The study of preferred orientation growth of aluminum nitride thin films on ceramic and glass substrates

The preferred oriented aluminum nitride (AlN) films with the c-axis parallel to the surface have been grown and demonstrated on alumina and SiO2 substrates using off-axis rf sputtering. The film orientation as well as the crystallinity was found to be strongly dependent on the total sputtering pressure. Highly oriented films with c-axis parallel to the substrates can be obtained under a total pressure of 80 mTorr containing 75% nitrogen and 25% argon and a substrate temperature of 350 degrees C. The film orientation is beneficial for the thin film surface acoustic wave (SAW) device application. The deposition process on ceramic substrates as well as the model of growth mechanism shows the possibility of incorporating the thin film SAW devices with microwave integrated circuits.