Methods for forming thin films in high aspect ratio feature definitions are provided. In one implementation, a method of processing a substrate in a process chamber is provided. The method comprises flowing a metal organic containing precursor gas comprising a ligand into an interior processing volume of a process chamber, flowing a precursor gas comprising the ligand into the processing volume and thermally decomposing the metal-containing precursor gas comprising the ligand and the precursor gas comprising the ligand in the interior processing volume to deposit a metal-containing layer over at least one or more sidewalls and a bottom surface of a feature definition in and below a surface of a dielectric layer on the substrate.