A method for analysis includes directing a converging beam of X-rays toward a surface of a sample having multiple single-crystal layers, including at least a first layer and a second layer that is formed over and tilted relative to the first layer. The X-rays that are diffracted from each of the first and second layers are sensed simultaneously while resolving the sensed X-rays as a function of angle so as to generate a diffraction spectrum including at least a first diffraction peak due to the first layer and a second diffraction peak due to the second layer. The diffraction spectrum is analyzed so as to identify a characteristic of at least the second layer.