Influence of the side etching effect in DRIE on performance of electrostatic linear comb-drive actuators

Abstract

Side etching and scalloping are unwanted but unavoidable phenomenon occurring during fabrication process of micro electro-mechanical system devices with the deep reactive ion etching technology. This paper reports the influence of deep reactive ion etching fabrication errors on the geometrical dimension (as a comb finger shape, width of the suspension beam), electrostatic force and displacement of electrostatic linear comb-drive actuators. A number of deep reactive ion etching experiments were carried out in order to find out the optimal etching and passivation time, which allows to achieve vertical and smooth sidewall, as well as acceptable side etching value. Discussion and evaluation of deviation between the theoretically calculated and measured displacements of the electrostatic linear comb-drive actuator were also reported.