GHZ-BAND SURFACE-ACOUSTIC-WAVE DEVICES USING ALUMINUM NITRIDE THIN-FILMS DEPOSITED BY ELECTRON-CYCLOTRON-RESONANCE DUAL ION-BEAM SPUTTERING

AlN thin films have been deposited on basal plane ((001)Al2O3) and R-plane ((112BAR)Al2O3) sapphire by an ECR dual ion-beam sputtering method. The (001) plane of AlN was epitaxially grown on (001)Al2O3. On the other hand, it was found that the (001) plane of AlN was deposited on (112BAR)Al2O3 With an inclination of about 26 degrees against the substrate, and a surface wave having high coupling and high velocity (6684 m/s) was excited on this substrate. Resonator-type 1.67 GHz band SAW filters have been fabricated using AlN thin film deposited on (112BAR) Al2O3. The insertion loss, suppression and TCD were 7.9 dB, more than 20 dB and 35 ppm/degrees-C, respectively. These are the best values yet in a GHz band SAW filter based on AlN thin film, and are good enough to allow practical use.