X-ray diffraction study of AlN∕AlGaN short period superlattices

Short period superlattices of AlN∕Al0.08Ga0.92N with the average AlN content over 60% have been investigated by high resolution x-ray diffraction. The a and c lattice constants verify these structures to be strain relaxed. Monolayer-level interface roughness, caused by the presence of threading dislocations and step-flow growth mode, is simulated and directly compared with the zeroth and ±1 satellite peak positions of the rocking curves. It was found that the observed x-ray diffraction data can be adequately described by considering primarily the presence of screw dislocations and step-flow growth mode.