Surface recombination velocity of phosphorus-diffused silicon solar cell emitters passivated with plasma enhanced chemical vapor deposited silicon nitride and thermal silicon oxide

The emitter saturation current density (J(Oe)) and surface recombination ve locity (S-p) of various high quality passivation schemes on phosphorus-diff used solar cell emitters have been determined and compared. The passivation schemes investigated were (i) stoichiometric plasma enhanced chemical vapo r deposited (PECVD) silicon nitride (SiN), (ii) forming gas annealed therma lly grown silicon oxide, and (iii) aluminum annealed (alnealed) thermal sil icon oxide. Emitters with sheet resistances ranging from 30 to 430 and 50 t o 380 Omega/square were investigated for planar and random-pyramid textured silicon surfaces, which covers both industrial and laboratory emitters. Th e electronic surface passivation quality provided by PECVD SiN films was fo und to be good, with S-p values ranging from 1400 to 25 000 cm/s for planar emitters. Thin thermal silicon oxides were found to provide superior passi vation to PECVD SiN, with the best passivation provided by an alnealed thin oxide (S-p values between 250 and 21 000 cm/s). The optimized PECVD SiN fi lms are, nevertheless, sufficiently good for most silicon solar cell applic ations. (C) 2001 American Institute of Physics.