Theoretical and experimental study of capacitance considering fabrication process and edge effect for MEMS comb actuator

Abstract

This paper introduces a new theoretical model of plate capacitor for MEMS comb actuator. In this model, bulk fabrication process and edge effect are both considered using integration method and conformal transformation theory. In order to verify the correctness of the model, FEM software is used to calculate the value of the capacitance of the MEMS comb actuator. The simulated result is 1.441 pF. Relative errors to the model calculated result 1.401 pF and ideal model calculated result 1.267 pF are 2.78 and 12.07% respectively. Then, high precision capacitance measuring device is used to measure the micro-fabricated comb actuator. The tested result is 1.517 pF. Its relative error to the rectified value is 7.65%, much less than the relative error to ideal result 16.48%. This further indicates the correctness of the rectified model.

Design and fabrication of the trapezoidal electrostatic comb-drive actuator

“…This phenomenon changes its capacitance, therefore, it varies forces applying on two plates. According to Guo Zhanshe et al [11], the capacitance C can be expressed as:…”

A passive mechanism for thermal stress regulation in micro-machined beam-type structures

“…The fringes effect for two parallel micro-beams has been studied (Osterberg and Senturia 1997). For three parallel beams, there are different numerical techniques for quantitatively determining effects of electric field fringes, including regular finite element analysis (Andreykiv and Rixen 2009;Boeloeni et al 2010;Zhanshe et al 2011) as well as extended finite element methods (FEMs) (Fries and Belytschko 2010).…”