Patent US4092445A successfully refreshed from Google Patents.
US4092445A
Expired / Lapsed
US
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Process for forming porous semiconductor region using electrolyte without electrical source
Assignee: NEC Corp
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Filing: 1976-11-04
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Granted: 1978-05-30
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Expires: 1996-11-04
Abstract
Abstract A process is disclosed for forming a porous region in a semiconductor device. In the process, a region of a relatively high impurity concentration is formed at a desired region of a semiconductor body of a lower impurity concentration. The semiconductor body is dipped into an electrolyte along with an electrode. The electrode is connected to the semiconductor body, whereby the high impurity concentration region is converted into a porous region.
Inventors
- 👤 Naobumi Tsuzuki
- 👤 Tetsu Koji
- 👤 Kazuo Noguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 14:01
CPC Classifications
H; H10; H10P; H10P50/00; C; C25; C25F; C25F3/00; C25F3/02; C25F3/12; Y; Y10; Y10S; Y10S438/00; Y10S438/96
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
90 words
A process for forming a porous semiconductor comprising the steps of forming a high-concentration region having an impurity concentration of 1 × 10 17 cm -3 to 1 × 10 22 cm -3 in a desired area at a surface of a single crystal semiconductor body, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and directly connecting said semiconductor body to said electrode, thereby converting said high-concentration region into a porous region.
Claim 2
Dependent Claim
90 words
A process for forming a porous semiconductor comprising the steps of forming a high-concentration region having an impurity concentration of 1 × 10 17 cm -3 to 1 × 10 22 cm -3 in a desired area at a surface of a single crystal semiconductor body, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and directly connecting said semiconductor body to said electrode, thereby converting said high-concentration region into a porous region.
Claim 3
Dependent Claim
98 words
A process for forming a porous semiconductor comprising the steps of forming a high-concentration region having an impurity concentration of 1 × 10 17 cm -3 to 1 × 10 22 cm -3 in a part at a surface of a single crystal semiconductor body having the same conductivity type as said high-concentration region, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and directly connecting said semiconductor body to said electrode, thereby converting said high-concentration region into a porous region.
Claim 4
Dependent Claim
98 words
A process for forming a porous semiconductor comprising the steps of forming a high-concentration region having an impurity concentration of 1 × 10 17 cm -3 to 1 × 10 22 cm -3 in a part at a surface of a single crystal semiconductor body having the same conductivity type as said high-concentration region, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and directly connecting said semiconductor body to said electrode, thereby converting said high-concentration region into a porous region.
Claim 5
Dependent Claim
33 words
The process for forming a porous semiconductor as claim in claim 2, wherein the impurity concentration of said high-concentration region is at least ten times as high as that of said surface region.
Claim 6
Dependent Claim
19 words
The process for forming a porous semiconductor as claimed in claim 2, wherein said semiconductor body is of silicon.
Claim 7
Dependent Claim
96 words
A process for forming a porous semiconductor comprising the steps of forming a high-concentration region having an impurity concentration of 1 × 10 17 cm -3 to 1 × 10 22 cm -3 in a desired area at a surface of a single crystal semiconductor body, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and connecting said semiconductor body to said electrode by connecting means containing no electrical source, thereby converting said high-concentration region into a porous region.
Claim 8
Dependent Claim
96 words
A process for forming a porous semiconductor comprising the steps of forming a high-concentration region having an impurity concentration of 1 × 10 17 cm -3 to 1 × 10 22 cm -3 in a desired area at a surface of a single crystal semiconductor body, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and connecting said semiconductor body to said electrode by connecting means containing no electrical source, thereby converting said high-concentration region into a porous region.
Claim 9
Dependent Claim
103 words
A process for forming a porous semiconductor comprising the steps of forming a high concentration having an impurity concentration of 1 × 10 17 cm -3 to 1 × 10 22 cm -3 in a part at a surface of a single crystal semiconductor body having the same conductivity as said high-concentration region, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and connecting said semiconductor body to said electrode by connecting means containing no electrical source, thereby converting said high-concentration region into a porous region.
Claim 10
Dependent Claim
103 words
A process for forming a porous semiconductor comprising the steps of forming a high concentration having an impurity concentration of 1 × 10 17 cm -3 to 1 × 10 22 cm -3 in a part at a surface of a single crystal semiconductor body having the same conductivity as said high-concentration region, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and connecting said semiconductor body to said electrode by connecting means containing no electrical source, thereby converting said high-concentration region into a porous region.
Claim 11
Dependent Claim
33 words
The process for forming a porous semiconductor as claimed in claim 6, wherein said impurity concentration of said high-concentration region is at least 10 times as high as that of said surface region.
Claim 12
Dependent Claim
19 words
The process for forming a porous semiconductor as claimed in claim 6, wherein said semiconductor body is of silicon.
Claim 13
Dependent Claim
92 words
A process for forming a porous semiconductor comprising the steps of forming a high-concentration region having an impurity concentration of 1 × 10 17 cm -3 to 1 × 10 22 cm -3 in a desired area at a surface of a single crystal semiconductor body, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and connecting said semiconductor body to said electrode by resistive means, thereby converting said high-concentration region into a porous region.
Claim 14
Dependent Claim
92 words
A process for forming a porous semiconductor comprising the steps of forming a high-concentration region having an impurity concentration of 1 × 10 17 cm -3 to 1 × 10 22 cm -3 in a desired area at a surface of a single crystal semiconductor body, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and connecting said semiconductor body to said electrode by resistive means, thereby converting said high-concentration region into a porous region.
Claim 15
Dependent Claim
100 words
A process for forming a porous semiconductor comprising the steps of forming a high-concentration region having an impurity concentration of 1 × 10 17 cm -3 to 1 × 10 22 cm -3 in a part at a surface of a single crystal semiconductor body having the same conductivity type as said high-concentration region, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and connecting said semiconductor body to said electrode by resistive means, thereby converting said high-concentration region into a porous region.
Claim 16
Dependent Claim
100 words
A process for forming a porous semiconductor comprising the steps of forming a high-concentration region having an impurity concentration of 1 × 10 17 cm -3 to 1 × 10 22 cm -3 in a part at a surface of a single crystal semiconductor body having the same conductivity type as said high-concentration region, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and connecting said semiconductor body to said electrode by resistive means, thereby converting said high-concentration region into a porous region.
Claim 17
Dependent Claim
33 words
The process for forming a porous semiconductor as claimed in claim 10, wherein said impurity concentration of said high-concentration region is at least ten times as high as that of said surface region.
Claim 18
Dependent Claim
19 words
The process for forming a porous semiconductor as claimed in claim 10, wherein said semiconductor body is of silicon.
Claim 19
Dependent Claim
95 words
A process for converting a single crystal semiconductor into a porous semiconductor, comprising the steps of: forming an n-type high-concentration region having an impurity concentration of 1 × 10 17 to 1 × 10 22 cm -3 in a desired area at a surface region of a single crystal semiconductor body, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and directly connecting said semiconductor body to said electrode, thereby converting said high-concentration region into a porous region.
Claim 20
Dependent Claim
95 words
A process for converting a single crystal semiconductor into a porous semiconductor, comprising the steps of: forming an n-type high-concentration region having an impurity concentration of 1 × 10 17 to 1 × 10 22 cm -3 in a desired area at a surface region of a single crystal semiconductor body, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; placing said semiconductor body and an electrode into an electrolyte; and directly connecting said semiconductor body to said electrode, thereby converting said high-concentration region into a porous region.
Claim 21
Dependent Claim
34 words
The process as set forth in claim 13, wherein said impurity concentration of said high concentration region is at least ten times as high as that of the impurity concentration of said surface region.
Claim 22
Dependent Claim
32 words
The process as set forth in claim 13, wherein said electrolyte is an aqueous solution of a halide, the concentration of said halide being at least 10wt% but below the saturated concentration.
Claim 23
Dependent Claim
104 words
A process for forming a porous insulating material, comprising the steps of: forming an n-type high-concentration region having an impurity concentration of 1 × 10 17 to 1 × 10 22 cm -3 in a desired area of a surface region of a single crystal semiconductor body, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; dipping said semiconductor body and an electrode into an electrolyte; directly connecting said semiconductor body to said electrode, thereby making said high-concentration region porous; and heating said semiconductor body in an oxidizing atmosphere, thereby converting the porous region into an oxide.
Claim 24
Dependent Claim
104 words
A process for forming a porous insulating material, comprising the steps of: forming an n-type high-concentration region having an impurity concentration of 1 × 10 17 to 1 × 10 22 cm -3 in a desired area of a surface region of a single crystal semiconductor body, said surface region having an impurity concentration of below 1 × 10 17 cm -3 ; dipping said semiconductor body and an electrode into an electrolyte; directly connecting said semiconductor body to said electrode, thereby making said high-concentration region porous; and heating said semiconductor body in an oxidizing atmosphere, thereby converting the porous region into an oxide.
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) | 1981-05-29 | 1981-11-28 | 1982-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-29 | 1985-11-28 | 1986-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-29 | 1989-11-28 | 1990-05-30 | $7700.00 | Window Closed / Lapsed |