Accurate electronic transport characterization of B+ ion-implanted silicon wafers with self-normalized nonlinear photocarrier radiometry

Abstract A self-normalized photocarrier radiometry (PCR) is proposed to characterize the electronic transport properties (minority carrier lifetime, carrier diffusion coefficient, and surface recombination velocity) of B+ ion-implanted silicon wafers via multi-parameter estimation. In self-normalized PCR the amplitude and phase measured from the implanted surface are normalized by that measured from the matte rear surface (non-implanted substrate) of the ion-implanted silicon wafer to eliminate the need to measure the instrumental frequency response which is a major error source of the multi-parameter estimation. Two- and single-layer nonlinear PCR models are employed respectively to describe the PCR signals measured from the implanted and matte rear surfaces of the wafers. The self-normalized PCR is applied to the simultaneous determination of the electronic transport parameters and the thickness of the implanted layer of the ion-implanted silicon wafers. Experimentally, the frequency dependences of PCR amplitude and phase measured from the implanted and rear surfaces under 830-nm excitation at 40.5 mW are measured for seven B+ ion-implanted silicon wafers with different implantation doses. The electronic transport parameters and thicknesses of the implanted layers are then determined by multi-parameter fitting the self-normalized PCR amplitude and phase to corresponding nonlinear PCR models, as well as determined by the conventional PCR via measuring the instrumental frequency response and subtracting its influence on the measured PCR signals of the ion-implanted wafers for comparison. The lower variances of multi-parameter fitting and improved uncertainties of the fitted transport parameters in the self-normalized PCR as compared to that in the conventional PCR corroborate the improved accuracy and reliability of the self-normalized PCR for the simultaneous determination of the electronic transport parameters of ion-implanted silicon wafers.