Monte-Carlo program MODEX: Simulation of point defect clustering during irradiation and subsequent annealing

Abstract

A Monte Carlo program MODEX is presented, capable of simulating the defect clustering process during ion implantation and subsequent annealing. The program considers four different types of point defects, e.g. implanted ions, vacancies, self-interstitials and impurities, as mobile. Depending on the mobility of the point defect the diffusion equations are solved in the stationary or non-stationary form. The clustering process of point defects is described by a set of rate equations and is simulated through a number of elementary trapping and dissociation events. The use of the program is demonstrated in examples of helium implantation in molybdenum, vanadium and silicon and the simulation results are discussed in relation to the results of helium desorption experiments.