19.9 % efficient bifacial n-type solar cell produced by co-diffusion-cobin

We present co-diffused bifacial n-type solar cells (CoBiN) with peak efficiencies of 19.9 %. The codiffusion process is based on a high temperature step in an atmosphere containing POCl3 and a BSG/SiOx layer stack deposited by atmospheric pressure chemical vapor deposition. Secondary ion mass spectroscopy measurements show that the reaction of POCl3 with the SiOx layer results in the formation of a PSG layer converting a fraction of the SiOx layer. Electrochemical capacitance voltage measurements do not detect an influence of POCl3 on the boron emitter.