Impurity diffusion effect on p/i interface properties of p-i-n junction microcrystalline silicon solar cells

Intrinsic microcrystalline silicon (/spl mu/c-Si:H) grown by SiH/sub 4/-H/sub 2/ plasma at different growth temperatures have been applied to superstrate-type p-i-n solar cells in order to investigate effect of i-layer growth temperature (T/sub s/) on p/i interface properties. Although high quality /spl mu/c-Si:H films (low defect density and large grain size) are obtained at T/sub s//spl sim/250/spl deg/C, short circuit current and fill factor decrease markedly with increasing T/sub s/ (>200/spl deg/C) accompanied with the strong voltage-dependent charge collection behavior in blue response. Impurity depth profile and photoluminescence studies reveal that appreciable boron diffusion occurs during i-layer growth when T/sub s/>200/spl deg/C, which creates non-radiative recombination centers at p/i interface. These results reasonably account for the low-temperature window of i-layer growth in /spl mu/c-Si:H p-i-n solar cell fabrication.