The invention relates to a high-efficiency selective emitter
solar cell diffusion process. The high-efficiency selective emitter
solar cell diffusion process comprises the steps of: boat feeding, temperature rise, constant temperature, oxidization, deposition 1, propulsion 1, deposition 2, propulsion 2, oxidation, deposition 3, temperature rise, temperature reduction, deposition 4, temperature reduction and boat taking. According to the invention, high-temperature post-oxidation is added in the process, after the deposition step at the low temperature is finished, the temperature rises continuously and is kept at a certain high-temperature condition, on this basis, a
phosphorus source is activated, and then the temperature reduction, oxidization and deposition are performed to perform richphosphorus gettering, the improved steps can effectively enable the
phosphorus source in the formed PSG to be continuously distributed into a
silicon substrate, and in addition, the PSG is enriched with a large amount of effective
phosphorus sources. The improvement of the process ensures that the non-
laser region keeps a low
surface concentration after
diffusion, and the
laser heavily doped region has a
high surface concentration, thereby effectively solving the problem of compatibility of the low
surface concentration of the non-
laser region and the
high surface concentration of the laser heavily doped region; the homogeneity of
sheet resistance is obviously improved after diffusion through the improvement of the process; and the
sheet resistance of the laser heavily doped region is lower, and the metallization contact is better.