| Abstract: |
Reaction of Mg with GaAs (001) surface occurs at substrate temperatures above 250 K and leads to 3D growth of an epitaxial, cubic reaction phase with a lattice constant of 0.62 + 0.02nm, 9% larger than GaAs. The resulting anistotropic, 3-demiensional (3D) heteroepitaxial microstructure was studied using in situ electron diffraction and Auger spectroscopy and ex situ atomic force microscopy (AFM). 3D structures develop that are elongated alone the GaAs [110] direction with aspect ratios (length-to-width) up to 20. These structures appear to be composed of isotropic islands from which elongated, tapered ridges extend in on direction along [110]. Analysis of AFM images and size distributions suggest a critical size for the initiation of ridge formation and a discontinuous, stepwise ridge development. Potential origins of this interesting microstructure are discussed. |
