Interface engineering for the passivation of c-Si with O ₃-based atomic layer deposited AlO _x for solar cell application

We have investigated the effects of deposition temperature and post-annealing on the passivation performance of AlO _x films deposited by O ₃-based atomic layer deposition for crystalline Si. We found that the dramatic enhancement in the passivation performance of room-temperature deposited AlO _x films by post-annealing is due to the phase transformation of aluminum silicate to mullite in an AlO _x interlayer and the resulting self-aligned AlO _x/SiO _x interface. This result is interesting for the fabrication of high-performance silicon solar cells with AlO _x passivation layers.