A Novel Out-of-Plane Accelerometer with Fully-Differential Sensing Circuit and Sub-Micron Gap

This study presents a novel CMOS out-of-plane linear accelerometer. This capacitance type out-of-plane accelerometer contains special designed gap-closing sensing electrode arrays with fully differential sensing circuits. Moreover, this study established a post-CMOS wet-etching process to realize a sub-micron sensing-gap between stationary and moving electrodes in the out-of-plane direction. Thus, the sensing capacitance can be significantly increased for high fill-factor of sensing-electrode and the sub-micron sensing gap. The measurement results demonstrate that the present out-of-plane accelerometer has a sensitivity of 0.8 mV/g, and a non-linearity of 2.43%.