Precision MEMS Timing: Microheater and Machine Learning Compensation for 21 PPT Stability at 7.5 Hours

This paper presents a dual-mode ovenized MEMS resonator clock that achieves a fractional frequency stability of 21 parts per trillion at 7.5 hours of averaging time. The device incorporates a micro-oven in-chip heater that thermally isolates and maintains the suspended MEMS resonator at its turnover temperature. The ultra-stable performance is enabled by leveraging a machine-learning algorithm to dynamically compensate for residual environmental perturbations within the frequency tracking electronics.