A parallel-plate actuated test structure for fatigue analysis of MEMS

Silicon, heavily used as a structural material in MEMS, is subject to several reliability concerns most importantly fatigue that can limit the utility of MEMS devices in commercial and defense applications. A novel parallel-plate actuated test structure for fatigue analysis of MEMS is designed in this paper, and the structure is fabricated by bulk micromachining. Firstly, according to the predefined dimensions, we gain the natural frequencies of the structure by modal analysis. Secondly, the pull-in voltages of bend mode and torsional mode are obtained respectively by the theoretical analysis and the electromechanical coupling finite element analysis, and the results substantiate that the two methods are approximate. Finally, a brief design of the structure´s micromachining is offered, and the structure has been fabricated, waiting for tests. All of the analysises indicate that the structure can meet the requirements of fatigue test.