Minority-carrier trapping in Ga-doped multicrystalline Si wafers

B- and Ga-doped multicrystalline-silicon (mc-Si) wafers with different resistivity and different positions of grown ingots have been used to evaluate the stability, quality improvement and thermal annealing effects on carrier lifetimes. The effective carrier lifetimes are improved and high lifetimes as high as 200 μs are realized after P-diffusion and SiNx coating. Ga-doped wafers show a certain stability after thermal annealing up to 250 °C which insures the possibilities of eliminating the light-induced degradation effects generated in p-type mc-Si wafers.