Microstructures and electrical properties of nanostructured Cr2O3 thin films deposited by dual-target reactive high-power impulse magnetron sputtering

Abstract Nanostructured Cr 2 O 3 thin films were deposited on silicon (100) and 95% alumina substrates at various substrate temperatures and oxygen flow rates using dual-target reactive high-power impulse magnetron sputtering. Grazing incidence X-ray diffraction analysis revealed that the phase structure of the Cr 2 O 3 films varied with the substrate temperature and oxygen flow rate and that a Cr 2 O 3 film with good crystallinity was produced at 300 °C. X-ray photoelectron spectroscopy analysis indicated that an oxygen flow rate of 5 sccm was suitable for depositing a stoichiometric Cr 2 O 3 film. Scanning electron microscopy analysis revealed that the films prepared at oxygen flow rates of 3–15 sccm exhibited a homogenous and uniform nanocrystalline structure. In addition, all the Cr 2 O 3 -modified alumina samples exhibited a secondary electron emission (SEE) yield of 2.3, which was much lower than that of the bare alumina (6.82). The sheet resistivity of the Cr 2 O 3 -modified alumina samples increased from 8.6 × 10 10 to 6.2 × 10 11  Ω/□ upon increasing the oxygen flow rate from 3 to 15 sccm. Thus, the deposition of the Cr 2 O 3 film significantly reduced the SEE yield and sheet resistivity of the alumina substrate. In addition, the surface hold-off voltage of alumina was enhanced by up to 23.7%.