FEM Based Design and Simulation of Bulk Micromachined MEMS Accelerometers with Low Cross Axis Sensitivity

This paper reports the design and simulation of two MEMS piezoresistive accelerometers for single axis low g (plusmn2g) automotive applications. Both the accelerometer structures consist of four beams at the top with eight embedded resistors as sensing elements to form Wheatstone bridge network and interconnected to minimize the cross axis sensitivity. FEM based design and simulation results for both the accelerometers are presented and compared, which are performed using commercially available MEMSCAD tool CoventorWarereg. Fabrication process and technological aspects to realize both the structures are discussed. The sensitivity of the two accelerometers is 6.5 mV/g and 5.85 mV/g respectively. Cross axis sensitivity of the structures is three orders lower than the prime axis sensitivity