Calibration of a stopping power model for silicon based on analysis of neutron depth profiling and secondary ion mass spectrometry measurements

Abstract

We measure the boron concentration versus depth profile within a silicon sample with four delta-doped planes by secondary ion mass spectrometry. In a neutron depth profiling (NDP) experiment, we illuminate the sample with a neutron beam. Nuclear reactions between the boron nuclei and neutrons produce alpha particles. Based on the measured boron concentration profile and models for the stopping power of the silicon sample, energy straggling, multiple scattering, and the observed energy resolution of the alpha particle detector, we predict the observed energy spectrum of the detected alpha particles. We predict the stopping power of silicon using the stopping and range of ions in matter code SRIM-2000. The predicted locations of the NDP energy peaks are consistently at lower energies than the locations of the observed peaks. This discrepancy is consistent with the claim that SRIM-2000 overestimates the actual stopping power of silicon. Empirically, we estimate a stopping power reduction factor to be 5.06%±1.06%. When we reduce the SRIM-2000 prediction by this factor, we get good agreement between the observed and predicted NDP measurements.