Wet-Chemical Preparation of Silicon Tunnel Oxides for Transparent Passivated Contacts in Crystalline Silicon Solar Cells

Transparent passivated contacts (TPCs) using a wide band gap microcrystalline silicon carbide (μc-SiC:H­(n)), silicon tunnel oxide (SiO₂) stack are an alternative to amorphous silicon-based contacts for the front side of silicon heterojunction solar cells. In a systematic study of the μc-SiC:H­(n)/SiO₂/c-Si contact, we investigated selected wet-chemical oxidation methods for the formation of ultrathin SiO₂, in order to passivate the silicon surface while ensuring a low contact resistivity. By tuning the SiO₂ properties, implied open-circuit voltages of 714 mV and contact resistivities of 32 mΩ cm² were achieved using μc-SiC:H­(n)/SiO₂/c-Si as transparent passivated contacts