Ion channeling analysis and x-ray diffraction reciprocal space maps have been performed onInxGa1−xAsbuffer layers grown with different composition profiles on well-cut (001) GaAs substrates. On all of the samples analyzed we detect acurvatureof the layer lattice, i.e., a tilt of the lattice with respect to the substrate which varies coherently along the sample surface. The layer tilt is directed inward defining a curvature that is concave, large (up to2.5° cm−1) and that decreases when approaching the substrate. We describe this new phenomenon in terms of a coherent lateral distribution of the orientations of the misfit dislocation Burgers’ vectors.