Relaxation and rocking-curve broadening of strained (Ga,In)As single layers on (001) GaAs

We have measured the lattice relaxation of various strained Ga1−xInxAs layers which are thicker than the equilibrium critical thickness. Samples with a thickness near the energy balance model critical thickness exhibited a large relaxation. We have analyzed the strain relaxation data in a GaInAs/GaAs system using the Dodson–Tsao plastic flow model [Appl. Phys. Lett. 52, 852 (1988)]. It was found that the model provides a reasonably good fit to the data, however, the model parameters have widely different values for the GaInAs/GaAs samples with different mismatches. One parameter of the model shows an approximate inverse-square-law dependence on the misfit. The rocking-curve linewidths are presented for the GaInAs layers. The measured linewidths are discussed in terms of the theoretical linewidth, dynamical x-ray diffraction, and defect density depth distribution.