Investigation and simulation on the dynamic shock response performance of packaged high-g MEMS accelerometer versus the impurity concentration of the piezoresistor

摘要

To enhance the stability of packaged high-g MEMS accelerometers with double cantilevers positioned asymmetrically, the dynamic shock responses of components versus impurity concentration of piezore-sistors at various working temperatures have been probed by using Finite Element Method (FEM). Results indicate that the dynamic output responses of component are actually the superposition of the forced vibrations with dynamic shock and those of cantilevers in their eigenfrequency. The dynamic responses of components are sensitive to the working temperature. With the increase of working temperature, the inherent frequency vibrations of the cantilevers are depressed gradually. Moreover, the larger the difference between the working temperature and reference temperature, the more obvious the impurity effect of piezoresistors is. The difference between the peak output voltage of response under 1 × 10~(18) cm~(-3) and that under 1 × 10~(21) cm~(-3) varies greatly from -2.2146 mV at T= 0 ℃ to 8.6609 mV at T= 100 ℃, of course, is partly due to the characteristic variation of damping media under various working temperatures. Therefore, to improve the stability of component and further weaken the impurity concentration effect and the temperature effect of piezoresistors on the performance of components, it is necessary to increase the impurity concentration of piezoresistors and keep the components working at relatively lower temperature only if the electro-performance of component is satisfied.