A novel analysis method to determine the surface recombination velocities on unequally passivated surfaces of a silicon wafer by the short wavelength spectrum excited quasi-steady-state photoconductance measurement

In this work, we propose an analysis approach to determine the individual surface recombination velocities (S-1 and S-2) on each surface of an unequally passivated wafer, which precludes the crude assumption of S-1 = S-2 in conventional methods. Taking advantage of the surface distributed excess charge carriers relatively sensitive to the surface recombination, we probe the sample using quasi-steady-state illumination of the xenon flash lamp equipped with a short pass filter (FSP1). A set of samples passivated by SiO2 and SiNx, as well as bare silicon wafers, are prepared in the experiment. On the basis of fitting the measured time-dependent-excess charge carriers, S-1 and S-2 are determined based on our analysis approach. The spatial and the temporal distributions of excess charge carrier density are presented. The dependence of tau(eff) on the wavelength, S and tau(bulk) is also discussed in detail. The reliability of this method is finally verified with a long pass filter (FLP2). (C) 2018 Author(s).