Defect termination on crystalline silicon surfaces by hydrogen for improvement in the passivation quality of catalytic chemical vapor-deposited SiN_x and SiN_x/P catalytic-doped layers

We investigate the role of hydrogen (H) in the improvement in the passivation quality of silicon nitride (SiN_x) prepared by catalytic chemical vapor deposition (Cat-CVD) and Cat-CVD SiN_x/phosphorus (P) Cat-doped layers on crystalline silicon (c-Si) by annealing. Both structures show promising passivation capabilities for c-Si with extremely low surface recombination velocity (SRV) on n-type c-Si. Defect termination by H is evaluated on the basis of defect density (N_d) determined by electron spin resonance (ESR) spectroscopy and interface state density (D_) calculated by the Terman method. The two parameters are found to be drastically decreased by annealing after SiN_x deposition. The calculated average D_ at midgap (D_) is 2.2×10^ eV^cm^ for the SiN_x/P Cat-doped c-Si sample with a SRV of 2 cm/s, which is equivalent to 3.1×10^ eV^cm^ for the SiN_x/c-Si sample with a SRV of 5 cm/s after annealing. The results indicate that H atoms play a critical role in the reduction in D_ for SiN_x/c-Si and SiN_x/P Cat-doped c-Si, resulting in a drastic reduction in SRV by annealing