The design, fabrication, and preliminary test results of a microelectromechanical, micromachined spatial light modulator (μSLM) with complementary metal-oxide semiconductor (CMOS) electronics, for control of optical phase is presented in this paper. An array of 32×32 piston-motion MEMS mirror segments make up the μSLM. Each mirror segment will be capable of altering the phase of reflected light by up to one wavelength for infrared illumination (? = 1.5 μm). The mirror segments are fabricated from metal in a low temperature process allowing for vertical integration of the μSLM with CMOS based, multi-bit, control electronics. The surface of the CMOS is planarized to facilitate μSLM-CMOS integration. The fabrication process and process development results, test results, including frequency response and electromechanical characterization of the (μSLM) actuators, will be presented.