I. Introduction
Using stack layers of Al SiN passivation of boron doped back surface fields (BSF) is known to achieve low values of dark saturation current densities fA/cm 2 at a sheet resistance in the range sq sq [1], [2]. Such well passivated BSF-structures have been successfully implemented in solar cell processes to fabricate passivated emitter and rear totally diffused (PERT) solar cells [1], [2] from p-type wafers with only minor changes compared to a passivated emitter and rear cell (PERC) process. In this paper, we investigate the efficiency potential of these PERT solar cells compared PERC solar cells with focus on the influence of the bulk wafer resistivity.