A method entails providing a substrate with a structural layer having a thickness. A partial etch process is performed at locations on the structural layer so that a portion of the structural layer remains at the locations. An oxidation process is performed at the locations which consumes the remaining portion of the structural layer and forms an oxide having a thickness that is similar to the thickness of the structural layer. The oxide electrically isolates microstructures in the structural layer, thus producing a structure. A device substrate is coupled to the structure such that a cavity is formed between them. An active region is formed in the device substrate. A short etch process can be performed to expose the microstructures from an overlying oxide layer.