Atomistic simulation of stress effects in a-Si due to low-energy Si impact

Using molecular-dynamics simulation, we study the response of an initially defect-free a-Si sample to Si atom bombardment with energies between 10 and 150 eV. In particular, we compare the results for a stress-free sample with those of a sample which has been initially subjected to compressive stress. For the compressed sample, we find a slightly decreased ion range and a considerably increased damage production. While in the stress-free sample, the stress is only little affected by the atom impact, the compressed sample shows distinct stress changes: for ion energies below 50 eV, it is further compressed, otherwise it is relaxed. We analyze this behavior by considering the recoil-implanted target atoms and the atoms energized in the collision cascade.