A method for forming a conformal, homogeneous dielectric film includes: forming a conformal dielectric film in trenches and/or holes of a substrate by cyclic deposition using a gas containing a silicon and a carbon, nitrogen, halogen, hydrogen, and/or oxygen, in the absence of a porogen gas; and heat-treating the conformal dielectric film and continuing the heat-treatment beyond a point where substantially all unwanted carbons are removed from the film and further continuing the heat-treatment to render substantially homogeneous film properties of a portion of the film deposited on side walls of the trenches and/or holes and a portion of the film deposited on top and bottom surfaces of the trenches and/or holes.