Abstract: The disclosure relates to a method and apparatus for preventing extrusion or spiking of a metal atom from a metallization layer to other layers of a silicon wafer. In one embodiment, the method includes forming a silicon-on-ship device with a MEMS component on the substrate. The MEMS component may include one or more metal or metallic alloys. To prevent spiking from the MEMS component, the sides thereof can be coated with one ore more spacer or barrier layers. In one embodiment, oxygen plasma and thermal oxidation methods are used to deposit spacers. In another embodiment, an oxide layer is deposited over the wafer, covering the substrate and the MEMS component. Selective etching or anisotropic etching can be used to remove the oxide layer from certain regions of the MEMS and the substrate while covering the sidewalls. An amorphous silicon layer can then be deposited to cover the MEMS device.