Columnar microstructure in step-graded Si1–xGex/Si(001) structures with low threading dislocation densities was determined using high angular resolution (about 0.005°) X-ray microdiffraction. X-ray rocking curves of a 3-µm-thick strain-relaxed Si0.83Ge0.17 film showed many sharp peaks and could be simulated with a model having a set of Gaussians having narrow angular widths (0.013°–0.02°) and local ranges of tilt angles varying from 0.05 to 0.2°. These peaks correspond to individual tilted rectangular columnar micro-grains having similar (001) lattice spacings and average areas of 0.8 to 2.0µm2.Observation of Columnar Microstructure in Step-Graded Si1–xGex/Si Films Using High-Resolution X-Ray Microdiffraction. D.E.Eastman, C.B.Stagarescu, G.Xu, P.M.Mooney, J.L.Jordan-Sweet, B.Lai, Z.Cai: Physical Review Letters, 2002, 88[15], 156101 (4pp)