Study of Al2O3/ZnO multilayers for silicon surface passivation

A good surface passivation of p-type si surface is achieved by Al2O3/ZnO multilayers deposited using atomic layer deposition. The effective surface recombination velocity (S-eff) less than 20cm/s is realized with symmetrically deposited multi-layers on p-Si. In the process a single supercycle consists of one al2o3 and 15 zno layers that can be repeated to get desired thickness of the stack. Subsequently, the samples are annealed in hydrogen ambient at different temperatures ranging from 350 to 500 degrees C for different time duration starting from 15 to 120 min. The best S-eff (< 20cm/s) is achieved for samples annealed in H-2 at 450 degrees C for 45min. If this order of passivation is realized at cell level, an improvement in implied open circuit voltage change of 70mv is expected.