Extremely low surface recombination velocities on heavily doped planar and textured p+ silicon using low-temperature positively-charged PECVD SiOx/SiNx dielectric stacks with optimised antireflective properties

We present state-of-the-art results on boron emitter passivation (J_0e <; 25 fA/cm² and S_n0 <; 400 cm/s) with industrially fired positively-charged low-temperature PECVD SiO_x/SiN_x dielectric stacks deposited in an industrial reactor. These films feature a very low fixed charge density (~ + 6×10¹⁰ cm^-2) and excellent interface quality (D_{it, midgap} of ~3×10¹⁰ eV^-1 cm^-2) after an industrial firing step. Based on contactless corona-voltage measurements and device simulation, we explain the mechanism of surface passivation to be dominated by chemical passivation rather than field-effect passivation. With excellent optical and passivation properties, these films are suitable for high-efficiency cost-effective industrial n-type silicon wafer solar cells.