Cascade Annealing of Tungsten Implanted with 5 keV Noble Gas Atoms: A Computer Simulation

摘要

The trapping of vacancies by implanted atoms is calculated. After low energy implantation (5 keV) of tungsten with heavy noble gas atoms most of the implanted atoms are in substitutional position with one or two vacancies closer than two lattice units. Under the influence of the lattice distortion around the implanted atoms the vacancies follow a preferential migration path towards the implant during annealing. With lattice relaxation simulations migration energies close to the implanted atom are calculated. Monte Carlo theory is applied to obtain trapping probabilities as a function of implant-vacancy separation and temperature. An estimate of the initial implant-vacancy separation follows from collision cascade calculations. The results show that nearby vacancies are trapped by the implanted atoms.