Differential piezoresistive sensing in a bulk‐mode micromechanical resonator. (1st February 2013)

• Record Type: Journal Article
• Authors: Wei, Xueyong; Seshia, Ashwin A.
• Is Part Of: Micro & nano letters. Volume 8:Number 2(2013)
• Page Start: 107
• Page End: 110
• Publication Date: 2013-02-01
• Subjects: 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; Nanotechnology -- Periodicals; Nanostructures -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1049/mnl.2012.0789
• Languages: English
• ISSNs: 1750-0443

Abstract

Abstract : 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.