Abstract: In some examples, a flat Bottom Shadow Ring (fBSR) is provided for processing a substrate in a processing chamber. An example fBSR comprises an overhang for covering an edge of the substrate in the processing chamber. The overhang includes a fiat zone that extends radially outward over the outer edge of the substrate.

Abstract: A gas delivery system configured to provide deposition and etch gases to a processing chamber for a rapid alternating process includes a first valve arranged to provide deposition gas from a deposition gas manifold to a first zone of a gas distribution device via a first orifice and provide the deposition gas from the deposition gas manifold to a second zone of the gas distribution device via a second orifice having a diameters than the first orifice. A second valve is arranged to provide etch gas from the etch gas manifold to the first zone of the gas distribution device via a third orifice and provide the etch gas from the etch gas manifold to the second zone of the gas distribution device via a fourth orifice having a different diameter than the third orifice.