or 3, wherein the beam in said annealing step e is selected from the group consisting of a laser beam, an electron beam, and a lamp beam.
Claim 6
Dependent Claim
27 words
A method according to claim 1, 2 or 3, wherein said covering step d comprises covering the aluminum layer with the insulating layer which comprises aluminum oxide.
Claim 7
Dependent Claim
27 words
A method according to claim 1, 2 or 3, wherein said covering step d comprises covering the aluminum layer with the insulating layer which comprises silicon nitride.
Claim 8
Dependent Claim
27 words
A method according to claim 1, 2 or 3, wherein said covering step d comprises covering the aluminum layer with the insulating layer which comprises silicon dioxide.
Claim 9
Dependent Claim
24 words
A method according to claim 4, wherein said covering step d comprises covering the aluminum layer with the insulating layer which comprises aluminum oxide.
Claim 10
Dependent Claim
24 words
A method according to claim 4, wherein said covering step d comprises covering the aluminum layer with the insulating layer which comprises silicon nitride.
Claim 11
Dependent Claim
24 words
A method according to claim 4, wherein said covering step d comprises covering the aluminum layer with the insulating layer which comprises silicon dioxide.
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) | 1987-09-04 | 1988-03-05 | 1988-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-04 | 1992-03-05 | 1992-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-04 | 1996-03-05 | 1996-09-04 | $7700.00 | Window Closed / Lapsed |