Plasma enhanced chemical vapor deposition of Cr2O3 thin films using chromium hexacarbonyl (Cr(CO)6) precursor

Chromium oxide (Cr2O3) thin films have been deposited by plasma enhanced chemical vapor deposition on c-cut sapphire (Al2O3) and oxidized silicon substrates at temperatures between 250 and 400 °C using the precursor chromium hexacarbonyl (Cr(CO)6). The film growth rate ranges between 5 and 14 Å/min, with the growth rate going through a maximum at 300 °C before decreasing at higher temperature, suggesting the presence of competing deposition and desorption reaction channels. Scanning electron microscope images indicate that the density of grains and film crystallinity increases with increasing substrate temperatures, while atomic force microscopy shows an overall decrease in film roughness with increasing temperature. Normal θ – 2θ Bragg X-ray diffraction results show that films deposited on SiO2 are polycrystalline, while those on sapphire have a preferred (0 0 0 l) orientation. The epitaxial nature of the film growth on Al2O3 has been confirmed from the symmetry of off-axis X-ray scans.