Nucleation of Ge nanoislands on Si by pulsed ion irradiation

The effect of ion beam irradiation on nucleation and growth of three-dimensional (3D) Ge islands on Si (100) substrate was investigated. It was found that pulsed ion-beam action during heteroepitaxy leads to the increase of 3D islands density, decrease of their size and improvement of the size uniformity. To reveal the mechanisms of observed effects Monte Carlo simulation was made. It was shown that the density of 3D islands and their size distribution depend on the ion penetration depth and moment of ion-beam action on the growing surface during Ge/Si heteroepitaxy.