Effects of shadowing and steering in oblique-incidence metal (100) epitaxial growth

Abstract

The effects of attraction in oblique-incidence metal (100) epitaxial growth are studied by comparing the results of simulations which include the effects of short-range (SR) and long-range (LR) attraction with results obtained in the absence of attraction. In general, we find that the qualitative dependence of the surface morphology on deposition angle and film thickness, including the existence of a transition from mounds to asymmetric ripples oriented perpendicular to the beam at large deposition angles, as well as a second transition from ripples to rods with (111) facets oriented parallel to the beam at larger deposition angles and film thicknesses, is not altered by the presence of attraction. However, we find that attraction can have two important effects. The first effect, which is a result of steering due to LR attraction and leads to decreased shadowing, leads to decreased anisotropy in the submonolayer regime and can also lead to decreased surface roughness for high-deposition angles and intermediate film thicknesses. The second effect, due to flux focusing, leads to an increase in the surface roughness and feature size and also reduces the critical thickness for ripple and rod formations. This effect also tends to limit the anisotropy in the rod phase for high-deposition angles and film thicknesses. Surprisingly, we also find excellent scaling for the surface roughness as a function of deposition angle and film thickness in the presence of attraction. We also present extensive results for the dependence of the surface morphology on a variety of other parameters including azimuthal angle, growth temperature, deposition flux, and crystal geometry. A comparison between our simulation results and recent experimental results for grazing incidence Cu/Cu(100) growth is also presented.