A novel piezoresistive accelerometer for high accuracy and overload ability [MEMS device]

This paper presents the design and simulation of a novel acceleration sensor with high accuracy and overload ability. A super-stable structure with quad-beams, which has a highly symmetric structure has been designed, and this helps to eliminate the errors caused by the change of the dimensions and position of the piezoresistors in the structure. At the same time, this structure induces films between the beams to reduce the cross-axis sensitivity. Some holes are made in the films to reduce the vertical rigidity. Thus, the films have little effect on the sensitivity. Besides, a sandwich structure is adopted. In this device, the damping of the device is controlled by adjusting the clearances between the caps and the seismic mass which can obtain a large bandwidth and good frequency response. Bumps are made on two of the caps to get high overload ability. The piezoresistors are covered with a metal layer to improve the electric performance. This structure is beneficial for high resolution, low cross-axis sensitivity, high overload and good electric performance of the device.