Microelectromechanical (MEMs) resonators can provide small form factor, ease of integration with conventional semiconductor fabrication techniques and high f·Q products. High frequency and high-Q width-extensional mode silicon bulk acoustic resonators (SiBARs) and film bulk acoustic wave resonators (FBARs) have demonstrated atmospheric quality factors (Q) in excess of 10,000 at or above 100 MHz, with moderate motional resistances. Such resonators are disclosed in an article by S. Pourkamali et al., entitled “Low-Impedance VHF and UHF Capacitive Silicon Bulk Acoustic Wave Resonators—Part I: Concept and Fabrication,” IEEE Trans. On Electron Devices, Vol. 54, No. 8, pp. 2017-2023, August (2007), the disclosure of which is hereby incorporated herein by reference.
Unfortunately, such resonators may be characterized by relatively high temperature coefficient of frequency (TCF) values that require active compensation using temperature compensation circuits and/or relatively complex fabrication techniques to reduce TCF. Circuit-based compensation techniques typically increase the complexity of a resonator device and increase power consumption. Alternatively, fabrication-based compensation techniques that reduce TCF may cause a reduction in resonator quality factor (Q) and/or increase in resonator insertion loss.