Patent US5010040A successfully refreshed from Google Patents.
US5010040A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of fabricating solar cells
Assignee: Schott Solar CSP Inc
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Filing: 1988-12-30
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Granted: 1991-04-23
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Expires: 2008-12-30
Abstract
Abstract A method of forming a metallization pattern on a substrate used in the fabrication of a solar cell or other semiconductor device. The metallization pattern is formed by (1) hydrogen passivating a silicon substrate having a P/N junction formed therein adjacent one surface of the substrate, with a damaged surface layer being formed in conjunction with the hydrogen passivation process, and (2) laser annealing selected portions of said damaged layer whereby said selected portions form a metallization pattern to which selected metals will securely adhere when applied by immersion plating. The foregoing fabrication steps may be performed simultaneously. A layer of material comprising SiO x may be redeposited on the one surface of the substrate as part of the hydrogen passivation procedure. In the laser annealing step, sections of the redeposited material scanned by the laser beam are ablated and the exposed underlying damaged surface layer is annealed.
Inventors
- 👤 Zinovy Y. Vayman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:36
CPC Classifications
H; H10; H10F; H10F71/00; H10F71/121; H10F71/129; H10F77/00; H10F77/20; H10F77/206; H10F77/211; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/547; Y02P; Y02P70/00; Y02P70/50; Y10; Y10S; Y10S438/00; Y10S438/94
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
134 words
A method of forming metallization patterns on a silicon substrate that is to be used to form a photovoltaic cell comprising in sequence the steps of: (a) exposing a first surface of said substrate to a hydrogen ion beam of an intensity and for a duration sufficient to hydrogen passivate the substrate and form a damaged surface layer to which metals deposited by immersion plating will only poorly adhere; and (b) scanning selected portions of said first surface with a laser beam of an intensity and for a duration sufficient to anneal selected portions of said damaged layer so as to create a metallization pattern consisting of non-passivated areas of said first surface to which selected metals will securely adhere, said metallization pattern being created in an environment substantially free of chemical etching substances.
Claim 2
Independent Claim
134 words
A method of forming metallization patterns on a silicon substrate that is to be used to form a photovoltaic cell comprising in sequence the steps of: (a) exposing a first surface of said substrate to a hydrogen ion beam of an intensity and for a duration sufficient to hydrogen passivate the substrate and form a damaged surface layer to which metals deposited by immersion plating will only poorly adhere; and (b) scanning selected portions of said first surface with a laser beam of an intensity and for a duration sufficient to anneal selected portions of said damaged layer so as to create a metallization pattern consisting of non-passivated areas of said first surface to which selected metals will securely adhere, said metallization pattern being created in an environment substantially free of chemical etching substances.
Claim 3
Dependent Claim
38 words
A method according to claim 1 wherein said substrate has a bulk region, and further wherein said intensity of and duration of exposure to said hydrogen ion beam are selected to achieve hydrogen passivation of said bulk region.
Claim 4
Dependent Claim
18 words
A method according to claim 1 wherein said hydrogen ion beam is created by a Kaufman ion source.
Claim 5
Dependent Claim
27 words
A method according to claim 1 wherein said first surface is exposed to said hydrogen ion beam for a time period of between 1 and 4 minutes.
Claim 6
Dependent Claim
82 words
A method according to claim 3 wherein said Kaufman ion source is operated so that (1) said hydrogen ion beam has a pressure of between 20 and 50 mTorr (of hydrogen) and current density of between 1 and 3 milliamperes/cm 2 at said first surface, (2) a potential of about 1700 volts d.c. is created between said Kaufman ion source and said first surface, and (3) hydrogen is consumed at a flow rate ranging from 25 to 40 cm 3 per minute.
Claim 7
Dependent Claim
17 words
A method according to claim 1 wherein said laser beam is generated by a YAG neodimium laser.
Claim 8
Dependent Claim
16 words
A method according to claim 1 wherein said laser beam is generated by an excimer laser.
Claim 9
Dependent Claim
17 words
A method according to claim 1 wherein said laser beam has approximately a one watt power output.
Claim 10
Dependent Claim
70 words
A method according to claim 1, said metallization pattern comprising a plurality of elongate fingers, wherein said scanning step comprises: generating said laser beam so that the latter forms a circular point on said first surface having a diameter approximately equal to the width of one of said plurality of elongate fingers; and moving said circular point across said first surface at a rate of about three inches per second.
Claim 11
Dependent Claim
105 words
A method according to claim 1 wherein said exposing step includes depositing a thin layer of material comprising SiO x on at least a portion of said first surface of said substrate, further wherein said scanning step includes scanning those sections of said thin layer of material which are deposited on said selected portions of said first surface with said laser beam for said intensity and for said duration whereby (1) said sections of said thin layer of material are ablated thereby exposing said damaged surface layer and (2) said exposed damaged surface layer is annealed so that said selected metals will adhere securely thereto.
Claim 12
Independent Claim
134 words
A method of forming metallization patterns on a silicon substrate that is to be used to form a photovoltaic cell comprising simultaneously performing the steps of: (a) exposing a first surface of said substrate to a hydrogen ion beam of an intensity and for a duration sufficient to hydrogen passivate the substrate and form a damaged surface layer to which metals deposited by immersion plating will only poorly adhere; and (b) scanning selected portions of said first surface with a laser beam of an intensity and for a duration sufficient to anneal selected portions of said damaged layer so as to create a metallization pattern consisting of non-passivated areas of said first surface to which selected metals will securely adhere, said metallization pattern being created in an environment substantially free of chemical etching substances.
Claim 13
Independent Claim
134 words
A method of forming metallization patterns on a silicon substrate that is to be used to form a photovoltaic cell comprising simultaneously performing the steps of: (a) exposing a first surface of said substrate to a hydrogen ion beam of an intensity and for a duration sufficient to hydrogen passivate the substrate and form a damaged surface layer to which metals deposited by immersion plating will only poorly adhere; and (b) scanning selected portions of said first surface with a laser beam of an intensity and for a duration sufficient to anneal selected portions of said damaged layer so as to create a metallization pattern consisting of non-passivated areas of said first surface to which selected metals will securely adhere, said metallization pattern being created in an environment substantially free of chemical etching substances.
Claim 14
Independent Claim
223 words
A method of fabricating a photovoltaic cell comprising in sequence the steps of: (a) providing a crystalline substrate having opposing first and second surfaces; (b) forming a P/N junction in said substrate adjacent said first surface; (c) exposing said first surface to a hydrogen ion beam of an intensity and for a duration sufficient to hydrogen passivate the substrate, wherein a damaged surface layer to which metals deposited by immersion plating will only poorly adhere is formed in conjunction with said hydrogen passivation of the substrate, said ion beam being created by a Kaufman ion source; (d) scanning selected portions of said damaged surface layer with a laser beam of an intensity and for a duration sufficient to anneal said selected portions and thereby create a pattern of regions on said first surface to which metals deposited by immersion plating will securely adhere, said pattern being created in an environment substantially free of chemical etching substances and said laser beam being controlled so that said laser beam does not cause deterioration of said P/N junction; (e) applying a coating of aluminum to said second surface and thereafter heating said silicon substrate to a temperature and for a time sufficient to cause said coating to alloy with said silicon substrate; and (f) depositing electrodes by immersion plating on said regions of said first surface.
Claim 15
Independent Claim
223 words
A method of fabricating a photovoltaic cell comprising in sequence the steps of: (a) providing a crystalline substrate having opposing first and second surfaces; (b) forming a P/N junction in said substrate adjacent said first surface; (c) exposing said first surface to a hydrogen ion beam of an intensity and for a duration sufficient to hydrogen passivate the substrate, wherein a damaged surface layer to which metals deposited by immersion plating will only poorly adhere is formed in conjunction with said hydrogen passivation of the substrate, said ion beam being created by a Kaufman ion source; (d) scanning selected portions of said damaged surface layer with a laser beam of an intensity and for a duration sufficient to anneal said selected portions and thereby create a pattern of regions on said first surface to which metals deposited by immersion plating will securely adhere, said pattern being created in an environment substantially free of chemical etching substances and said laser beam being controlled so that said laser beam does not cause deterioration of said P/N junction; (e) applying a coating of aluminum to said second surface and thereafter heating said silicon substrate to a temperature and for a time sufficient to cause said coating to alloy with said silicon substrate; and (f) depositing electrodes by immersion plating on said regions of said first surface.
Claim 16
Independent Claim
214 words
A method of fabricating a photovoltaic cell comprising in sequence the steps of: (a) providing a crystalline substrate having opposing first and second surfaces; (b) forming a P/N junction in said substrate adjacent said first surface; (c) applying a coating of aluminum to said second surface and thereafter heating said silicon substrate to a temperature and for a time sufficient to cause said coating to alloy with said silicon substrate; (d) exposing said first surface to a hydrogen ion beam of an intensity and for a duration sufficient to hydrogen passivate the substrate, wherein a damaged surface layer to which metals deposited by immersion plating will only poorly adhere is formed in conjunction with said hydrogen passivation of the substrate; (e) scanning selected portions of said damaged surface layer with a laser beam of an intensity and for a duration sufficient to anneal said selected portions and thereby create a pattern of regions on said first surface to which metals deposited by immersion plating will securely adhere, said pattern being created in an environment substantially free of chemical etching substances and said laser beam being controlled so that said laser beam does not cause deterioration of said P/N junction; and (f) depositing an electrode by immersion plating on said regions of said first surface.
Claim 17
Independent Claim
214 words
A method of fabricating a photovoltaic cell comprising in sequence the steps of: (a) providing a crystalline substrate having opposing first and second surfaces; (b) forming a P/N junction in said substrate adjacent said first surface; (c) applying a coating of aluminum to said second surface and thereafter heating said silicon substrate to a temperature and for a time sufficient to cause said coating to alloy with said silicon substrate; (d) exposing said first surface to a hydrogen ion beam of an intensity and for a duration sufficient to hydrogen passivate the substrate, wherein a damaged surface layer to which metals deposited by immersion plating will only poorly adhere is formed in conjunction with said hydrogen passivation of the substrate; (e) scanning selected portions of said damaged surface layer with a laser beam of an intensity and for a duration sufficient to anneal said selected portions and thereby create a pattern of regions on said first surface to which metals deposited by immersion plating will securely adhere, said pattern being created in an environment substantially free of chemical etching substances and said laser beam being controlled so that said laser beam does not cause deterioration of said P/N junction; and (f) depositing an electrode by immersion plating on said regions of said first surface.
Claim 18
Dependent Claim
19 words
A method according to claim 13 wherein said ion beam is created by operation of a Kaufman ion source.
References Cited (Backward Citations)
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| 7.5 Years (Year 8) | 1998-04-22 | 1998-10-22 | 1999-04-23 | $3760.00 | Window Closed / Lapsed |
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