An MEMS mirror structure is formed using an etching process that forms sidewall oxide spacers while maintaining the integrity of the oxide layer formed over the reflective layer of the MEMS mirror structure. The discrete mirror structure is formed to include a reflective layer sandwiched between oxide layers and with a protect layer formed over the upper oxide layer. A spacer oxide layer is formed to cover the structure and oxide spacers are formed on sidewalls of the discrete structure using a selective etch process that is terminated when horizontal portions of the spacer oxide layer have cleared to expose the release layer formed below the discrete mirror structure and the protect layer. The superjacent protect layer prevents the spacer oxide etch process from attacking the upper oxide layer and therefore maintains the integrity of the upper oxide layer and the functionality of the mirror structure.