TCAD based numerical exploration of industrially feasible tunnel oxide passivated contact on p-type silicon

Abstract

Tunnel Oxide Passivated Contact (TOPCon) is considered as an immediate successor of Passivated Emitter and Rear Contact (PERC). Rear side full area hole selective passivating contact with front n+ diffused emitter on p-type silicon (Si) (p-TOPCon) would be an incremental upgrade from PERC. However, limited studies are present on p-type Si and most of them are on TOPCon with rear full area electron selective contact (n-TOPCon). In this work, we explore the potential of p-TOPCon by incorporating industry relevant material and process parameters in Sentaurus TCAD simulations. These include bulk lifetime (τb), wafer resistivity (ρ), polysilicon related rear parameters, front emitter sheet resistance (Rsheet) and its passivation (Sfront), and finger width (Wfinger). Simulation results are benchmarked against PERC and n-TOPCon. p-TOPCon outperforms PERC and has lower sensitivity to wider range of τb, ρ, and Sfront. Simulation suggests that an efficiency of 23.83% can be achieved for industrially feasible τb of 5 ms, ρ of 1 Ω-cm, emitter Rsheet of 132 Ω/sq, and Wfinger of 20μm for p-TOPCon. Replacement of diffused emitter with n-TOPCon would be ideal after accomplishing above anticipated advancements and in such a scenario, efficiency > 24.4% can be achieved on p-type Si.