Intensity oscillations for electron beams reflected during epitaxial growth of metals

Abstract

Beam intensities in reflection high-energy electron diffraction (RHEED) are observed to oscillate during the epitaxial growth at 300 K of body-centered-cubic nickel on the (100) surface of iron and of face-centered-cubic Ni on the (100) surface of Ni. Such oscillations have been studied thoroughly by others for the growth of GaAs by molecular-beam epitaxy, where there is little doubt about the mechanisms of layer-by-layer growth. Because the RHEED oscillations are observed on vicinal surfaces [e.g., the (100) planes of the iron substrate are misoriented with respect to the surface by \ensuremath{\sim}30 mrad], the implication is that diffusion of Ni is sufficiently slow that growth does not take place by growing from the step edges, yet fast enough for completion of one monolayer before substantial development of the next. The demonstrated utility of RHEED oscillations for monitoring controlling growth in GaAs is now applicable to metal growth.