Response analysis of MEMS based high-g acceleration threshold switch under mechanical shock

Abstract

Failures of MEMS devices under shock are due to the overlap of the static and moving parts. The shock response of the microstructure under mechanical shock is investigated in this paper. This work presents modelling and simulation of the microstructures such as microcantilever, fixed–fixed flexure and serpentine structure and is further extended to optimize the response of high-g acceleration threshold switch under mechanical shock. The latching threshold for the high-g acceleration switch is estimated using the geometrical structure. The natural frequency of the serpentine spring-mass structure is selected to achieve the required displacement for latching. The dimensions of the switch are optimized in accordance with the natural frequency and to meet the requirement of latching for a given shock. The switch is fabricated on silicon on insulator wafer with a deep reactive ion etching process. The switch is tested on the static mechanical shock of 3500 g and shows a good agreement between analytical, numerical and experimental results.