Embodiments of process kits for use in a process chamber are provided herein. In some embodiments, a process kit for use in a process chamber includes a tubular body having a central opening configured to surround a substrate support, wherein sidewalls of the tubular body do not include any through holes; and a top plate coupled to an upper end of the tubular body and substantially covering the central opening, wherein the top plate has a gas inlet and has a diameter that is greater than an outer diameter of the tubular body, and wherein the tubular body extends straight down from the top plate.