Growth process of crystalline GaAs on Si(110) surface kept at 773 K and the nanostructural analysis of the interface have been studied by a combination of reflection high-energy electron diffraction (RHEED) and cross-sectional transmission electron microscopy (TEM) observations. The Si(110) facetted surface along the < 001 > direction consists of vicinal surfaces inclined +/- 2 degrees from the < 110 > direction. In earlier stage of the growth up to the coverage of 12 ML, the vicinal facetted surface is filled from the bottom terraces by GaAs layers and consequently a flat surface is constructed. With increasing layer thickness of GaAs, stacking faults and the subsequent deformation twins are introduced to relax the lattice strain accumulated in the layer by themselves. (c) 2005 Elsevier B.V. All rights reserved.