Passivation and Microstructure of Dual Intrinsic a-Si:H Layers for SHJ Solar Cells

We demonstrate a high passivation quality of dual a-Si:H(i) layers with excellent implied open circuit voltage values and a beneficial influence by an intermediate H2 plasma treatment made with an industrial inline PECVD tool from Meyer Burger Germany with radio frequency plasma sources (MAiA tool). Furthermore, the correlation between the gas flow ratio of hydrogen to silane during PECV deposition and the microstructure of the a-Si:H(i) layers represented by the relative bonding density of monohydrides (Si-H) and dihydrides (Si-H2) obtained by ATR-FTIR analysis is shown. Also the positive impact of an intermediate H2 plasma treatment is illustrated. Finally the resulting passivation quality reached by the use of dual a-Si:H(i) layers is depicted, which enables a significant improvement of the implied open-circuit voltage compared to the single layers, especially in the case of a-Si:H(i/p) layer stacks.