Localized epitaxial growth of α-Al2O3 thin films on Cr2O3 template by sputter deposition at low substrate temperature

Low-temperature growth of alpha-Al2O3 films by sputtering was studied with x-ray diffraction and high-resolution transmission electron microscopy (HRTEM). Pure alpha-Al2O3 film was formed at 400 degreesC using Cr2O3 as template, whereas amorphous or theta-Al2O3 was formed without Cr2O3. HRTEM revealed localized epitaxial growth of alpha-Al2O3 on Cr2O3 with the relationship [011](Al2)O-3/[011](Cr2)O-3, suggesting the importance of Cr2O3 as a structural template for the growth of alpha-Al2O3, in addition to other contributions such as good stoichiometry, low sputter pressure, and low deposition rate under optimized deposition conditions. Successful growth of alpha-Al2O3 by sputtering at 400 degreesC or below makes the film widely applicable to even glass substrates. (C) 2003 American Institute of Physics.