Impacts of Heavy Particle Irradiation on Very High Frequency Microelectromechanical Resonators

This study explores the interrelationship between silicon ion irradiation and piezoelectrically-actuated microelectromechanical systems (MEMS) resonators. Specifically, it assesses the effect of incorporating a thin silicon oxide (SiO
2
) dielectric layer into the resonator structure. The MEMS resonators engineered for this investigation include Aluminum Nitride on Silicon (AlN-on-Si) and AlN-SiO
2
-Si width extensional mode (WEM) types. These devices underwent irradiation with 2 MeV Si
⁺
ions at a total fluence of 5 x 10
¹⁴
ions cm
^-2
. On-site S-parameter measurements were conducted. The research quantitatively outlines radiation-induced damage coefficients, elucidating their influence on key performance metrics such as resonant frequency (f
r
), quality factor (Q), motional resistance (R
m
), and electromechanical coupling factor ($\left({{k_{eff}}^2}\right)$.