The influence of temperature and energy on defect evolution and clustering during cascade in GaAs

Abstract

Molecular dynamics (MD) is used to simulate cascade collision in gallium arsenide (GaAs) under different temperatures (300–900 K). During the entire simulation, the primary knock-on atom (PKA) is incident at a special angle, and its energy (EPKA) is within 10 keV. The simulation results are found to be reasonable based on the NRT equation and show that high EPKA causes direct damage, thereby increasing all evolution parameters such as the peak time (tp), steady time (ts), peak (Np) number, and steady (Ns) number of defects. Compared to EPKA, high temperatures reduce Ns of Frenkel pairs and increase the threshold displacement energy (Ed), during which Ga defects occupy the main part. It is also found that the difference between Ga and As vacancy-interstitial pairs on the amount makes tp of GaAs defects longer than AsGa defects, leading to a significant delay in antisite defects as temperature increases. Regarding clusters, high temperatures can promote the transformation of large clusters to isolated point defects for the vacancies, while only the transformation of large and small clusters is observed in the interstitials.