Improvements in Cz Silicon PV Module Manufacturing

Work focused on reducing the cost per watt of Cz Si photovoltaic modules under Phase I of Siemens Solar Industries; DOE/NREL PVMaT 4A subcontract is described. Module cost components are analyzed and solutions to high-cost items are discussed in terms of specific module designs. The approaches of using larger cells and modules to reduce per-part processing cost, and of minimizing yield loss areparticularly leveraging. Yield components for various parts of the fabrication process and various types of defets are shown, and measurements of the force required to break wafers throughout the cell fabrication sequence are given. The most significant type of yield loss is mechanical breakage. The implementation of statistical process control on key manufacturing processes at Siemens SolarIndustries is describe. Module configurations prototyped during Phase I of this project and scheduled to begin production in Phase II have a projected cost per watt reduction of 19%.