Monte Carlo simulation of charge exchange processes in the scattering of 4 keV He+ ions by an amorphous silicon surface

Charge exchange in the scattering of slow He+ ions off an amorphous silicon surface is studied. For this purpose, numerical simulation based on a Monte Carlo method is used to compute TOF spectra and positive charge fraction of the scattered particles. This simulation takes into account two charge exchange processes (Auger neutralization and charge exchange in close collisions). The image effect on ion trajectories in incoming and outgoing channels is equally considered. Comparison is done with experimental results about the scattering of 4 keV He+ ions from a silicon surface. This method allows the determination of different parameters governing the particle–matter interaction at low energy.