Analysis of Processing Steps for Industrial Large Area n-Type Solar Cells with Screen Printed Aluminum-Alloyed Rear Emitter and Selective FSF

26th European Photovoltaic Solar Energy Conference and Exhibition; 1160-1163
Applying the standard process for p-type solar cells to n-type silicon results in a “PhosTop” solar cell with a screen printed alloyed aluminum emitter on the rear side [1]. This cell concept can be improved by adding a selective FSF and a SiO2/PECVD SiNx stack passivation layer, resulting in a highest confirmed stable efficiency of 19.4 % for 6” n-type Cz-Si solar cells [2]. Besides a very low front SRV, this cell concept also demands for a very high bulk lifetime. We therefore analyze the change of bulk lifetime and conductivity after each high temperature process step in the applied cell process. Furthermore we investigate the current generation from the unprinted wafer edge with no emitter.