The surface roughness of epitaxially grown 3C-SiC films is a key factor affecting the fabrication and performance of SiC-based nanoelectromechanical systems. This paper presents the results of a study on adjusting key deposition process parameters to control surface roughness of 3C-SiC films during film growth. For 3C-SiC films grown using a conventional three-step, carbonization-based, atmospheric pressure chemical vapor deposition process, the surface roughness depends on the precursor gas flow rates during both the carbonization and film growth steps. By optimizing the carbonization and the film growth steps with respect to surface roughness, an average surface roughness of 1.5 nm for a 50 nm thick 3C-SiC film was achieved. (C) 2004 The Electrochemical Society.