Abstract
We report on grazing scattering of 25 keV He+ ions during epitaxial growth of Cr on Fe(100). The angular distribution and intensity of the scattered particles depend on the coverage in an oscillatory way, which is due to the periodical change of the surface morphology in two-dimensional growth. At high growth temperatures (600 K), pronounced oscillations which persist with little decay in the amplitude indicate (almost) ideal layer-by-layer growth; at low temperatures (350 K), strongly damped oscillations and low intensities of scattered projectiles are due to transient layer-by-layer growth. The angular distributions are well described by Monte Carlo simulations using a classical description for the trajectories. This enables one to derive detailed information on the morphology of the growth front, like, e.g., the mean island distance.