Designing a new high performance 3-axis MEMS capacitive accelerometer

A new configured 3-axis MEMS capacitive accelerometer is presented in this paper. Single proof mass is employed to detect acceleration in three directions and acceleration could be measured in each axis independently. The new fully symmetrical configuration of the structure enables it to measure in plane and out plane directions by employing capacitive transduction method on a proof mass which leads to high reliable, less temperature sensitive, low drift and power accelerometer. So, it is more compatible with CMOS technology. The new comb drive configuration of electrodes eliminate the cross-axis sensitivity thoroughly. Thus, it is suitable for multi axis acceleration detection systems. The total sensing area, proof mass weight and detectable acceleration in all directions are 1.58 mm2, 12.1 µgr and 1 g, respectively. The acceleration measuring range in in plane direction (X and Y) is ±100 g and for out plane direction (Z) is ±30 g and surface micromachining method is proposed for fabrication process.