Electrostatic sensor for the detection of residual charges on MEMS devices

Electrostatic force and capacitance play an important role in Micro-electromechanical systems (MEMS). These systems consist of micromechanical components along driving and detection electrodes. The necessary electrodes are placed on insulating materials and in some cases they are coated with an insulating layer. It has been observed that after electrical breakdown in the air gap or the contact of the movable element with dielectric layer the characteristics of the MEMS devices has changed. This is caused by charge deposition on the insulating material and leads to an additional offset voltage. Hence it is very important to investigate the behavior of charges in MEMS devices to derive rules for the design and the fabrication process. The article presents a novel electrostatic field sensor realized using a micromechanical component. It was developed to characterize surface charges on dielectric layers mainly in the region of electrode structures.