Atomistic simulation of displacement damage and effective nonionizing energy loss in InAs

Abstract

A molecular dynamics (MD) method, along with the analytical bond-order potential, is applied to study defect production in InAs. This potential is modified to obtain a better description for point-defect properties and is extended for proper applications in radiation damage simulation. By using this modified potential, the threshold displacement energy $({E}_{d})$, as one of the crucial parameters in radiation damage studies, is calculated over thousands of crystallographic directions for incorporating spatial anisotropy. However, the ${E}_{d}$ dependence on directions is found to be relatively weak. The defect production, clustering, and evolution in InAs are further investigated for the energies of the primary knock-on atom (PKA) ranging from 500 eV to 40 keV. A nonlinear defect production is seen with increasing PKA energy. This nonlinearity, which is associated with the direct-impact amorphization, is very distinctive for PKA energies ranging from 1 to 20 keV. Based on the damage density evaluated from molecular dynamics simulations, a theoretical model is developed for determining nonionizing energy loss (NIEL), which can be used for quantifying the electronic device degradation in a space radiation environment. The NIELs of InAs for proton, alpha, and Xe particles are calculated from the displacement threshold up to 60 MeV in comparison with available data so as to validate our model in the current study.