Defects in epitaxial ScGaN: Dislocations, stacking faults, and cubic inclusions

The characteristic defect microstructure of epitaxial wurtzite ScxGa1−xN films on GaN was investigated. Threading dislocations in ScxGa1−xN are inclined with respect to [0001] to relieve in-plane compressive strains. However, increased densities of I1-type basal plane stacking faults and nanoscale lamellar zinc-blende inclusions in the (0001) plane occur with increasing x, in contrast to ScxAl1−xN. This behaviour occurs because the formation energy of the zinc-blende phase is close to that of the wurtzite phase for low Sc-content ScxGa1−xN but not for ScxAl1−xN.