US4059461A
Expired / Lapsed
US
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Method for improving the crystallinity of semiconductor films by laser beam scanning and the products thereof
Assignee: Massachusetts Institute of Technology
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Filing: 1975-12-10
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Granted: 1977-11-22
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Expires: 1995-12-10
Abstract
Abstract A method is disclosed for improving the crystallinity of semiconductor films by scanning the surface of such films with a shaped, focused laser beam. The laser is matched to the film so that the beam delivers sufficient energy thereto to heat the film above a temperature at which crystallization occurs along the scan track.
Inventors
- 👤 John C. C. Fan
- 👤 Herbert J. Zeiger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:50
CPC Classifications
H; H10; H10F; H10F10/00; H10F10/10; H10F10/18; C; C23; C23C; C23C16/00; C23C16/22; C23C26/00; C23C26/02; C30; C30B; C30B1/00; C30B1/02; C30B1/023; H10F10/14; H10F71/00; H10F71/134; H10P; H10P34/00; H10P34/40; H10P34/42; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/547; Y02P; Y02P70/00; Y02P70/50; Y10; Y10S; Y10S117/00; Y10S117/903; Y10S117/904; Y10S148/00; Y10S148/09; Y10S148/092; Y10S430/00; Y10S430/146
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
47 words
A method for improving the crystallinity of a semiconductor film by scanning it with a focused beam from a continuous wave laser having a wavelength at which the semiconductor film has an absorption coefficient sufficient to allow laser radiation to be absorbed over the semiconductor film thickness.
Claim 2
Independent Claim
47 words
A method for improving the crystallinity of a semiconductor film by scanning it with a focused beam from a continuous wave laser having a wavelength at which the semiconductor film has an absorption coefficient sufficient to allow laser radiation to be absorbed over the semiconductor film thickness.
Claim 3
Dependent Claim
13 words
A method of claim 1 wherein said semiconductor film is a silicon film.
Claim 4
Dependent Claim
15 words
A method of claim 1 wherein said laser is a high power, high efficiency laser.
Claim 5
Dependent Claim
30 words
A method of claim 3 wherein said high power, high efficiency laser has a power output of at least about 3 watts and an efficiency of at least about 1%.
Claim 6
Dependent Claim
15 words
A method of claim 4 wherein said laser beam is focused to a shaped spot.
Claim 7
Dependent Claim
21 words
A method of claim 5 wherein said shaped spot has an area of at least about 10 -4 cm 2 .
Claim 8
Dependent Claim
14 words
A method of claim 6 wherein said semiconductor film is a polycrystalline semiconductor film.
Claim 9
Dependent Claim
13 words
A method of claim 6 wherein said semiconductor film is an amorphous film.
Claim 10
Dependent Claim
13 words
A method of claim 6 wherein said semiconductor film is a germanium film.
Claim 11
Dependent Claim
13 words
A method of claim 6 wherein said semiconductor film is a silicon film.
Claim 12
Dependent Claim
14 words
A method of claim 10 wherein said silicon film is an amorphous silicon film.
Claim 13
Dependent Claim
16 words
A method of claim 11 wherein said high power, high efficiency laser is a Nd:YAG laser.
Claim 14
Dependent Claim
17 words
A method of claim 12 wherein said laser beam is focused and shaped to a slit image.
Claim 15
Dependent Claim
17 words
A method of claim 6 wherein said laser beam is focused and shaped to a slit image.
Claim 16
Dependent Claim
9 words
A film produced by the method of claim 1.
Claim 17
Independent Claim
41 words
A method for producing a crystalline silicon film from an amorphous silicon film by scanning said amorphous film with a focused laser beam produced by a continuous wave Nd:YAG laser at a rate sufficient to produce crystallization within said amorphous film.
Claim 18
Independent Claim
41 words
A method for producing a crystalline silicon film from an amorphous silicon film by scanning said amorphous film with a focused laser beam produced by a continuous wave Nd:YAG laser at a rate sufficient to produce crystallization within said amorphous film.
Claim 19
Dependent Claim
14 words
A method of claim 16 wherein said amorphous silicon film is about 10μm thick.
Claim 20
Dependent Claim
15 words
A method of claim 16 wherein said amorphous silicon film is supported on a substrate.
Claim 21
Dependent Claim
9 words
A film produced by the method of claim 16.
Claim 22
Independent Claim
56 words
A method for fabricating a photovoltaic cell, comprising: a. forming a conductive layer on a substrate; b. depositing a semiconductor film on said conductive layer; c. scanning the semiconductor film with a focused beam from a laser to improve the crystallinity of said semiconductor film; and, d. forming a transparent rectifying contact with the scanned film.
Claim 23
Independent Claim
56 words
A method for fabricating a photovoltaic cell, comprising: a. forming a conductive layer on a substrate; b. depositing a semiconductor film on said conductive layer; c. scanning the semiconductor film with a focused beam from a laser to improve the crystallinity of said semiconductor film; and, d. forming a transparent rectifying contact with the scanned film.
Claim 24
Dependent Claim
15 words
A method of claim 20 wherein said laser is a high power, high efficiency laser.
Claim 25
Dependent Claim
13 words
A method of claim 21 wherein said rectifying contact is a Schottky barrier.
Claim 26
Dependent Claim
13 words
A method of claim 21 wherein said rectifying contact is a p-n junction.
Claim 27
Dependent Claim
14 words
A method of claim 21 wherein said semiconductor film which is deposited is silicon.
Claim 28
Dependent Claim
14 words
A method of claim 24 wherein said silicon film is an amorphous silicon film.
Claim 29
Independent Claim
59 words
A method for fabricating a photovoltaic cell, comprising: a. depositing a semiconductor film on a transparent, conductive substrate; b. forming a rectifying contact between the semiconductor film and substrate; c. scanning the semiconductor film with a focused beam from a laser to improve the crystallinity of said semiconductor film; and, d. forming a conductive layer on the scanned film.
Claim 30
Independent Claim
59 words
A method for fabricating a photovoltaic cell, comprising: a. depositing a semiconductor film on a transparent, conductive substrate; b. forming a rectifying contact between the semiconductor film and substrate; c. scanning the semiconductor film with a focused beam from a laser to improve the crystallinity of said semiconductor film; and, d. forming a conductive layer on the scanned film.
Claim 31
Dependent Claim
15 words
A method of claim 26 wherein said laser is a high power, high efficiency laser.
Claim 32
Dependent Claim
13 words
A method of claim 27 wherein said rectifying contact is a Schottky barrier.
Claim 33
Dependent Claim
14 words
A method of claim 27 wherein said semiconductor film which is deposited is silicon.
Claim 34
Dependent Claim
14 words
A method of claim 29 wherein said silicon film is an amorphous silicon film.
Claim 35
Independent Claim
55 words
A method for producing a crystalline semiconductor film, comprising: a. depositing an amorphous film of a semiconductor on a substrate; and, b. scanning said amorphous film to crystallize it with a laser beam having a wavelength which is significantly absorbed across the thickness of said amorphous film and significantly transmitted by the crystallized semiconductor film.
Claim 36
Independent Claim
55 words
A method for producing a crystalline semiconductor film, comprising: a. depositing an amorphous film of a semiconductor on a substrate; and, b. scanning said amorphous film to crystallize it with a laser beam having a wavelength which is significantly absorbed across the thickness of said amorphous film and significantly transmitted by the crystallized semiconductor film.
Claim 37
Dependent Claim
14 words
A method of claim 31 wherein said laser is a continuous wave Nd:YAG laser.
Claim 38
Dependent Claim
14 words
A method of claim 32 wherein said amorphous film is an amorphous silicon film.
Claim 39
Dependent Claim
14 words
A method of claim 31 wherein said amorphous film is an amorphous germanium film.
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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) | 1980-11-21 | 1981-05-23 | 1981-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-21 | 1985-05-23 | 1985-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-21 | 1989-05-23 | 1989-11-22 | $7700.00 | Window Closed / Lapsed |