Parametric excitation in geometrically optimized AlN contour mode resonators

This work reports the first observation of parametric excitation in geometrically optimized Aluminum Nitride (AlN) contour mode resonators (CMRs). The concept of parametric excited AlN CMRs harnesses the fact that the resonant frequencies of extensional mode vibrations along transverse and longitudinal directions can both be determined by resonator dimensions. Therefore, by geometrically optimizing lateral dimensions, dual resonances can be engineered at f₀ and 2f₀ respectively for inputting parametric excitation and outputting fundamental oscillations. In operation, the parametric excitation amplifies an orthogonal oscillation at f₀ by periodically modulating the stiffness constants of AlN piezoelectric thin film via straining the structure. The experimental results have shown quality factor (Q) enhancement from 50 ot 2708 for a parametrically excited resonance. Upon further scaling and optimizations, it is anticipated that this type of devices will lead to the development of GHz low noise frequency sources and nano-electro-mechanical logic.