Investigation on the impact of metallic surface contaminations on minority carrier lifetime of a-Si:H passivated crystalline silicon

Simple two-step wet-chemical cleans composed of an oxidizing step with in water dissolved ozone (DIO3) followed by an etching step have been studied for high-efficient hetero-junction silicon solar cell applications. For this purpose textured FZ-Si samples passivated with amorphous silicon were investigated. Especially the effect of metal contaminations located at the crystalline silicon surface on minority carrier lifetime was examined. A relation between minority carrier lifetime and Ca, Cr and Fe as metallic surface contaminations is shown. The results will be compared with those of standard cleaning concepts using different oxidizing solutions such as HCl / H 2O2 and NH4OH / H2O2.