Patent US4292091A successfully refreshed from Google Patents.
US4292091A
Expired / Lapsed
US
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Method of producing semiconductor devices by selective laser irradiation and oxidation
Assignee: Fujitsu Ltd
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Filing: 1980-02-25
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Granted: 1981-09-29
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Expires: 2000-02-25
Abstract
Abstract A method of producing a semiconductor device comprises a step of forming a field isolating oxide layer from an amorphous silicon layer by oxidation at a relatively low temperature. Prior to the oxidizing treatment, a portion of the amorphous silicon layer is recrystallized into a single-crystalline silicon layer by laser irradiation.
Inventors
- 👤 Ryoiku Togei
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:58
CPC Classifications
H; H10; H10W; H10W10/00; H10W10/10; H10W10/17; H10P; H10P14/00; H10P14/20; H10P14/29; H10P14/2901; H10P14/2902; H10P14/2905; H10P14/34; H10P14/3402; H10P14/3404; H10P14/3411; H10P14/38; H10P14/3802; H10P14/3808; H10P34/00; H10P34/40; H10P34/42; H10P95/00; H10W10/01; H10W10/011; H10W10/014; H10W10/0142; Y; Y10; Y10S; Y10S148/00; Y10S148/093
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
113 words
A method of producing a desired semiconductor or circuit element comprising the steps of: forming an amorphous silicon layer on a substrate; forming a patterned mask film on said amorphous silicon layer to shield a portion thereof, thereby defining shielded and exposed areas of said amorphous silicon layer; selectively annealing said amorphous silicon layer with a laser beam to change said amorphous silicon layer into a single-crystalline silicon layer except for said shielded area of said amorphous silicon layer; removing said patterned mask film; oxidizing the remaining amorphous silicon layer to change it into a field isolating oxide layer; and forming the desired semiconductor element or circuit element in said single-crystalline silicon layer.
Claim 2
Independent Claim
113 words
A method of producing a desired semiconductor or circuit element comprising the steps of: forming an amorphous silicon layer on a substrate; forming a patterned mask film on said amorphous silicon layer to shield a portion thereof, thereby defining shielded and exposed areas of said amorphous silicon layer; selectively annealing said amorphous silicon layer with a laser beam to change said amorphous silicon layer into a single-crystalline silicon layer except for said shielded area of said amorphous silicon layer; removing said patterned mask film; oxidizing the remaining amorphous silicon layer to change it into a field isolating oxide layer; and forming the desired semiconductor element or circuit element in said single-crystalline silicon layer.
Claim 3
Dependent Claim
60 words
A method as claimed n claim 1, wherein a silicon dioxide layer is also formed on said single-crystalline silicon layer, simultaneously with said oxidizing step, and wherein said method further comprises a step of removing the silicon dioxide layer, which is formed on said single-crystalline silicon layer prior to said step of forming the semiconductor element or the circuit element.
Claim 4
Dependent Claim
15 words
A method as claimed in claim 1, wherein said substrate comprises a single-crystalline silicon substrate.
Claim 5
Dependent Claim
14 words
A method as claimed in claim 1, wherein said substrate comprises a sapphire substrate.
Claim 6
Dependent Claim
31 words
A method as claimed in claim 1, wherein said oxidizing step of the remaining amorphous silicon layer is carried out at a temperature in the range of 800° to 1000° C.
Claim 7
Dependent Claim
18 words
The method of claim 3, wherein said single-crystalline silicon substrate further comprises a heavy concentration of an impurity.
Claim 8
Dependent Claim
12 words
The method of claim 6, wherein said substrate is of low resistivity.
Claim 9
Dependent Claim
18 words
The method of claim 1, wherein said patterned mask film comprises a metal having a high melting point.
Claim 10
Dependent Claim
11 words
The method of claim 8, wherein said mask film comprises molybdenum.
Claim 11
Dependent Claim
14 words
The method of claim 1, wherein said laser beam comprises a continuous-wave laser beam.
Claim 12
Dependent Claim
11 words
The method of claim 1, wherein said laser beam is pulsed.
Claim 13
Dependent Claim
22 words
The method of claim 11, wherein said laser beam comprises an output power of the approximate order of 1 to 5 megawatts.
Claim 14
Dependent Claim
20 words
The method of claim 1, wherein said selective annealing step comprises scanning said amorphous silicon layer with said laser beam.
Claim 15
Dependent Claim
18 words
The method of claim 3, wherein said single-crystalline silicon substrate comprises a crystalline orientation in the (100) plane.
Claim 16
Dependent Claim
17 words
The method of claim 1, wherein said step of removing said patterned mask film uses an etchant.
Claim 17
Dependent Claim
17 words
The method of claim 2, wherein said step of silicon dioxide removal comprises application of hydrofluoric acid.
Claim 18
Dependent Claim
20 words
The method of claim 16, wherein said step of silicon dioxide removal comprises submerging said substrate into said hydrofluoric acid.
Claim 19
Dependent Claim
32 words
The method of claim 17, wherein said substrate is removed from said hydrofluoric acid as soon as said silicon dioxide layer that is atop said single-crystalline silicon layer has been removed therefrom.
Claim 20
Dependent Claim
13 words
The method of claim 1, wherein said amorphous silicon layer is relatively thin.
Claim 21
Dependent Claim
14 words
The method of claim 19, wherein said field isolating oxide layer is relatively narrow.
Claim 22
Dependent Claim
31 words
The method of claim 1, further comprising the step of implanting selected impurities into selected respective regions of said amorphous silicon layer, before said step of forming said patterned mask film.
Claim 23
Independent Claim
104 words
A method of producing a semiconductor device or circuit element comprising the steps of: forming a polysilicon layer on a substrate; forming a patterned mask film on said polysilicon layer to shield a portion thereof, thereby defining shielded and exposed areas of said polysilicon layer; selectively annealing said polysilicon layer with a laser beam to change said polysilicon layer into a single-crystalline silicon layer except for said shielded area of said polysilicon layer; removing said patterned mask film; oxidizing the remaining polysilicon layer to change it into a field isolating oxide layer; and forming the semiconductor element or circuit element in said polysilicon layer.
Claim 24
Independent Claim
104 words
A method of producing a semiconductor device or circuit element comprising the steps of: forming a polysilicon layer on a substrate; forming a patterned mask film on said polysilicon layer to shield a portion thereof, thereby defining shielded and exposed areas of said polysilicon layer; selectively annealing said polysilicon layer with a laser beam to change said polysilicon layer into a single-crystalline silicon layer except for said shielded area of said polysilicon layer; removing said patterned mask film; oxidizing the remaining polysilicon layer to change it into a field isolating oxide layer; and forming the semiconductor element or circuit element in said polysilicon layer.
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) | 1984-09-28 | 1985-03-30 | 1985-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-28 | 1989-03-30 | 1989-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-28 | 1993-03-30 | 1993-09-29 | $7700.00 | Window Closed / Lapsed |