US5340410A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for manufacturing polycrystalline silicon thin-film solar cells
Assignee: Siemens AG
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Filing: 1992-11-03
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Granted: 1994-08-23
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Expires: 2012-11-03
Abstract
Abstract The present invention provides an improved method for manufacturing highly efficient and especially thin polycrystalline silicon thin-film solar cells. More particularly, the present invention provides a silicon nucleation layer produced on amorphous substrates with a nucleation layer being selectively etched until uniformly <111> orientated nuclei remain. A silicon thin-film grown thereover is coarse-crystalline, has grain boundaries residing perpendicular to the substrate and has a pyramid structure as a consequence of the uniform orientation. High photocurrents can already be achieved with solar cells manufactured therefrom beginning with a layer thickness of 10 μm.
Inventors
- 👤 Arthur Endroes
- 👤 Wolfgang Kruehler
- 👤 Richard Einzinger
- 👤 Rolf Plaettner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 19:21
CPC Classifications
H; H10; H10F; H10F71/00; H10F71/121; H10F71/1221; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/546; Y02P; Y02P70/00; Y02P70/50
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
107 words
A method for manufacturing polycrystalline solar cells, comprising the steps of: (a) producing a polycrystalline silicon nucleation layer on an electrically conductive substrate, said silicon nucleation layer containing silicon crystallites in <111> orientation; (b) selectively etching the nucleation layer until only said crystallites having <111> orientation remain as nuclei on the substrate; (c) repeating steps (a) and (b) until a substrate having a selected nucleus density and nucleus size is obtained; (d) growing a polycrystalline silicon thin-film corresponding to the <111> nucleus orientation over the substrate obtained in step (c); producing a pn-junction in the thin-film; and applying electrical contacts on a front-side surface of said thin-film.
Claim 2
Independent Claim
107 words
A method for manufacturing polycrystalline solar cells, comprising the steps of: (a) producing a polycrystalline silicon nucleation layer on an electrically conductive substrate, said silicon nucleation layer containing silicon crystallites in <111> orientation; (b) selectively etching the nucleation layer until only said crystallites having <111> orientation remain as nuclei on the substrate; (c) repeating steps (a) and (b) until a substrate having a selected nucleus density and nucleus size is obtained; (d) growing a polycrystalline silicon thin-film corresponding to the <111> nucleus orientation over the substrate obtained in step (c); producing a pn-junction in the thin-film; and applying electrical contacts on a front-side surface of said thin-film.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein step (a) is further defined by producing the polycrystalline silicon nucleation layer on an electrically conductive graphite substrate.
Claim 4
Dependent Claim
24 words
The method of claim 1 wherein step (a) is further defined by producing the nucleation layer from silane with a chemical vapor deposition method.
Claim 5
Dependent Claim
21 words
The method of claim 1 wherein step (b) is further defined by etching the nucleation layer with aqueous potassium hydroxide solution.
Claim 6
Dependent Claim
38 words
The method of claim 1 wherein step (d) is further defined by producing the thin-film in a thickness of about 10 to 50 μm with an average nucleus spacing of about 1 to 5 times the layer thickness.
Claim 7
Dependent Claim
38 words
The method of claim 1 wherein step (d) is further defined by producing the thin-film in a thickness of about 10 to 30 μm with an average nucleus spacing of about 1 to 5 times the layer thickness.
Claim 8
Dependent Claim
36 words
The method of claim 1 wherein step (d) is further defined by growing the polycrystalline silicon thin-film on the substrate provided with the nuclei according to the liquid phase deposition method from a silicon-saturated metal melt.
Claim 9
Dependent Claim
42 words
The method of claim 1 wherein step (a) is further defined by producing the nucleation layer with a low pressure chemical vapor deposition and step (b) of selectively etching the nucleation layer is further defined as plasma etching in the same reactor.
Claim 10
Dependent Claim
76 words
A polycrystalline thin-film cell comprising: a graphite substrate, an approximately 10 to 50 μm thick polycrystalline silicon thin-film layer with <111> orientation of the crystallites disposed on said substrate, the silicon thin-film layer having a pyramid like surface, the crystallites having an average grain size of about 10 to 50 micrometers, a pn junction in the silicon thin-film layer, and a finger electrode forming an electrical contact on a front-side surface of the silicon thin-film layer.
Claim 11
Dependent Claim
76 words
A polycrystalline thin-film cell comprising: a graphite substrate, an approximately 10 to 50 μm thick polycrystalline silicon thin-film layer with <111> orientation of the crystallites disposed on said substrate, the silicon thin-film layer having a pyramid like surface, the crystallites having an average grain size of about 10 to 50 micrometers, a pn junction in the silicon thin-film layer, and a finger electrode forming an electrical contact on a front-side surface of the silicon thin-film layer.
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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) | 1997-08-22 | 1998-02-21 | 1998-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-08-22 | 2002-02-21 | 2002-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-08-22 | 2006-02-21 | 2006-08-23 | $7700.00 | Window Closed / Lapsed |