System and method for eliminating short circuit current paths in photovoltaic devices
First Claim
1. In a process of making a photovoltaic device of the type including a semiconductor region overlying an elongated conductive substrate and a layer of conductive light transmissive material overlying said semiconductor region, a method of eliminating a short circuit current path extending from said substrate through said semiconductor region to said conductive light transmissive material, comprising applying a thin layer of an electrolyte solution to said conductive light transmissive material in the area of said short circuit current path and passing a current through said short circuit current path and said electrolyte for removing said conductive light transmissive material from contact with said short circuit current path.
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Accused Products
Abstract
Systems and methods for detecting and eliminating short circuit current paths through photovoltaic devices of the type including at least one semiconductor region overlying a substrate and a layer of conductive light transmissive material overlying the at least one semiconductor region are disclosed. The short circuit current paths which are eliminated extend through the at least one semiconductor region from the substrate to the layer of conductive light transmissive material. The resistivity of the short circuit current path is increased substantially at the interface between the conductive light transmissive material and the semiconductor region by isolating electrically the conductive light transmissive material from the short circuit current path.
The isolation can be provided by removing the transparent conductive material from electrical contact or connection with the short circuit current path. The isolation also can be provided by depositing a body of insulating material onto the semiconductor region over an area including a short circuit current path prior to the deposition of the conductive light transmissive material. Further, the short circuit current path can be detected and located by applying a voltage to discrete areas of the device through a conductive solution which path then can be eliminated as described above.
49 Citations
32 Claims
- 1. In a process of making a photovoltaic device of the type including a semiconductor region overlying an elongated conductive substrate and a layer of conductive light transmissive material overlying said semiconductor region, a method of eliminating a short circuit current path extending from said substrate through said semiconductor region to said conductive light transmissive material, comprising applying a thin layer of an electrolyte solution to said conductive light transmissive material in the area of said short circuit current path and passing a current through said short circuit current path and said electrolyte for removing said conductive light transmissive material from contact with said short circuit current path.
- 7. In a process of making a photovoltaic device of the type including a semiconductor region overlying a conductive surface of a substrate and a layer of conductive light transmissive material overlying said semiconductor region, a method of eliminating a short circuit current path extending from said conductive surface through said semiconductor region to said conductive light transmissive material, comprising the steps of locating said short circuit current path and thereafter increasing substantially the resistivity of said short circuit current path selectively at the interface between said conductive light transmissive material and said semiconductor region.
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12. In a process of making photovoltaic devices of the type including at least one active semiconductor region overlying a conductive substrate and layer of conductive transparent material overlying said at least one active region, a method of eliminating short circuit current paths through said at least one active region to said layer of transparent conductive material, comprising the steps of:
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detecting the location of said short circuit current paths; and
thereafterisolating said short circuit current paths electrically from said transparent conduction material. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. In a process of making photovoltaic devices of the type including at least one active semiconductor region overlying a conductive substrate and a layer of conductive transparent material overlying said at least one active region, a method of eliminating short circuit current paths from said substrate, through said at least one active region, and to said layer of transparent conductive material comprising the steps of:
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applying a voltage to said device between discrete areas of said substrate and said transparent conductive layer, said voltage being less than the forward conduction bias voltage of said device; detecting when the current through the device is above a predetermined limit for locating the short circuit current paths through the device; and removing the transparent conductive material from said at least one active region in the discrete areas corresponding to the detected short circuit current paths for electrically isolating said transparent conductive material from said short circuit current paths. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
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Specification