An oven controlled piezoelectric MEMS dual-resonator platform with frequency stability of ±100 ppb over industrial temperature range

This work demonstrates a piezoelectric MEMS dual-resonator platform with an oven control. The platform includes a micro-oven in-chip, which integrates a frequency output resonator and a temperature sensing resonator. The two resonators operate using a phase-locked loop system, one in width-extensional (WE) mode and the other in width-shear (WS) mode. An equivalent thermal model of the dual-resonator platform is established and both resonators exhibit extremely uniform temperature distributions. The real-time temperature of the resonators is monitored by measuring the frequency difference between the two resonators and a closed-loop oven control is implemented to maintain the dual-resonator platform at an oven-set temperature. The reported oven controlled piezoelectric MEMS dual-resonator platform exhibits a measured frequency stability of $\pm$100 ppb across the industrial temperature range of $-$40 to 85 °C. This result signifies the promising potential of the device in high-end timing applications.