AN ACCELEROMETER MADE IN A 2-LAYER SURFACE-MICROMACHINING TECHNOLOGY

A microaccelerometer has been fabricated in surface-micromachining tec hnology and is designed to work in the 50g range. An important advanta ge of this type of sensor is that only two polysilicon layers are need ed. Nevertheless, the sensor works as a differential capacitor and can also be driven in a force-balanced mode. Compared to laterally driven structures, the technological steps are less critical. The typical ba ndwidth of the structure is approximately 3 kHz. The overall change in capacitance is 13 fF. In order to calculate the critical damping and to reduce deformation of the mass, simulations have been carried out.