Optoelectrical properties of high-performance low-pressure chemical vapor deposited phosphorus-doped polysilicon layers for passivating contact solar cells

Abstract

We examine the optical behavior and electrical performance of ultra-thin interfacial oxide (iOx) and polysilicon (poly-Si) layers deposited using industrial tube-type low-pressure chemical vapor deposition (LPCVD). The intrinsic and doped poly-Si layers of different thicknesses are examined for their optical, electrical and passivation properties at different conditions. We present an outstanding surface passivation result with in-situ iOx and n+doped poly-Si layers of thickness ranging from 150 nm to 250 nm. Intrinsic poly-Si layers are deposited using LPCVD and doped at high temperature in a tube furnace. An excellent effective minority carrier lifetime of 17 ms, implied open-circuit voltage of 747 mV and an ultralow dark saturation current density of 1.2 fA/cm2 are obtained for a 150 nm thick n+ poly-Si after fast-firing at a peak temperature of 745 °C.