Annealing induced amorphous/crystalline silicon interface passivation by hydrogen atom diffusion

Post-annealing is an efficient method to improve passivation quality of the amorphous/crystalline silicon configuration and it’s been widely used in fabrication of amorphous/crystalline silicon heterojunction solar cells. In this study, hydrogenated amorphous silicon thin films are deposited on n type monocrystalline silicon, using a single chamber radio-frequency plasma-enhanced chemical vapor deposition system. After passivation the best result with effective minority carrier lifetime (τeff) exceeding 1600 μs is achieved. Fourier transform infrared spectrum is utilized to investigate the structure evolution after annealing. The result shows that, the improved passivation quality is attributed to interface dangling bonds saturated by H atoms diffusion during annealing, the reason of passivation quality affected by annealing and film thickness is also proposed.