Modeling and Design of AlN Based SAW Device and Effect of Reflected Bulk Acoustic Wave Generated in the Device

Investigations of the effect of generation and reflection of bulk acoustic waves (BAWs) on the performance surface acoustic wave (SAW) device using finite element method (FEM) simulation is carried out. A SAW delay line structure using Aluminum Nitride (AlN) substrate is simulated. The dimension of the device is kept in the range of the 42 22.5 m in order to analyze the effect in MEMS devices. The propagation of the bulk wave in all the direction of the substrate is studied and analyzed. Since BAW reflect from the bottom of the SAW device and interfere with the receiving IDTs. The output of the SAW device is greatly affected by the interference of the BAW with SAWs in the device. Thus in SAW devices, BAW needed to be considered before designing the device.