Methods and Techniques for MEMS Dynamic Characteristics Measurement under the Harsh Environment

Abstract

In order to study the dynamic characteristics of microstructures under high-g acceleration and harsh temperature environment, dynamic measurement techniques were presented and the corresponding testing systems were established. For testing in high-g acceleration environment, the acceleration was generated by high speed rotation plate, and over 10000 g acceleration environment was created. The base excitation device designed with piezoelectric ceramic (PZT) was used to excite the microstructures. Piezoresistive cantilevers with typical beam-proof mass structure were designed and fabricated for obtaining the vibration signal. For testing in harsh temperature environment, two instruments were designed to realize the low temperature environment and high temperature environment, respectively. A thermoelectric refrigerator was modified to vary the temperature of microstructures from room temperature down to -55 °C. A small alumina ceramics heater (MCH) was used to heat microstructures up to 350 °C. The base excitation device with PZT was also used to excite microstructures under harsh temperature environment. Laser Doppler Vibrometer (LDV) was adopted to obtain the vibration signals through the viewport of these instruments. The dynamic characteristics of silicon microcantilevers were tested under these harsh environment. The results show that the resonance frequencies of microcantilevers increase with the elevated external high load as soon as the deformation of micro-beam is in the geometrically nonlinear state, and also the resonance frequencies slightly and linearly decrease with the increasing temperature.