Progress In P-Type Tunnel Oxide-Passivated Contact Solar Cells With Screen-Printed Contacts

Herein, an update on the work on high-efficiency p-type solar cells with p-type-passivating rear contacts formed by low-pressure chemical vapor deposition and screen-printed contacts is given. It is shown that thin polysilicon layers enable a high level of surface passivation but do show increased contact resistivity and especially contact recombination. Commercially available pastes and dependence of contact resistivity and contact recombination on polylayer thickness and firing set temperature are investigated. For 240 nm-thick poly-Si layers, the values down to 4 m omega cm(2) and 60 fA cm(-2) are observed. For the presented process sequence, improved hydrogenation as one possibility to increase the passivation quality of the passivating contact structure is identified. Implementing all findings into a final solar cell, a maximum total area conversion efficiency of 21.2% is reported.