A 3-Axis MEMS Capacitive Accelerometer Free of Cross Axis Sensitivity

This paper describes integrated multi-axis MEMS capacitive accelerometer by using a set of vertical and horizontal electrodes. The proposed device has only one silicon proof mass which all detecting electrodes were located on it. 3-axis acceleration was detected by using a set of newly proposed movable and fixed, vertical and horizontal comb electrodes of different lengths. The structure employs capacitive transduction mechanism which provides high reliability, low temperature sensitivity, low drift, and low power consumption. It is introduced a new technique to eliminate the cross-axis sensitivity based on orientation and location of the electrodes. The proposed method is suitable for multi axis, acceleration detection systems such as automotive. The total sensing area for sensing all axis acceleration was 1.85 mm2. The ranges of measurable acceleration for in-plane (X and Y directions) and out plane (Z direction) are ±67g and ±18 g respectively. The resolution of all directions is 1g.