Differential piezoresistive sensing in a bulk-mode micromechanical resonator

Micro & nano letters

article

Xueyong Wei¹  Ashwin A. Seshia¹ 

[1] Department of Engineering, University of Cambridge, United Kingdom

关键词: capacitive sensors;    micromechanical resonators;    piezoresistive devices;    bulk-mode micromechanical resonator;    motional response;    stiffness;    motion range;    capacitive sensing method;    large parasitic feedthrough;    differential piezoresistive sensing approach;    parasitic capacitive feedthrough effects;    differential pick-up;    feedthrough drop;    resonant peak magnitude;    drain current;    piezoresistive sensing scheme;    gain 33 dB;    current 1 mA;    voltage 5 V;   

DOI  :  10.1049/mnl.2012.0789

学科分类：计算机科学（综合）

来源: Wiley

【 摘 要 】

A report is presented on a differential piezoresistive sensing approach for transducing the motional response of bulk-mode micromechanical resonators. High-frequency bulk-mode micoresonators have inherently high stiffness and demonstrate limited range of motion, which in turn presents challenges for the capacitive sensing method in the presence of large parasitic feedthrough. A differential piezoresistive sensing approach is implemented in this Letter to substantially reject the effects of parasitic capacitive feedthrough, leaving the response recovered directly from the measurement. With differential pick-up, a 33 dB drop of feedthrough has been achieved and a resonant peak magnitude of 14 dB is obtained for a drain current of 1 mA, which is shown to be approximately 20 times higher than that obtained for the conventional piezoresistive sensing scheme. This method also enables a low DC voltage for capacitively driving the bulk-mode resonator. As an example, a resonant peak magnitude of 5 dB is demonstrated using 3.55 mA drain current and 5 V DC driving voltage.

【 授权许可】

CC BY|CC BY-ND|CC BY-NC|CC BY-NC-ND