Abstract
In this experiment, the microstructure of the P-type polycrystalline silicon wafer was formed by acidic etching and the reflectivity was reduced, and the thickness of the antireflection layer was optimized. We used wet oxidation for growing an aluminum oxide film to form a PERC structure in solar cell fabrication. We found a best 125 nm thickness for the silicon nitride antireflection layer, which has a 0.3% lower average reflectance compared with the commercial wafer. It was also found that if the back side of the wafer has microstructure, it may affect the passivation effect of the aluminum oxide. The minority carrier lifetime would increase very little for the silicon wafer with microstructure on the back side and the resultant cell performance were degraded. However after using KOH solution to remove the backside microstructure, we found that the passivation layer of aluminum oxide rendered an increase in the minority carrier lifetime, and the cell performance could be improved.