Process for RF sputtering of cadmium telluride photovoltaic cell

Abstract

A thin film photovoltaic cell having a semiconductor layer of cadmium sulfide and a semiconductor layer of cadmium telluride is manufactured in a process in which the cadmium sulfide and the cadmium telluride are deposited onto a conductive layer of a substrate by RF sputtering. A layer of cadmium sulfide is deposited on the conducting layer of the substrate by RF magnetron sputtering. After the cadmium sulfide is deposited, a layer of cadmium telluride is deposited by RF magnetron sputtering. The RF sputtering deposition of the two semiconductor layers increases the efficiency of the cell and is conducive to a large scale manufacturing process. The photovoltaic cell may include only two semiconductor layers forming a p-n junction. A third semiconductor layer, typically zinc telluride, may be added to the cell to form a p-i-n junction. The efficiency of the cell is further increased by treatment with cadmium chloride and annealing in dry air. The cadmium chloride is deposited using laser-driven physical vapor deposition. The cell is then annealed at approximately 400 degrees Celsius in air prior to deposition of the second contact. The second contact is deposited using vacuum evaporation of copper and gold.

Dependencies are inferred from the claim text.