Shear mode coupling and properties dispersion in 8 GHz range AlN thin film bulk acoustic wave (BAW) resonator

8GHz range solidly mounted resonator (SMR) based on high quality direct current pulsed sputtered aluminum nitride (AlN) thin films have been fabricated on 100 mm diameter silicon wafer. Dispersion in AlN film thickness has been measured and on-wafer distribution of operating frequency, mechanical coupling and quality factor of the SMR has been investigated. Data is presented showing efficient coupling of a shear mode resonating in the 4GHz range. This coupling was found to increase with wafer radius and related to the increasing tilt of crystalline c-planes of AlN thin film. (c) 2006 Elsevier B.V. All rights reserved.