Full Wafer Size IBC Cell with Polysilicon Passivating Contacts.

We investigate the application of polysilicon carrier-selective passivating contacts to IBC cells. We optimized the passivation of n-type and p-type polysilicon layers by managing the hydrogen supply to the interfacial oxide. Both surface passivation and firing stability were addressed. The best results so far are obtained for passivation capping layers that contain Al₂O₃ and SiN_x. For these passivated polysilicon layers, we present excellent J₀ and implied V∝ values on textured n-Cz wafers, with best values of < 1 fA/cm² and 741 mV for n-type, and 10 fA/cm² and 720 mV for p-type polysilicon, which are maintained after firing. The polysilicon layers were applied as carrier-selective passivating contacts for a full wafer size (156x156 mm²) IBC cell, using industrial compatible processes and commercially available n-type Cz wafers. The implied V∝ on the cell reaches 725 mV, which enables IBC cell efficiencies of 24%. After metallization, V∝ values of close to 700 mV were obtained. [ABSTRACT FROM AUTHOR]