Selective emitters in Si by single step rapid thermal diffusion for photovoltaic devices

摘要

Selective phosphorous diffusion is performed in Si to simultaneously form shallow n/sup +/p junctions of different depths in the submicron range by rapid thermal annealing (RTA). Low temperature (400/spl deg/C) atmospheric pressure chemical vapor deposited (APCVD) phosphosilicate glass (PSG) is used as diffusion source. A wide range of n/sup +/p junctions could be tailored with the same thermal budget by changing only the APCVD-PSG composition. This allows the formation of selectively diffused emitters in different regions of the wafer in one RTA step. 10 cm/spl times/10 cm Cz-Si selective emitter photovoltaic (PV) devices are fabricated this way with high energy conversion efficiencies in the range of 17% to 18%.