The role of antiphase domain boundary density on the surface roughness of GaSb epilayers grown on Si (001) substrates

GaSb epilayers were grown on nominal Si (001) substrates by molecular beam epitaxy, using AlSb nucleation layer (NL) as an interfacial misfit array. The effects of AlSb NL thickness, growth temperature and post annealing on the GaSb epilayers in terms of formation of antiphase boundaries (APBs) were monitored by scanning electron microscopy (SEM). APBs were identified via SEM following a defect sensitive etch solution treatment. SEM images of etched samples were used to calculate the APB densities and the results were correlated with the surface roughness of the samples. We found that the density of APBs together with the area peak-to-valley height has a role on the surface roughness of the GaSb epilayers grown on nominal Si (001) substrates.