A series of InxGa1-x As films with different compositions around x=0.53 were grown on InP(001) substrates by molecular beam epitaxy. These layers were studied by double crystal x‐ray diffraction and secondary electron microscopy. It was found that the broadening of a layer Bragg peak is an indication of a large scale lattice relaxation in the highly strained heterolayer. In the less strained layers the peak widths are due to sample curvature and compositional grading. The morphologies of the strained layers suggested that the sign of strain is an important factor affecting the growth kinetics on the surface. In particular, an increasing tensile strain in the epitaxial layer tends to decrease the migration rate of the species on the growing surface.