Trajectory-dependent electronic stopping in simulations of self-ion ranges in elemental semiconductors

Abstract

Characterizing how materials respond to energetic-particle irradiation is fundamental to a wide range of semiconductor processes. However, the deceleration of energetic particles in solids remains an active area of research due to the complex nature of energy exchange between ionic and electronic systems. Recently, the advent of two-temperature molecular dynamics models has enabled more realistic simulations of this highly anisotropic deceleration process. In this work, we present a parametrization of the unified two-temperature model for self-ions in elemental semiconductor crystals that accurately reproduces the electronic stopping values obtained from real-time time-dependent density functional theory (rt-TDDFT). This includes channeled and incommensurate trajectories, as well as collision-like interactions. Using this model, we obtain ion range profiles that closely match available experimental data. We present penetration profiles for principal channeling directions and random trajectories. In the process, we characterize rt-TDDFT electronic stopping in germanium and diamond and extend existing results for silicon.