Epitaxial growth of Sc2O3 films on GaN

Thin films of scandium oxide were epitaxially deposited on GaN via molecular beam epitaxy using elemental Sc and an oxygen plasma. After growth, the Sc2O3 films were annealed at a temperature of 800°C for 5min in the growth chamber. The structural quality of Sc2O3 films, before and after annealing, was characterized using high-resolution x-ray diffraction, atomic force microscopy (AFM), and high-resolution transmission electron microscopy (HRTEM). AFM of the films revealed smooth surfaces with 0.38nm root mean square roughness and show evidence of step-flow growth. The rocking curve and reflectivity scans of the films reveal that the Sc2O3∕GaN interface is abrupt and that it remains so after annealing. Pole figure and grazing incidence θ-2θ measurements show that the films are very textured along the c axis of the GaN substrate. HRTEM produced lattice images of the Sc2O3∕GaN interface illustrating the single crystal growth of the Sc2O3 films on the GaN.