Published online by Cambridge University Press: 26 February 2011
We present in this paper the effect of heat treatments applied to a 400 nm GaAs layer grown by MBE on a (001) Silicon substrate. These heat treatments have been applied during or after the growth of the GaAs, in order to improve the crystalline quality of the layer. RBS and TEM observations have been performed to study the improvement of the crystalline quality of the GaAs layer. Specimens, prepared by cross-section technique along both (110) and (170) planes and plane view, have been studied by TEM. Observations of cross-section by HREM show an interface roughness of about 1.5 nm before and after heat treatments. A roughness, observed also by RHEED, appears in the first stage of growth. Although the density of threading dislocations decreases after heat treatments.