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Haoshen ZHU, PhD student , Department of Electronic Engineering, City University of Hong Kong

Theme: Power handling and Temperature Stability of Single-Crystal-Silicon Microresonators for High-performance MEMS Oscillators: Modeling and Experimental Verification
Date: July 16th, 2013 (Tuesday) - 10:00 , TIMA Laboratory - Room T312

Biography

Haoshen ZHU received the B.E. degree in Electrical Engineering from Wuhan University of Technology, in 2009. He is currently working toward the Ph.D. degree in the Department of Electronic Engineering, City University of Hong Kong. He is also currently affiliated with the State Key Laboratory of Millimeter Waves. His current research interests include design and modeling of micromechanical resonators, particularly for high performance MEMS oscillator applications. He is a student member of the IEEE.

Abstract

With the advantages of high quality factor, small size, and compatibility with modern IC fabrication process, the silicon micromechanical resonator (microresonator) has attracted much research interest recently and is regarded as a possible alternative to the quartz crystal resonator in the frequency control and timing market. Currently, the power handling capability and frequency stability over temperature still limit the performance of silicon MEMS oscillators and are pose major challenges for replacing quartz oscillator.
In this talk, the nonlinear behavior of the microresonator, which determines the power handling limit, is modeled and simulated in a system-level equivalent circuit model. Then, more specifically, the measured distinctive nonlinear behavior of the single-crystal-silicon (SCS) based Lamé-mode microresonator aligned with different crystal orientations are studied with the aid of atomistic-level simulation. For the temperature stability, a quantitative study based on free carrier contribution on elastic constants is performed to predict the temperature coefficient of frequency (TCf) of SCS microresonators in different contour modes and crystal orientations, which indicates the potential to engineer the temperature-stable MEMS oscillator via proper design. Finally, a prototype of a 17.6MHz Lamé-mode MEMS oscillator based on a wafer-level vacuum packaged silicon microresonator is demonstrated showing a phase noise performance of around -127dBc/Hz at 1kHz offset.