Title:  Advanced Single-chip Temperature Stabilization System for MEMS Resonators and Gyroscopes

Committee:

Dr. Farrokh Ayazi, ECE, Chair , Advisor

Dr. Arijit Raychowdhury, ECE

Dr. Hua Wang, ECE

Dr. John Cressler, ECE

Dr. Peter Hesketh, ME

Abstract:

The main objective of this research is to develop temperature and frequency stabilization techniques for silicon MEMS oven-controlled crystal oscillators (MEMS OCXO) with high-frequency stability. The device is built upon an ovenized platform that uses a micro-heater to adjust the temperature of the resonator. Structural resistance-based temperature sensing is used to improve the self-temperature monitoring accuracy of the silicon MEMS resonator. An analog feedback micro-oven control loop and a feedforward digital calibration scheme are developed for a 77MHz MEMS oscillator, which achieves a ±0.3ppm frequency stability from -25°C to 85°C. This temperature stabilization technique is also applied to silicon MEMS mode-matched vibratory x/y-axis and z-axis gyroscopes on a single chip. The temperature-induced frequency change, scale factor and output bias variations are all reduced significantly. The complete interface circuit for the single-chip three axes gyroscopes were also developed with an innovative trans-impedance amplifier to reduce the input-referred noise. For the first time, the simultaneous operation of mode-matched vibratory 3-axis MEMS gyroscopes on a single chip is demonstrated.