Epitaxial growth of Sc_2O_3 films on GaN

摘要

Thin films of scandium oxide were epitaxially deposited on GaN via molecular beam epitaxy using elemental Sc and an oxygen plasma. After growth, the Sc_2O_3 films were annealed at a temperature of 800 ℃ for 5 min in the growth chamber. The structural quality of Sc_2O_3 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 0.38 nm root mean square roughness and show evidence of step-flow growth. The rocking curve and reflectivity scans of the films reveal that the Sc_2O_3/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 Sc_2O_3/GaN interface illustrating the single crystal growth of the Sc_2O_3 films on the GaN.