Embodiments of the invention provide apparatuses and methods for depositing materials on substrates during vapor deposition processes, such as atomic layer deposition (ALD) . In one embodiment, a chamber contains a chamber lid (832) containing an expanding channel (834) formed within a thermally insulating material (838) either directly within the chamber lid or formed within a funnel liner attached thereon. The chamber further includes at least one conduit (841 a-d) coupled to a gas inlet within the expanding channel and positioned to provide a gas flow in a circular direction, such as a vortex, a helix or a spiral. The chamber may contain a retaining ring (819), an upper process liner (822), a lower process liner (824) or a slip valve liner (826) . Liners usually have a polished surface finish and contain a thermally insulating material such as fused quartz or ceramic. In an alternative embodiment, a deposition system contains a catalytic water vapor generator connected to an ALD chamber.