Strain relaxation mechanisms in step-graded SiGe/Si(1 1 0) heterostructures grown by gas-source MBE at high temperatures

We investigated the growth temperature dependence of the defect morphologies in the SiGe films grown on Si(1 1 0) substrates. The substrate temperature range in this investigation was 700–800 °C. The samples were comprised of compositionally graded and uniform layers. A transition in the strain relaxation mechanism from microtwin formation to dislocation generation was newly found, which occurred at 800 °C.