Electrostatic spring effect on the dynamic performance of microresonators

This paper reports on the significant discrepancy between the analytical and experimental resonant frequencies of folded beam micro resonators. Experimental results for the resonant frequency showed a consistent 20% discrepancy over theoretical and finite element results. Possible causes of the discrepancy from tapered cross section of the flexure beams, dimensional variations and electrostatic spring effects are discussed and shown to contribute to the significant difference between analytical and experimental values. IntelliCAD electrostatic simulation was done to isolate the electrostatic spring effect and compared with the experimental observations. The compliance due to AC voltage has also been observed in DRIE resonators.

[1]  T. Hirano,et al.  Operation of sub-micron gap electrostatic comb-drive actuators , 1991, TRANSDUCERS '91: 1991 International Conference on Solid-State Sensors and Actuators. Digest of Technical Papers.

[2]  F. Maseeh,et al.  Accurate fully-coupled natural frequency shift of MEMS actuators due to voltage bias and other external forces , 1999, Technical Digest. IEEE International MEMS 99 Conference. Twelfth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.99CH36291).

[3]  William C. Tang,et al.  Laterally driven polysilicon resonant microstructures , 1989, IEEE Micro Electro Mechanical Systems, , Proceedings, 'An Investigation of Micro Structures, Sensors, Actuators, Machines and Robots'.

[4]  L. Warne,et al.  Electrophysics of micromechanical comb actuators , 1995 .