Electrostatic model for an asymmetric combdrive

Author

Yeh, J. L Andrew ; Hui, Chung-Yuen ; Tien, Norman C.

Author_Institution

Sch. of Electr. Eng., Cornell Univ., Ithaca, NY, USA

Volume

9

Issue

1

fYear

2000

fDate

3/1/2000 12:00:00 AM

Firstpage

126

Lastpage

135

Abstract

This paper presents an analytical solution to the electrostatic actuation of an asymmetric combdrive in out-of-plane and torsional motions. The exact solutions to force in the out-of-plane motion and the integral for torque in the torsional motion are obtained. The dependence of the peak force on the thickness of the movable fingers and the amount of overlap of the combs is given in closed form. Using our model, the shift of the natural resonant frequency due to a dc bias is analyzed. Furthermore, our solution also applies to the in-plane motion of an in-plane interdigitated combdrive. We found that an in-plane interdigitated combdrive generates a constant force within 0.1% when the minimum initial engagement length of the combs is twice the separation gap.

Keywords

electrostatic actuators; semiconductor device models; torque; torsion; DC bias; MEMS; asymmetric comb drive; comb overlap amount; constant force; electrostatic actuation; electrostatic model; exact solutions; interdigitated comb drive; movable finger thickness; natural resonant frequency; out-of-plane motion; peak force; torque; torsional motion; Electrodes; Electrostatic actuators; Etching; Fingers; Mechanical sensors; Micromachining; Micromechanical devices; Resonant frequency; Silicon; Torque;

fLanguage

English

Journal_Title

Microelectromechanical Systems, Journal of

Publisher

ieee

ISSN

1057-7157

Type

jour

DOI

10.1109/84.825787

Filename

825787