X-ray diffraction from laterally structured surfaces: Crystal truncation rods

X-ray-diffraction measurements from single-crystalline GaAs(001) surface gratings are presented. The experiments were performed using a three-crystal diffractometer. The vicinity of the (004) Bragg reflection for five samples was investigated in detail. Model calculations based on the kinematical crystal truncation rod theory are able to explain all measurements quantitatively. Mesoscopic grating parameters as well as microscopic surface roughnesses of the samples were obtained from fits of the data. For three samples scanning electron microscope pictures were taken. The analysis of these pictures leads to the same mesoscopic parameters as obtained from x-ray Bragg diffraction.