Theoretical study on the influence of photon reabsorption on spatially resolved photocarrier radiometric imaging of silicon wafers

摘要

The influence of reabsorption of spontaneously emitted photons within silicon wafers on spatially resolved steady-state photocarrier radiometric (PCR) imaging is theoretically analyzed. A new PCR model with photon reabsorption, in which both band-to-band absorption and free carrier absorption are taken into account, is introduced. It is shown that the influences strongly depend on both the excess carrier density and its distribution, which are sensitive to the doping level, electronic transport properties, sample thickness, and surface topography. If photon reabsorption is ignored in the determination of the electronic transport parameters for high-doping double polished silicon wafers via multi-parameter fitting, the relative errors of the fitted minority carrier lifetime, diffusion coefficient, and front surface recombination velocity could reach 38%, 9.5%, and 24%, respectively.