SiO2/SiNx stacking layer for rear surface passivation of PERC

We investigated to apply thermal SiO₂/APCVD SiO₂/PECVD SiNx stacking layer to the rear surface passivation of PERC. After rough optimization of process conditions of LCO and firing steps, the cell efficiency reached 19.3% and it was 1.1% absolute higher than that of the conventional cell. The results of CV measurements suggest that the hydrogen released from the PECVD SiNx during the firing reduces Dit and the deposition of SiO₂ by APCVD is effective to reduce Qf. By combining these two effects, both Dit and Qf of the thermal SiO₂/APCVD SiO₂/PECVD SiNx stacking layer are largely reduced. Therefore, the thermal SiO₂/APCVD SiO₂/PECVD SiNx stacking layer is suitable for rear surface passivation of PERC.