A Temperature-Insensitive CMOS-MEMS Resonator Utilizing Electrical Stiffness Compensation
Journal
Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)
Journal Volume
2019-January
Pages
161-164
Date Issued
2019
Author(s)
Abstract
A temperature-insensitive micromechanical resonator that utilizes an electrical stiffness compensation technique was demonstrated. In particular, a 2.92-MHz free-free beam (FF-beam) resonator based on a 0.35-μm 2-poly-4-metal CMOS-MEMS process platform cancels the first-order temperature coefficient of frequency (TCF1), from - 70.03 ppm of an uncompensated version to +0.44 ppm, and a 22× lower overall frequency drift from the uncompensated 2120 ppm to 95 ppm from 25°C to 55°C. In contrast to the previously demonstrated electrical stiffness compensated resonator, for which the resonator consists of an out-of-plane overhanging temperature-compensating electrode realized by a CMOS-incompatible poly-Si surface micromachining process, this work employs an in-plane U-shaped compensating electrode design that allows the use of a standard CMOS-MEMS process platform for achieving the device. The FEA-derived thermal expansion of the compensating electrode is used to predict the temperature coefficient of frequency. The measured results is compared with a finite element analysis.
Type
conference paper