Disclosed herein is a heat shield assembly for a processing chamber. The processing chamber includes a body having sidewalls, a bottom and a lid that define an interior volume. The heat shield assembly is disposed in the interior volume, and includes a heat shield and a preheat member. The preheat member includes an inner circumference, and is positioned below the heat shield. A susceptor is disposed in the interior volume and configured to support a substrate, and is positioned within the inner circumference of the preheat member. An opening is positioned between the susceptor and the preheat member. A first section of the opening is proximate to a gas inlet, and is covered by the heat shield. A second section of the annular opening is proximate a gas outlet, and is not covered by the heat shield member.