Investigation of layered structure SAW devices fabricated using low temperature grown AlN thin film on GaN/sapphire

Epitaxial AlN films have been grown on GaN/sapphire using helicon sputtering at 300/spl deg/C. The surface acoustic wave (SAW) filters fabricated on AlN/GaN/sapphire exhibit more superior characteristics than those made on GaN/sapphire. This composite structure of AlN on GaN may bring about the development of high-frequency components, which integrate and use their semiconducting, optoelectronic, and piezoelectric properties.