Influence of the initial transient state of plasma and hydrogen pre-treatment on the interface properties of a silicon heterojunction fabricated by PECVD

Amorphous/crystalline silicon heterojunctions (a-Si:H/c-Si SHJ) were prepared by plasma-enhanced chemical vapor deposition (PECVD). The influence of the initial transient state of the plasma and the hydrogen pre-treatment on the interfacial properties of the heterojunctions was studied. Experimental results indicate that: (1) The instability of plasma in the initial stage will damage the surface of c-Si. Using a shutter to shield the substrate for 100 s from the starting discharge can prevent the influence of the instable plasma process on the Si surface and also the interface between a-Si and c-Si. (2) The effect of hydrogen pre-treatment on interfacial passivation is constrained by the extent of hydrogen plasma bombardment and the optimal time for hydrogen pre-treatment is about 60 s.