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US4778478A
Expired / Lapsed
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Method of making thin film photovoltaic solar cell
Assignee: University of Delaware
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Filing: 1985-12-20
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Granted: 1988-10-18
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Expires: 2005-12-20
Abstract
Abstract Solar cell quality semiconductors are grown using a constant temperature sliding boat liquid phase process in a continuous or semi-continuous mode. The growth is driven by applying a temperature gradient or other gradient across the melt, with the substrate at a cooler temperature, after thermal equilibrium is obtained between the solution and the substrate. Growth occurs from the bottom of the solution to prevent contamination of the growth layers by extraneous particles in the solution.
Inventors
- 👤 Allen M. Barnett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:12
CPC Classifications
H; H10; H10F; H10F71/00; H10F71/125; H10F71/121; H10F71/1253; H10F71/127; H10F77/00; H10F77/40; H10F77/42; H10F77/484; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/52; Y02E10/543; Y02E10/544; Y02E10/547; Y02P; Y02P70/00; Y02P70/50; Y10; Y10S; Y10S117/00; Y10S117/914; Y10S438/00; Y10S438/907
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
148 words
In a method of fabricating a thin film photovoltaic device, which includes as its components a substrate functioning as a support and as an opaque electrical contact, semiconductor layers functioning as an absorber-generator and as a collector-converter, and transparent electrical contact means, said method including depositing at least one semiconductor layer from a liquid saturated solution of a semiconductor material dissolved in a solvent, the improvement being the steps of: a. applying over the substrate a metallurgical barrier layer to prevent contamination of the liquid saturated solution and of the semiconductor layers by the substrate; b. continuously depositing over the metallurgical barrier layer a first semiconductor layer of a first selected conductivity type by moving the substrate through a liquid saturated solution of a first semiconductor material dissolved in a solvent and applying a gradient across the saturated solution to drive the growth of the first semiconductor layer.
Claim 2
Dependent Claim
148 words
In a method of fabricating a thin film photovoltaic device, which includes as its components a substrate functioning as a support and as an opaque electrical contact, semiconductor layers functioning as an absorber-generator and as a collector-converter, and transparent electrical contact means, said method including depositing at least one semiconductor layer from a liquid saturated solution of a semiconductor material dissolved in a solvent, the improvement being the steps of: a. applying over the substrate a metallurgical barrier layer to prevent contamination of the liquid saturated solution and of the semiconductor layers by the substrate; b. continuously depositing over the metallurgical barrier layer a first semiconductor layer of a first selected conductivity type by moving the substrate through a liquid saturated solution of a first semiconductor material dissolved in a solvent and applying a gradient across the saturated solution to drive the growth of the first semiconductor layer.
Claim 3
Dependent Claim
18 words
In the method of claim 1 including maintaining the substrate as the cooler end of a temperature gradient.
Claim 4
Dependent Claim
15 words
In the method of claim 2 wherein the substrate is cooled by a heat sink.
Claim 5
Dependent Claim
27 words
In the method of claim 2 wherein the substrate is cooled by a flowing cool gas and the gradient is maintained by controlling the flow of gas.
Claim 6
Dependent Claim
29 words
In the method of claim 2 wherein the step of applying a gradient includes applying heat to the saturated solution distal to the cooler end of the temperature gradient.
Claim 7
Dependent Claim
25 words
In the method of claim 1 wherein the step of applying a gradient includes applying an electric field between the saturated solution and the substrate.
Claim 8
Dependent Claim
18 words
In the method of claim I wherein the temperature of the saturated solution is essentially constant in time.
Claim 9
Dependent Claim
18 words
In the method of claim 1 wherein solid semiconductor material is floated on top of the saturated solution.
Claim 10
Dependent Claim
15 words
In the method of claim 8 wherein the solid semiconductor material is replenished over time.
Claim 11
Dependent Claim
15 words
In the method of claim 1 wherein the substrate is placed beneath the saturated solution.
Claim 12
Dependent Claim
23 words
In the method of claim 1 wherein the semiconductor layer is deposited continuously over a continuous substrate by continuous movement of the substrate.
Claim 13
Dependent Claim
28 words
In the method of claim 1 wherein a non-continuous substrate is placed in a moveable slide and the semiconductor layer is deposited semi-continuously by movement of the slide.
Claim 14
Dependent Claim
27 words
In the method of claim 1 wherein the semiconductor material is selected from silicon, gallium arsenide, cadmium telluride, indium phosphide, zine phosphide, cadmium sulfide, and zinc-cadmium sulfide.
Claim 15
Dependent Claim
13 words
In the method of claim 1 wherein the solvent is a molten metal.
Claim 16
Dependent Claim
13 words
In the method of claim 1 wherein the solvent is a molten compound.
Claim 17
Dependent Claim
25 words
In the method of claim 1 wherein the saturated solution includes dopant material selected to provide the semiconductor layer with conductivity of a selected type.
Claim 18
Dependent Claim
19 words
In the method of claim 1 wherein the saturated solution is a saturated solution of silicon in molten tin.
Claim 19
Dependent Claim
27 words
In the method of claim 17 wherein the saturated solution comprises six atomic percent silicon and the solution is maintained at a temperature of 950 degrees centigrade.
Claim 20
Dependent Claim
26 words
In the method of claim 17 wherein the semiconductor layer is silicon having p-type conductivity and the dopant material is selected from boron, aluminum, and gallium.
Claim 21
Dependent Claim
26 words
In the method of claim 1 including the further step of depositing a second semiconductor layer of an opposite conductivity type over the first semiconductor layer.
Claim 22
Dependent Claim
24 words
In the method of claim 20 wherein the first and second semiconductor layers are of the same semiconductor material in a homojunction photovoltaic device.
Claim 23
Dependent Claim
22 words
In the method of claim 20 wherein the second semiconductor layer is of a different semiconductor material in a heterojunction photovoltaic device.
Claim 24
Dependent Claim
55 words
In the method of claim 20 wherein the step of depositing the second semiconductor layer is depositing from a second liquid saturated solution of a second semiconductor material dissolved in a solvent by applying a gradient across the second saturated solution to drive the growth of the second semiconductor layer over the first semiconductor layer.
Claim 25
Dependent Claim
26 words
In the method of claim 23 wherein the second saturated solution includes dopant material selected to provide the second semiconductor layer with the selected conductivity type.
Claim 26
Dependent Claim
28 words
In the method of claim 23 wherein the second saturated solution is a saturated solution of silicon in molten tin and the dopant is phosphorus, arsenic, or antimony.
Claim 27
Dependent Claim
36 words
In the method of claim 1 including the step of texturing the surface of the substrate upon which the metallurgical barrier layer is to be applied to a predetermined geometrical shape to provide for optical confinement.
Claim 28
Dependent Claim
42 words
In the method of claim 26 wherein the substrate is a metal and the texturing step is impressing a roller having a surface with a selected reflector geometry against the substrate surface upon which the metallurgical barrier layer is to be applied.
Claim 29
Dependent Claim
18 words
In the method of claim 26 wherein the metallurgical barrier layer is an optically transparent metallurgical barrier layer.
Claim 30
Dependent Claim
25 words
In the method of claim 26 wherein the metallurgical barrier layer is an optical reflection metallurgical barrier layer to provide for enhanced reflection of light.
Claim 31
Dependent Claim
18 words
In the method of claim 1 wherein the metallurgical barrier layer is an optically transparent metallurgical barrier layer.
Claim 32
Dependent Claim
25 words
In the method of claim 1 wherein the metallurgical barrier layer is an optical reflection metallurgical barrier layer to provide for enhanced reflection of light.
Claim 33
Dependent Claim
45 words
In the method of claim 1 wherein the liquid saturated solution is cooled sufficiently to deposit the semiconductor layer over the substrate and including the steps of removing the substrate from the growth solutions, reheating the solution, replenishing the semiconductor material and repeating the sequence.
Claim 34
Independent Claim
154 words
A method of fabricating a thin film photovoltaic device on a substrate selected from a group consisting of metals, metal alloys, and metallurgical grade semiconductors, comprising the steps of: (a) texturing the substrate; (b) applying over the textured substrate an optically transparent, conducting metallurgical barrier layer; (c) continuously depositing over the barrier layer a first semiconductor layer of a first selected conductivity type by moving the substrate through a liquid saturated solution of a first semiconductor material dissolved in a solvent and applying a temperature gradient across the saturated solution to drive the growth of the first semiconductor layer; (d) continuously depositing a second semiconductor layer having a conductivity type opposite the first selected conductivity type by moving the substrate through an additional liquid saturated solution of a second semiconductor material dissolved in a solvent and applying a temperature gradient across the second saturated solution to drive the growth of the second semiconductor layer.
Claim 35
Independent Claim
154 words
A method of fabricating a thin film photovoltaic device on a substrate selected from a group consisting of metals, metal alloys, and metallurgical grade semiconductors, comprising the steps of: (a) texturing the substrate; (b) applying over the textured substrate an optically transparent, conducting metallurgical barrier layer; (c) continuously depositing over the barrier layer a first semiconductor layer of a first selected conductivity type by moving the substrate through a liquid saturated solution of a first semiconductor material dissolved in a solvent and applying a temperature gradient across the saturated solution to drive the growth of the first semiconductor layer; (d) continuously depositing a second semiconductor layer having a conductivity type opposite the first selected conductivity type by moving the substrate through an additional liquid saturated solution of a second semiconductor material dissolved in a solvent and applying a temperature gradient across the second saturated solution to drive the growth of the second semiconductor layer.
Claim 36
Independent Claim
166 words
A method of fabricating a thin film photovoltaic device on a substrate selected from a group consisting of metals, metal alloys, and metallurgical grade semiconductors, comprising the steps of: (a) texturing the substrate; (b) applying over the textured substrate an optical reflection metallurgical barrier layer having a predetermined depth to provide for enhanced reflection of light; (c) continuously depositing over the optical reflection barrier layer a first semiconductor layer of a first selected conductivity type by moving the substrate through a liquid saturated solution of a first semiconductor material dissolved in a solvent and applying a temperature gradient across the saturated solution to drive the growth of the first semiconductor layer; (d) continuously depositing a second semiconductor layer having a conductivity type opposite the first selected conductivity type by moving the substrate through an additional liquid saturated solution of a second semiconductor material dissolved in a solvent and applying a temperature gradient across the second saturated solution to drive the growth of the second semiconductor layer.
Claim 37
Independent Claim
166 words
A method of fabricating a thin film photovoltaic device on a substrate selected from a group consisting of metals, metal alloys, and metallurgical grade semiconductors, comprising the steps of: (a) texturing the substrate; (b) applying over the textured substrate an optical reflection metallurgical barrier layer having a predetermined depth to provide for enhanced reflection of light; (c) continuously depositing over the optical reflection barrier layer a first semiconductor layer of a first selected conductivity type by moving the substrate through a liquid saturated solution of a first semiconductor material dissolved in a solvent and applying a temperature gradient across the saturated solution to drive the growth of the first semiconductor layer; (d) continuously depositing a second semiconductor layer having a conductivity type opposite the first selected conductivity type by moving the substrate through an additional liquid saturated solution of a second semiconductor material dissolved in a solvent and applying a temperature gradient across the second saturated solution to drive the growth of the second semiconductor layer.
Claim 38
Independent Claim
132 words
A method of fabricating a thin film photovoltaic device on a substrate selected from a group consisting of metals, metal alloys, and metallurgical grade semiconductors, comprising the steps of: (a) texturing the substrate; (b) applying over the textured substrate an optically transparent, conducting metallurgical barrier layer; (c) continuously depositing over the optically transparent barrier layer a first semiconductor layer of a first selected conductivity type by moving the substrate through a liquid saturated solution of a first semiconductor material dissolved in a solvent and applying a temperature gradient across the saturated solution to drive the growth of the first semiconductor layer; (d) doping a layer of liquid saturated solution that remains on the deposited first semiconductor layer to provide a second semiconductor layer having conductivity type opposite to said first semiconductor layer.
Claim 39
Independent Claim
132 words
A method of fabricating a thin film photovoltaic device on a substrate selected from a group consisting of metals, metal alloys, and metallurgical grade semiconductors, comprising the steps of: (a) texturing the substrate; (b) applying over the textured substrate an optically transparent, conducting metallurgical barrier layer; (c) continuously depositing over the optically transparent barrier layer a first semiconductor layer of a first selected conductivity type by moving the substrate through a liquid saturated solution of a first semiconductor material dissolved in a solvent and applying a temperature gradient across the saturated solution to drive the growth of the first semiconductor layer; (d) doping a layer of liquid saturated solution that remains on the deposited first semiconductor layer to provide a second semiconductor layer having conductivity type opposite to said first semiconductor layer.
Claim 40
Dependent Claim
37 words
In the method of claims 33, 34, 35 or 32 wherein there is provided the further step of texture etching the surface of the second semiconductor layer to provide for light trapping of photons entering the device.
Claim 41
Dependent Claim
41 words
In the method of claims 33, 34, 35 or 32 wherein the first and second semiconductor layers are selected from the group consisting of silicon, copper sulfide, gallium arsenide, indium phosphide, zinc phosphide, cadmium telluride, zinc cadmium sulfide, and cadmium telluride.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 7.5 Years (Year 8) | 1995-10-18 | 1996-04-18 | 1996-10-18 | $3760.00 | Window Closed / Lapsed |
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