Embodiments of the present disclosure generally relate to a processing chamber for conformal oxidation of high aspect ratio structures. The processing chamber includes a chamber body with a first side and a second side opposite the first side, and a flow assembly disposed in the first side. The flow assembly includes a flow divider to direct fluid flow away from a center of a substrate disposed in a processing region of the processing chamber. The flow divider includes a crescent shaped first side, a top, and a bottom. The processing chamber also includes a distributed pumping structure located adjacent to the second side. The flow assembly is designed to reduce flow constriction of the radicals, leading to increased radical concentration and flux.