Two methods to improve the performance of Monte Carlo simulations of ion implantation in amorphous targets

Two methods are described for improving the results of a Monte Carlo technique used to simulate the transport of energetic ions in amorphous targets in two dimensions. The target considered is a homogeneous monolayer. The Monte Carlo technique used is based on the TRIM program. The first method relies on the fact that some calculated data can be used more than once. The second method relies on the fact that a point source results in a rotation-symmetric ion distribution. To study the behaviour of the two methods a smoothness indicator was defined. It is a measure of the distance of a simulation result from the ideal result, i.e., the result based on an infinite number of ion trajectories. This indicator showed that a CPU time reduction of a factor of 80 was achieve