Performance Enhancement of Integrated Micromechanical Resonators Using Generalized CMOS-MEMS Platforms

• Main Authors: Chen, Wen-Chien, 陳文健
• Other Authors: Weileun Fang
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/47063715191943538163

博士 === 國立清華大學 === 動力機械工程學系 === 101 === The CMOS-MEMS technology with many advantages, including smaller footprints size, without noise from bond pad, and standard foundry process, is utilized in this dissertation to develop various capacitively-transduced HF/VHF micromechanical resonators with several unique performances targeted for sensor, timing reference, and RF applications. To attain this goal, two generalized releasing post-process, such as oxide wet etching and metal wet etching techniques, compatible with 0.35 m 2P4M and 0.18 m 1P6M CMOS processes, were successfully developed to fabricated metal-type and oxide-type integrated resonators, respectively, with diverse structural designs as well as different material configurations. In addition to post-process development, this dissertation attend to improve main consideration of MEMS resonator design issues, such as motional impedance (Rm), quality factor (Q), thermal stability, frequency tuning, power handling capability, and feedthrough cancellation, through (1)gap reduction mechanism, (2)high-Q material and tiny-support, (3)oxide-metal composite, (4)elegant structural design, (5)resonator-array and bulk mode vibration, and (6)fully-differential electric setup, respectively, successfully demonstrating CMOS-MEMS resonators with better characteristics of relative low-Rm, high-Q, temperature compensated capability, quasi-linear frequency tuning ability, high power handling, large signal to noise ratio, than previous CMOS-MEM works. In addition, this dissertation also derive a generalized theoretical model of passive temperature compensation for composite bulk mode resonators, capable of further controlling its temperature coefficient of frequency (TCf) Such performance improved results might benefit the future integrated micromechanical oscillator design for timing or frequency reference in consumer electronics.