Vacuum CVD chambers are disclosed which provide a more uniformly deposited thin film on a substrate (14). The chamber susceptor mount (210) for the substrate (14) is heated resistively with a single coil firmly contacting the metal of the susceptor on all sides, providing uniform temperatures across the susceptor mount (210) for a substrate (14). A purge gas line (222) is connected to openings in the susceptor outside of the periphery of the substrate (14) to prevent edge and backside contamination of the substrate (14). A vacuum feed line mounts the substrate to the susceptor (210) during processing. A refractory purge guide (226), or a plurality of placement pins, maintain a fixed gap passage for the purge gases to pass alongside the edge of the wafer (14) and into the processing area of the chamber. An exhaust pumping plate improves the uniformity of exhaustion of spent gases from the chamber.