Step structure and interface morphology: Arsenic on vicinal silicon surfaces

Abstract

Changes in the structure of the steps on vicinal Si(100) and Si(111) due to arsenic adsorption have been characterized using low-energy electron diffraction. Under equilibrium conditions all the surfaces studies show reversible step rearrangements as a function of arsenic coverage. On vicinal Si(111) double layer steps form at approximately 0.2 ML of As. On vicinal Si(100) arsenic adsorption causes the steps to group to form facets. If the surfaces are not equilibrated, the step structures formed depend sensitively on preparation procedure. Prior observations on the growth of GaAs on stepped Si(100) are discussed in terms of our observations of step rearrangements.