A Contour Mode AIN Piezoelectric Resonator based on SOI Substrate

Abstract

Aluminum nitride (AIN) piezoelectric MEMS resonators have been extensively developed in recent years due to their small size and CMOS compatibility. In this paper, a simple microfabrication process based on Silicon on Insulator (SOI) is presented to fabricate a contour mode resonator, and the piezoelectric material is aluminum nitride (AIN). SOI wafer is directly applied as the substrate and patterned as bottom electrode. Theoretical calculation and finite element method simulation is performed to estimate the resonant frequency. X-Ray Diffraction (XRD) is used to detect the full width at half maximum (FWHM) of AIN which is 0.164°. AFM is applied to measure the roughness of AIN film and the measured RMS roughness is 0.87 nm. Vector network analyzer and probe stations are applied to measure the one- port S parameter. It is founded that the result of resonant frequency is very close between the simulation and the actual measurement which is 146.9MHz and 144MHz. The resonator may find wide application in biosensing.