ATOMIC-SCALE ROUGHNESS OF GAAS(001)2X4 SURFACES

The atomic structure and atomic scale roughness of GaAs(001)2x4 surfac es fabricated by molecular beam epitaxy was examined by scanning tunne ling and atomic force microscopy. In particular, the size and spatial distribution of atomic steps at the surface was quantitatively determi ned as a function of annealing time and annealing temperature. Two dif ferent, parameters are required to fully describe the surface roughnes s. In general, we found that prolonged annealing under vacuum of surfa ces produced by thermal desorption of As cap layers is sufficient to r educe the surface roughness to that typical of as-grown surfaces. (C) 1996 American Vacuum Society.