This invention discloses a MEMS device supported on a substrate formed with electric circuit thereon. The MEMS device includes at least an electrode connected to the circuit and at least a movable element that is controlled by the electrode. The MEMS device further includes a conformal protective layer over the electrode and the circuit wherein the protective layer is semiconductor-based material. In a preferred embodiment, the MEMS device is a micromirror and the semiconductor material is one of a group of materials consisting of Si, SiC, Ge, SiGe, SiNi and SiW.