Experimental and theoretical studies of the low-temperature growth of chromia and alumina

This paper describes the results of experimental and theoretical studies on the role of phase-stabilization and point defects in the growth of α-Al₂O₃ alumina and eskolaite Cr₂O₃ chromia. The experimental approach has been to utilize the similarity in the structure of α-Al₂O₃ and Cr₂O₃, so that the chromia acts as a 'template' to the growth of the α phase. The aluminium and chromium oxides (and their alloys) are grown in the temperature range of 300-500°C from elemental beams of chromium and/or aluminium and an oxygen plasma source. The theoretical studies have utilized Molecular Dynamic and Monte Carlo methods to investigate several important factors such as native defects (e.g. vacancies and interstitials), impurities (e.g. Fe) and diffusion barriers, which significantly affect the phase stability and the manner in which α-Al₂O₃ thin films form.