Surface passivation of crystalline silicon by Cat-CVD amorphous and nanocrystalline thin silicon films C.Voz

In this work we study the electronic surface passivation of crystalline silicon with intrinsic thin silicon films deposited by Catalytic CVD. The contactless method used to determine the effective surface recombination velocity was the Quasi-Steady-State Photoconductance technique. Hydrogenated amorphous and nanocrystalline silicon films were evaluated as passivating layers on nand p-type float zone silicon wafers. The best results were obtained with amorphous silicon films which allowed effective surface recombination velocities as low as 60 and 130 cm s -1 on pand n-type silicon respectively. To our knowledge, these are the best results ever reported with intrinsic amorphous silicon films deposited by Catalytic CVD. The passivating properties of nanocrystalline silicon films strongly depend on the deposition conditions, specially on the filament temperature. Samples grown at lower filament temperatures (1600 oC) allowed effective surface recombination velocities of 450 and 600 cm s -1 on nand ptype silicon.