Patent US4681983A successfully refreshed from Google Patents.
US4681983A
Expired / Lapsed
US
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Semiconductor solar cells
Assignee: Qinetiq Ltd
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Filing: 1985-09-18
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Granted: 1987-07-21
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Expires: 2005-09-18
Abstract
Abstract A photovoltaic solar cell comprises a piece of semiconductor material incorporating a p-type region, an n-type region, a p-n junction between the two, electrodes contacting the two regions, and within its body a lattice defect denuded zone and a lattice defect gettering zone. The defect gettering zone may be a precipitate-rich zone or a region of lattice damage. The denuded zone may include the p-n junction. The semiconductor material may be Si, GaAs or InP. Methods for making the solar cell are described, involving heat treatment steps to produce a denuded zone, nucleating precipitates and generating precipitates. Alternatively precipitation may be nucleated, or a lattice damage zone may be generated, by proton bombardment.
Inventors
- 👤 Tomas Markvart
- 👤 Arthur F. W. Willoughby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:52
CPC Classifications
H; H10; H10F; H10F10/00; H10F10/10; H10F10/14; H10F71/00; H10F71/121; H10F71/127; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/544; Y02E10/547; Y02P; Y02P70/00; Y02P70/50; Y10; Y10S; Y10S148/00; Y10S148/06
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
113 words
A photovoltaic solar cell which comprises a piece of Czochralski-grown semiconductor material incorporating a first region which is p-type, a second region which is n-type, a p-n junction between the two and electrodes on different surfaces of the piece, a first electrode making contact with the first region and a second electrode making contact with the second region, wherein the piece incorporates in its body a lattice defect gettering zone and a defect denuded zone extending between the p-n junction and the lattice defect gettering zone, said denuded zone having a thickness of 100 microns or less as measured from a surface of said cell on which solar radiation is intended to fall.
Claim 2
Dependent Claim
113 words
A photovoltaic solar cell which comprises a piece of Czochralski-grown semiconductor material incorporating a first region which is p-type, a second region which is n-type, a p-n junction between the two and electrodes on different surfaces of the piece, a first electrode making contact with the first region and a second electrode making contact with the second region, wherein the piece incorporates in its body a lattice defect gettering zone and a defect denuded zone extending between the p-n junction and the lattice defect gettering zone, said denuded zone having a thickness of 100 microns or less as measured from a surface of said cell on which solar radiation is intended to fall.
Claim 3
Dependent Claim
18 words
A photovoltaic solar cell according to claim 1 wherein the lattice defect gettering zone is a precipitate-rich zone.
Claim 4
Dependent Claim
31 words
A photovoltaic solar cell according to claim 2 wherein the precipitate is selected from the group consisting of silicon oxide in silicon, arsenic in gallium arsenide, and phosphorus in indium phosphide.
Claim 5
Dependent Claim
20 words
A photovoltaic solar cell according to claim 1 wherein the lattice defect gettering zone is a zone of lattice damage.
Claim 6
Dependent Claim
38 words
A solar cell according to claim 1 wherein the region in which the defect denuded zone is formed extends from one surface of the piece to the lattice defect gettering zone, the p-n junction being in this region.
Claim 7
Dependent Claim
26 words
A photovoltaic solar cell according to claim 1 wherein the semiconductor material is selected from the group consisting of silicon, germanium, gallium arsenide, and indium phosphide.
Claim 8
Dependent Claim
123 words
A photovolatic solar cell according to claim 1 wherein: (a) the piece of semiconductor material is a single crystalline wafer having the p-n junction formed within the wafer near to a first surface thereof, (b) the region extending from the p-n junction to the first surface is of n + -type material, and the body or substrate of the wafer beneath the p-n junction is of p-type material, (c) the region in which the denuded zone is formed extends from the first surface through the part of the wafer where the n-type layer and the p-n junction are formed and into part of the p-type substrate, and (d) the lattice defect gettering zone is formed in the p-type substrate beneath the denuded zone.
Claim 9
Dependent Claim
37 words
A photovoltaic solar cell according to claim 7 wherein the wafer adjacent to the surface thereof remote from the said first surface contains a further denuded zone and a p + -type layer within that denuded zone.
Claim 10
Independent Claim
86 words
A method of making a photovoltaic solar cell comprising the steps of: (a) applying a denuding heat treatment to a wafer of a Czochralski-grown semiconductor material, (b) nucleating precipitates at a lower temperature and in an inert atmosphere, and (c) applying a precipitate yielding anneal at a higher temperature greater than that of step (b) so as to form a denuded zone having a thickness of 100 microns or less as measured from the surface of the cell on which solar radiation is intended to fall.
Claim 11
Independent Claim
86 words
A method of making a photovoltaic solar cell comprising the steps of: (a) applying a denuding heat treatment to a wafer of a Czochralski-grown semiconductor material, (b) nucleating precipitates at a lower temperature and in an inert atmosphere, and (c) applying a precipitate yielding anneal at a higher temperature greater than that of step (b) so as to form a denuded zone having a thickness of 100 microns or less as measured from the surface of the cell on which solar radiation is intended to fall.
Claim 12
Dependent Claim
18 words
A method according to claim 9 wherein step (b) is replaced by a proton bombardment of the wafer.
Claim 13
Dependent Claim
17 words
A method according to claim 9 wherein steps (b) and (c) are replaced by a proton bombardment.
References Cited (Backward Citations)
EP0066461A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-07-20 | 1991-01-19 | 1991-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-20 | 1995-01-19 | 1995-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-20 | 1999-01-19 | 1999-07-21 | $7700.00 | Window Closed / Lapsed |