Plasma-Enhanced Chemical-Vapor-Deposited SiO_x(N_y)/n-type Polysilicon-on-Oxide-Passivating Contacts in Industrial Back-Contact Si Solar Cells

In this article, different in situ grown plasma-enhanced chemical vapor deposition (PECVD)-grown interfacial oxides for n-type polysilicon-passivating contacts are investigated. Herein, SiO_x(N_y)/n-type amorphous silicon stacks created from either N₂O plasma or O₂ plasma are applied to POLy-silicon on Oxide interdigitated back-contact (POLO IBC) solar cells using the structured deposition process through a glass mask to create the IBC layout. The impact of plasma exposure time for interfacial oxide growth on solar cell efficiencies is experimentally determined. In the POLO IBC cell results, it is shown that the PECVD oxides SiO_xN_y and SiO_x with optimized plasma exposure time give similar maximum efficiencies of 23.8% and 23.7%, respectively. In these data, the feasibility to deposit a high-quality in situ PECVD interfacial SiO_x(N_y) layers for surface passivation and current transport of passivated contacts at the same time is demonstrated. For the SiO_x/n-type polysilicon stack, it is found that both plasma exposure time for interfacial oxide growth and polysilicon anneal temperature variations can lead to similar optimum of solar cell efficiencies. The current open-circuit voltage losses due to metallization for the solar cells are analyzed and a realistic efficiency of 25.22% is calculated to achieve optimized POLO IBC solar cells applying the synergistic efficiency gain analysis on Quokka3 simulations.