Abstract: Various embodiments of the present technology may provide a system and apparatus for reaction chamber. The system and apparatus may contain a reaction chamber having a spacer plate disposed between a lower chamber of the reaction chamber and a showerhead. An active heating element may be embedded within the spacer plate. A flow control ring, disposed adjacent to the spacer plate, is heated by conduction from the spacer plate heating element.

Abstract: A gas distribution system having a first plurality of apertures to supply a gas source to a reaction chamber and a second plurality of apertures surrounding the first plurality of apertures and configured to remove the gas from the reaction chamber. In one embodiment, the second plurality of apertures may gradually increase in diameter as the distance from a main exhaust channel increases. Alternatively, or in addition, the angle spacing between adjacent apertures may gradually decrease as the distance from the main exhaust channel increases.