A comprehensive study of material and structural designs of bulk acoustic resonator (BAR) filters for wireless applications

A study of a solidly mounted bulk acoustic wave resonator (SMR) filter is presented. An overall design and fabrication summary is described, with both materials and structures of the resonator devices considered. Aluminum Nitride (AlN) is utilized as the piezoelectric material to convert electromagnetic signals to acoustic waves. Molybdenum (Mo) is used as the electrode material. A distributed Bragg reflector (DBR) stack of alternating Tungsten (W) and Silicon Dioxide (SiO2) is embedded. Basic device fabrication process steps are presented, and measured filter responses are compared with simulated filter responses.