ANISOTROPIC STRAIN ESTIMATED FROM LATTICE-PARAMETERS MEASURED BY BONDMETHOD USING X-RAY-DIFFRACTION, IN MOLECULAR-BEAM EPITAXY-GROWN GAAS SI(001)/

x-, y- and z-components of lattice parameters on GaAs in GaAs films gr own on Si(001) substrates by molecular-beam epitaxy have been experime ntally measured from (004), (115) and (404) diffractions of GaAs by th e Bond method using X-ray diffraction (XRD). The anisotropic strain on GaAs is estimated from the difference in each component of lattice pa rameters between the film and the GaAs bulk crystal. In-plane componen ts of mechanical stress on GaAs are estimated from the measurement of substrate curvature using double-crystal XRD. The elastic strain is al so estimated from the stress, assuming an elastic distortion of the la ttice. However, it does not coincide with the strain derived from latt ice parameters. The difference in the strain estimated by the two meth ods is largely especially near the interface, indicating strong, aniso tropic and plastic deformation of the lattice, so that it can no longe r be regarded as an elastic body. It is probably caused by lattice and stress relaxation related to the anisotropy of dislocations in the fi lm.