Improved contact metallization for high efficiency EFG polycrystalline silicon solar cells

Improvements in the performance of polycrystalline silicon solar cells based on a novel, laser-patterned contact process are described. Small lots of cells having an average conversion efficiency of 14+%, with several cells approaching 15%, are reported for cells of 45 cm/sup 2/ area. The high-efficiency contact design is based on YAG laser patterning of the silicon nitride antireflection (AR) coating. The Cu metallization is done using light-induced plating, with the cell providing the driving voltage for the plating process. The Cu electrodeposits into the laser-defined windows in the AR coating for reduced contact area, after which it bridges on top of the Ar coating to form a continuous finger pattern. The higher cell conversion efficiency is attributed to reduced shadow loss, higher junction quality, and reduced metal-semiconductor interfacial area.<
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