Title :
Quantum Mechanical Description of Displacement Damage Formation
Author :
Beck, M.J. ; Hatcher, R. ; Schrimpf, R.D. ; Fleetwood, D.M. ; Pantelides, S.T.
Author_Institution :
Dept. of Phys. & Astron., Vanderbilt Univ., Nashville, TN
Abstract :
Atomic-scale processes during displacement damage formation have been previously studied using molecular dynamics (MD) calculations and empirical potentials. Low-energy displacements (1 keV) are characterized by a high cross-section for producing secondary knock-on atoms and damage clusters, and determine the threshold displacement energy (an important parameter in NIEL calculations). Here we report first-principles, parameter-free quantum mechanical calculations of the dynamics of low-energy displacement damage events. We find that isolated defects formed by direct displacements result from damage events of les100 eV. For higher energy events, the initial defect profile, which subsequently undergoes thermal annealing to give rise to a final stable defect profile, is the result of the relaxation and recrystallization of an appreciable volume of significantly disordered and locally heated crystal surrounding the primary knock-on atom displacement trajectory.
Keywords :
annealing; density functional theory; molecular dynamics method; radiation effects; recrystallisation; relaxation; atomic-scale processes; damage clusters; density functional theory; empirical potentials; heated crystal; initial defect profile; isolated defects; low-energy displacement damage events; molecular dynamics calculations; parameter-free quantum mechanical calculations; radiation damage; recrystallization; relaxation; secondary knock-on atoms; thermal annealing; threshold displacement energy; Annealing; Astronomy; Atomic layer deposition; Atomic measurements; Degradation; Physics; Probes; Quantum mechanics; Semiconductor devices; Volume relaxation; Density functional theory; displacement damage; local melting;
Journal_Title :
Nuclear Science, IEEE Transactions on
DOI :
10.1109/TNS.2007.910231