Zinc oxide film method and structure for CIGS cell
First Claim
1. A method for fabricating a thin film of zinc oxide for a photovoltaic device comprising:
- providing a substrate having an absorber layer and an overlying window layer;
loading the substrate into a chamber;
subjecting the substrate to a vacuum environment ranging from 0.1 Torr to about 0.02 Torr while maintaining it at a temperature of between about 130 degrees Celsius to about 190 degrees Celsius;
introducing a mixture of reactant species derived from diethylzinc species, water species, and a carrier gas;
introducing a diborane species using a flow rate of less than five percent of the diethylzinc species into the mixture of reactant species;
forming a zinc oxide film overlying the window layer to define a transparent conductive zinc oxide having a resistivity of less than about 2.5 milliohm-cm and an average grain size between about 3000 Angstroms and about 5000 Angstroms.
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Abstract
A method for fabricating a thin film photovoltaic device. The method includes providing a substrate comprising an absorber layer and an overlying window layer. The substrate is loaded into a chamber and subjected to a vacuum environment. The vacuum environment is at a pressure ranging from 0.1 Torr to about 0.02 Torr. In a specific embodiment, a mixture of reactant species derived from diethylzinc species, water species and a carrier gas is introduced into the chamber. The method further introduces a diborane species using a selected flow rate into the mixture of reactant species. A zinc oxide film is formed overlying the window layer to define a transparent conductive oxide using the selected flow rate to provide a resistivity of about 2.5 milliohm-cm and less and an average grain size of about 3000 to 5000 Angstroms.
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Citations
21 Claims
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1. A method for fabricating a thin film of zinc oxide for a photovoltaic device comprising:
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providing a substrate having an absorber layer and an overlying window layer; loading the substrate into a chamber; subjecting the substrate to a vacuum environment ranging from 0.1 Torr to about 0.02 Torr while maintaining it at a temperature of between about 130 degrees Celsius to about 190 degrees Celsius; introducing a mixture of reactant species derived from diethylzinc species, water species, and a carrier gas; introducing a diborane species using a flow rate of less than five percent of the diethylzinc species into the mixture of reactant species; forming a zinc oxide film overlying the window layer to define a transparent conductive zinc oxide having a resistivity of less than about 2.5 milliohm-cm and an average grain size between about 3000 Angstroms and about 5000 Angstroms. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for forming a thin film photovoltaic device comprising:
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providing a substrate having a surface region; forming a first electrode layer overlying the surface region; forming an absorber material comprising a copper species, an indium species, and a selenide species overlying the first electrode layer; forming a window layer comprising a cadmium selenide species overlying the absorber material; subjecting the substrate to a vacuum environment ranging from 0.1 Torr to about 0.02 Torr; and forming a zinc oxide layer characterized by grain size ranging from about 3000 Angstroms to about 5000 Angstroms overlying the window layer using precursor gases including a zinc species, an oxygen species, and a carrier gas including at least a nitrogen species at a temperature greater than about 200 degrees Celsius to form a transparent zinc oxide layer having a resistivity of less than about 2.5 milliohm-cm. - View Dependent Claims (18, 19, 20, 21)
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Specification