Revised parametrization of the recombination velocity at SiO2/SiNx-passivated phosphorus-diffused surfaces

Abstract

We investigate the effective surface recombination velocity Seff of alkaline textured, Phosphorus-diffused and thermal SiO2/SiNx passivated surfaces with an emphasis on the impact of the thermal oxidation temperature. The application of a recent calibration procedure for the carrier lifetime measurements enables a precise determination of the dark saturation current density. The experimental results include 25 diffusion/oxidation process combinations that cover a wide range of final surface concentration levels Ns between 3⋅1020 cm−3 and 1⋅1019 cm−3, using oxidation temperatures Tox from 650 °C to 900 °C. This yields a data set that enables a revision of the commonly applied parameterization of the effective surface recombination velocity of this passivation scheme using numerical simulation. In addition, the impact of fixed surface charges is modeled for separating field effect and chemical passivation properties. Also, the role of the oxidation temperature on the passivation quality is investigated.