Numerical Study of S0 Lamb Mode Resonator based on c-BN/AlN for 5G Operating Acoustic Devices

The present work aims the numerical study of acoustic Lamb wave resonator LWR based on Aluminium Nitride (AlN) deposited on cubic Boron Nitride (c-BN). Finite element analysis is adopted to study the propagation of the fundamental symmetric Lamb mode S0 in AlN/BN. The propagation characteristics, such as phase velocity V-p, temperature coefficient of the frequency, reflectivity and electromechanical coupling factor K (2) are studied for different AlN and BN thicknesses. High velocity and K-2 > 6% are shown. The data used for temperature coefficient of the frequency are extracted from Density Functional Theory calculations from which a positive temperature coefficient of the frequency is obtained. The electrical admittance and the propagation losses are numerically investigated where a large band and a quality factor Q as high as 14 000 for S0 Lamb wave resonator with Copper Cu fingers are obtained. The obtained results show the novel properties of c-BN that contributes in enhancing the performances of Lamb wave resonators and the possibility to use c-BN as potential material in the development of large band and low loss S0 Lamb wave resonator operating in the 3.5 GHz band for 5G telecommunications.