Simulation of pulse height spectra in ion beam induced charge microscopy of polycrystalline silicon

This article describes computer simulations of the charge pulse height spectra that are obtained by irradiating selected regions of a polycrystalline silicon solar cell by a 2 MeV He+microbeam. The spectra are calculated in terms of the energy loss function of the ions and the distribution of the charge collection probability at a grain boundary, and illustrate the effect of the interface recombination velocity of the grain boundary and the bulk diffusion length. The simulations are compared with some experimental spectra to demonstrate the applicability of the theory. The method can be extended to the analysis of other semiconductor defects or more complex devices.