The micro-electromechanical (MEMS) actuator comprises a hot arm member and a cold arm member. The cold arm member comprises at least two longitudinally spaced-apart flexors. The actuators may also be constructed with at least one among the hot arm member and the cold arm member comprising at least one spring section. The stress in this improved MEMS actuator is more uniformly distributed, thereby reducing the mechanical creep and improving its reliability as well as its operation life.