Concentric showerhead for vapor deposition

Embodiments of the invention generally relate to a concentric gas manifold assembly used in deposition reactor or system during a vapor deposition process. In one embodiment, the manifold assembly has an upper section coupled to a middle section coupled to a lower section. The middle section contains an inlet, a manifold extending from the inlet to a passageway, and a tube extending along a central axis and containing a channel along the central axis and in fluid communication with the passageway. The lower section of the manifold assembly contains a second manifold extending from a second inlet to a second passageway and an opening concentric with the central axis. The tube extends to the opening to form a second channel between the tube and an edge of the opening. The second channel is concentric with the central axis and is in fluid communication with the second passageway.