Electrostatically driven linear micro-actuators: FE analysis and fabrication

Electrostatic actuators based on the principle of the parallel plate capacitor have been developed. In order to optimize the dssign, two- and three-dimensional electrostatic finite element (FE) analyses have been carried out. Both electroplating of gold and LPCVD of polysilicon in combination with dry etching (reactive ion etching (RIE)) have been applied to fabricate the structures using surface micromachining, Different actuator heights of 2 mu m (polysilicon) and 10 mu m (gold) have been realized. LTO (low-temperature oxide) served as the sacrificial layer, Four different stator electrode systems enable repeated forward and backward movements. Bearings fix the slider in the sideward direction, The maximum length af the slider movement depends only on the design. The slider length is about 1 mm, the width is 40 mu m. The gap between stator and slider electrodes is about 3.5 mu m.