Patent US4451303A successfully refreshed from Google Patents.
US4451303A
Expired / Lapsed
US
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Diffusion of aluminum
Assignee: Toshiba Corp
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Filing: 1983-01-05
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Granted: 1984-05-29
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Expires: 2003-01-05
Abstract
Abstract A method for producing a semiconductor element which can form a deep P-type impurity region by a diffusion of aluminum. A porous alumina layer is first formed on a semiconductor substrate. Then, a diffusion-protective layer formed of a material having a large oxygen-diffusion-inhibiting ability such as Al 2 O 3 is formed on the porous alumina layer. Subsequently, aluminum ions are implanted in the porous alumina layer through the diffusion-protective layer. Thereafter, a heat treatment is performed to diffuse the aluminum of the aluminum ion-implanted region in the semiconductor substrate, and a P-type impurity region is formed. Alternatively, a porous alumina layer is formed on the semiconductor substrate, and an aluminum layer is then formed thereon. The diffusion-protective layer is formed on the aluminum layer, and a heat treatment is then performed, thereby diffusing the aluminum forming the aluminum layer in the semiconductor substrate, and a P-type impurity region is thus formed.
Inventors
- 👤 Shunichi Hiraki
- 👤 Kiyoshi Kikuchi
- 👤 Shigeo Yawata
- 👤 Masafumi Miyagawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:09
CPC Classifications
H; H10; H10P; H10P32/00; H10P32/10; H10P32/17; H10P32/171; H10P32/14; H10P32/1408; H10P32/141; H10P32/1412
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
90 words
A method for producing a semiconductor element comprising the steps of: forming a porous alumina layer on a semiconductor substrate; forming a diffusion-protective layer formed of a material having a large oxygen-diffusion-inhibiting ability on said porous alumina layer; implanting aluminum ions into said porous alumina layer through said diffusion-protective layer to form an aluminum ion-implanted region in said porous alumina layer; and heating the structure thus formed to diffuse the aluminum in said aluminum ion-implanted region into said semiconductor substrate, thereby forming a P-type impurity region in said semiconductor substrate.
Claim 2
Independent Claim
90 words
A method for producing a semiconductor element comprising the steps of: forming a porous alumina layer on a semiconductor substrate; forming a diffusion-protective layer formed of a material having a large oxygen-diffusion-inhibiting ability on said porous alumina layer; implanting aluminum ions into said porous alumina layer through said diffusion-protective layer to form an aluminum ion-implanted region in said porous alumina layer; and heating the structure thus formed to diffuse the aluminum in said aluminum ion-implanted region into said semiconductor substrate, thereby forming a P-type impurity region in said semiconductor substrate.
Claim 3
Dependent Claim
30 words
The method according to claim 1, wherein said diffusion-protective layer is formed of a material selected from the group consisting of aluminum oxide, silicon nitride, silicon carbide and aluminum nitride.
Claim 4
Dependent Claim
21 words
The method according to claim 1, wherein said aluminum ions are implanted in the surface portion of said porous aluminum layer.
Claim 5
Independent Claim
79 words
A method for producing a semiconductor element comprising the steps of: forming a porous alumina layer on a semiconductor substrate; forming an aluminum layer on said porous alumina layer; forming a diffusion-protective layer formed of a material having a large oxygen-diffusion-inhibiting ability on said aluminum layer; and heating the structure thus formed to diffuse the aluminum forming said aluminum layer through said porous aluminum layer into said semiconductor substrate, thereby forming a P-type impurity region in said semiconductor substrate.
Claim 6
Independent Claim
79 words
A method for producing a semiconductor element comprising the steps of: forming a porous alumina layer on a semiconductor substrate; forming an aluminum layer on said porous alumina layer; forming a diffusion-protective layer formed of a material having a large oxygen-diffusion-inhibiting ability on said aluminum layer; and heating the structure thus formed to diffuse the aluminum forming said aluminum layer through said porous aluminum layer into said semiconductor substrate, thereby forming a P-type impurity region in said semiconductor substrate.
Claim 7
Dependent Claim
30 words
The method according to claim 4, wherein said diffusion-protective layer is formed of a material selected from the group consisting of aluminum oxide, silicon nitride, silicon carbide and aluminum nitride.
Claim 8
Dependent Claim
26 words
The method according to claim 4, wherein said diffusion-protective layer is formed by converting the surface layer of said aluminum layer into a nonporous alumina layer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-05-29 | 1987-11-28 | 1988-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-29 | 1991-11-28 | 1992-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-29 | 1995-11-28 | 1996-05-29 | $7700.00 | Window Closed / Lapsed |