Effects of substrate miscut on dislocation glide in metamorphic (Al)GaInP buffers

The effects of miscut toward (111)A of (001) GaAs substrates on α dislocation glide in compositionally step-graded (Al)GaInP buffers grown by metal-organic chemical vapor deposition have been investigated. The full width at half maximum of X-ray rocking curves and the tilt obtained from symmetric (004) reciprocal space mappings suggest that the average misfit glide length of α dislocations is longer in samples on 15° off substrates than that on 7° off substrates. Compared to the 7° sample, the larger miscut 15° more significantly weakens the blocking effect of the β dislocations on the motion of α dislocations, and it also provides a much stronger driving force on α dislocations in (111) slip planes, which greatly enhances the misfit dislocation glide. Eventually, the two effects collectively lead to a longer average misfit glide length of α dislocations and a lower threading dislocation density in the active layer on the 15° off substrates, which is critical for improving the performances of devices based on lattice mismatched materials. •Metamorphic (Al)GaInP buffers were grown by MOCVD.•The threading dislocation density is much lower in the 15° sample compared to the 7° sample.•The average misfit glide length of 15° sample is longer than that of 7° sample.•Large driving force acting on α dislocations in the (111) plane promotes dislocation glide.