Method and structure for fabricating smooth mirrors for liquid crystal on silicon devices

A liquid crystal on silicon (LCOS) device, the device comprising:

• a semiconductor substrate;
• a metal-oxide semiconductor (MOS) device layer overlying the semiconductor substrate, the MOS device layer having a plurality of MOS devices;
• a planarized interlayer dielectric layer overlying the MOS device layer;
• a plurality of recessed regions formed within a portion of the planarized interlayer dielectric layer;
• an aluminum layer filling each of the recessed regions to form a plurality of respective electrode plates corresponding to each of the recessed regions, the aluminum layer having a smooth surface free from any dimple, each of the electrode plates being coupled to each one of the MOS devices;
• a protective layer of only an aluminum oxide layer directly overlying a surface of each of the plurality of electrode plates, the protective layer formed by exposing the electrode plates to an oxidizing fluid;
• a liquid crystal film directly overlying the protective layer;
• and
• a mirror finish formed on the surface of each of the electrode plates for reflecting light by a chemical mechanical polishing process, the mirror finish being substantially free from dishes and scratches.