Extremely low surface recombination velocities on low-resistivity n-type and p-type crystalline silicon using dynamically deposited remote plasma silicon nitride films

摘要

Extremely low upper-limit effective surface recombination velocities (S_(eff.max)) of 5.6 and 7.4 cm/s, respectively, are obtained on ~1.5Ωcm n-type and p-type silicon wafers, using silicon nitride (SiN_x) films dynamically deposited in an industrial inline plasma-enhanced chemical vapour deposition (PECVD) reactor. SiN_x films with optimised antireflective properties in air provide an excellent S_(eff.max) of 9.5 cm/s after high-temperature (>800 ℃) industrial firing. Such low S_(eff.max) values were previously only attainable for SiN_x films deposited statically in laboratory reactors or after optimised annealing; however, in our case, the SiN_x films were dynamically deposited onto large-area c-Si wafers using a fully industrial reactor and provide excellent surface passivation results both in the as-deposited condition and after industrial-firing, which is a widely used process in the photovoltaic industry. Contactless corona-voltage measurements reveal that these SiN_x films contain a relatively high positive charge of (4-8) x 10~(12)cm~(-2) combined with a relatively low interface defect density of ~5 x 10~(11) eV~(-1) cm~(-2).