Numerical-experimental comparison of low-g and high-g tests on a polysilicon MEMS accelerometer

In this work in-situ measurements obtained during low-g and high-g experiments (g being the gravity acceleration), carried out on a polysilicon inertial accelerometer mounted on a PCB-board, are compared with numerical simulations. Tests are carried out at accelerations ranging between 90 and 5500 g. In each test not only the shock waveform and the device response are recorded, but also the MEMS performance is checked. The shock tests are carried out on a device attached on the top of a falling cylinder in a drop testing machine, where the shock impulse is sensed by a quartz accelerometer mounted next to the tested device. The quartz accelerometer output signal is used as input for the numerical analysis at the MEMS length-scale. A three dimensional, finite element model of the packaged sensor is adopted to simulate its mechanical response in the transient regime. Therefore, a comparison with the experimentally measured output voltage of the tested MEMS allows to single out the effects of mechanical nonlinearities.