Surface damage and metal-catalyzed chemical etching investigation of multicrystalline silicon by diamond wire sawing

摘要

Cutting silicon ingots into silicon wafer is a crucial step in solar cell production process. As a major cutting technique, diamond wire sawing (DWS) has already completely replaced the multi-wire slurry sawing (MWSS). In this work, the essential features of diamond wire cut multicrystalline silicon wafer, behavior of surface damage, formation mechanism, removal of damage layer, and influence of damage layer on making texture surface and performance of solar cells were investigated. Amorphous layer and defects layer are found on the surface of DWS wafer, which restricts the process of making texture. By using metal-catalyzed chemical etching (MCCE) method to make texture surface, the etching rate is faster without damage layer than with damage layer, and the reflectivity can be reduced from 19.08% to 14.79%. After removing the damage layer, the conversion efficiency of solar cell is 17.29%, which is 2.35% higher than that of the cell with the damage layer.