Ion-Sputter-Induced Nanodots on Si（110）： Ion Energy Dependence

Nanodot arrays were formed on Si(110) surface under normal-incident Ar ion sputtering at substrate temperature of 800℃ The ion flux was 20μA/cm^2, and the ion energies were 1-5keV. The surface was imaged by an atomic force microscope (AFM). It was found that with the increasing ion energy, the average e11ipticity of the dots changes in an oscillating manner; meanwhile the average dot size increases monotonously. Based on a dynamic continuum model, and taking into consideration the asymmetry of the Ehrlich-Schwoebel diffusions along the(100) and (110) crystallographic directions, we carry out the simulations, which reproduce the experimental results qualitatively.