Patent US4059461A successfully refreshed from Google Patents.
US4059461A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for improving the crystallinity of semiconductor films by laser beam scanning and the products thereof
Assignee: Massachusetts Institute of Technology
•
Filing: 1975-12-10
•
Granted: 1977-11-22
•
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 14:54
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.
References Cited (Backward Citations)
US2855334A
Cited
US3458368A
Cited
US3584183A
Cited
US3585088A
Cited
US3698947A
Cited
US3848104A
Cited
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 |