TCAD Modeling of Interdigitated Back Contact Solar Cells with Hybrid Diffusion and Tunnel Oxide Passivated Contacts

The interdigitated back contact (IBC) silicon solar cells such as heterojunction with an intrinsic thin-film (HIT) and polycrystalline silicon on oxide (POLO) have both achieved a record power conversion efficiency (PCE) exceeding 26%. However, the complicated fabrication procedures and high cost currently hinder the deployment of these novel IBC solar cells in the photovoltaic market. Here, we investigate an n-type IBC solar cell architecture incorporating hybrid diffusion and tunnel oxide passivated contacts (TOPCon) to mitigate the fabrication complexity. A Sentaurus TCAD model which takes into account the tunneling mechanism of silicon oxides is developed and validated with a fabricated device. Subsequently, we investigate the impact of design parameters such as the anode/cathode ratio, the anode width with a fixed gap size, and the deviation of the laser contact openings. Based on the correlations between the design parameters and device characteristics, we can choose a practical device design. Finally, we demonstrate an IBC solar cell with a PCE of 20.3% fabricated with an improved metal contact process that lowers the contact resistivity.