  CMOS-MEMS resonators seamlessly integrated in advanced integrated circuit
(IC) technology have the unique capability to enable unprecedented integration
of stable frequency references, acoustic spectral processors, and physical
sensors. Demonstrations of transducers leveraging piezoelectric properties of
emerging ferroelectric materials such as Hafnium Zirconium Oxide (HZO) and
Aluminum Scandium Nitride (AlScN) enable high figure of merit (FOM=k2Q)
resonators over a wide range of frequencies. CMOS-integrated ferroelectric
transducers using a thickness-scaled variant of these films for low voltage
operation are feasible by leveraging advancements in ferroelectric random
access memory (FRAM) and ferroelectric field effect transistors (FeFETs).
However, until now, there has not been a full treatment of the effects of
nonlinear large-signal behaviour on the performance of electromechanical
systems built using ferroelectric transducers in the low coercive voltage
regime. In this work, CMOS-MEMS resonators in a 130 nm process operating at
~700 MHz have been used as a vehicle for understanding the performance impact
of nonlinear piezoelectric transduction on frequency references and acoustic
filters. The first nonlinear large signal model for such resonators has been
developed and employed to extract the nonlinear characteristics over different
biasing and applied power. Operating conditions and design guidelines have also
been developed for these applications, which can be extended to all resonators
of this class. The crystallized understanding of large-signal operation of
ferroelectric transducers presented in this work provides opportunities to
design and demonstrate new capabilities of electromechanical devices in
monolithic CMOS-MEMS platforms.
