Electrostatic deformable devices using surface micromachining

Two types of electrostatic deformable devices were fabricated by using silicon surface micromachining techniques. Micro-bridge structures and deformable micro-mirror devices (DMDs) have been designed and tested. The microelectromechanical structures (MEMS) are based on the electrostatic attractive force between two polysilicon layers. Testing results in general showed agreement with the theoretical modeling for the two structures. In addition, from testing of the micro-bridge structures it was found that the manner in which a voltage was applied to the structures was very important. A sudden application of voltage greater than the experimentally determined static dielectric breakdown voltage caused the micro-bridges to fracture before the dielectric material had the opportunity to respond on breakdown. Fracturing of the structures was due to the resulting internal stresses that occur near the fixed ends of the bridge caused by electrostatic attraction.