Deformation induced by residual stress during deposition process of lateral motion micro electrothermal actuators

Lateral motion micro thermal actuator is one of an important actuator for its large deformation and driving force. The lateral motion electrothermal actuator is often fabricated by surface micromachining. The out of plane deformation would be induced by residual stress, due to mismatch of thermal expansion coefficients between structure and sacrificial layers.Such deformation has advantage to overcome sticking problem during removing sacrificial layer by wet etching. From experiment results, the maximum deformation value depends on structure layer thickness and doping density. It can be considered the annealing process can diminish most residual stress in cold beam.