Velocity reduction of incredible high-performance surface acoustic wave using heavy metal electrodes

Abstract

Abstract In this work, a technique to reduce the acoustic velocity of incredible high-performance surface acoustic wave (I.H.P. SAW) using Al/Pt electrodes keeping other important characteristics such as fractional bandwidth and quality factor is proposed. First, using a finite element method simulator, variations of the acoustic velocity and the fractional bandwidth of the I.H.P. SAW with the Pt electrode thickness, thicknesses of LiTaO 3 (LT) and SiO 2 layers in a substrate, and the cut angle of a LT layer are estimated. And then, to confirm the validity of the estimation results, several one-port SAW resonators with various thickness combinations of Al, Pt, LT, and SiO 2 layers are fabricated and their characteristics are evaluated. The evaluation results show that the acoustic velocity of the I.H.P. SAW is successfully reduced keeping the bandwidth, the quality factor, and the temperature characteristics.