Reducing Pull-In Voltage by Adjusting Gap Shape in Electrostatically Actuated Cantilever and Fixed-Fixed Beams

Micromachines

Darcy T. Haluzan¹  David M. Klymyshyn¹  Sven Achenbach¹ 

[1] Department of Electrical and Computer Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, Saskatchewan, S7N 5A9, Canada; E-Mails:

关键词: electrostatic;    actuator;    gap shape;    finite element;    MEMS;    pull-in voltage;    high aspect ratio;    LIGA;   

DOI  :  10.3390/mi1020068

来源: mdpi

【 摘 要 】

A gap with variable geometry is presented for both cantilever beam and fixed-fixed beam actuators as a method to reduce the pull-in voltage while maintaining a required displacement. The method is applicable to beams oriented either in a plane parallel to or perpendicular to a substrate, but is most suitable for vertically oriented (lateral) beams fabricated with a high aspect ratio process where variable gap geometry can be implemented directly in the layout. Finite element simulations are used to determine the pull-in voltages of these modified structures. The simulator is verified against theoretical pull-in voltage equations as well as previously published finite element simulations. By simply varying the gap in a linear fashion the pull-in voltage can be reduced by 37.2% in the cantilever beam case and 29.6% in the fixed-fixed beam case over a structure with a constant gap. This can be reduced a further 4.8% by using a polynomial gap shape (n = 4/3) for the cantilever beam and 1.2% for the fixed-fixed beam by flattening the bottom of the linearly varying gap.

【 授权许可】

CC BY   
© 2010 by the authors; licensee MDPI, Basel, Switzerland.