Semiconductor systems and methods may include a semiconductor processing chamber having a gas box defining an access to the semiconductor processing chamber. The chamber may include a spacer characterized by a first surface with which the gas box is coupled, and the spacer may define a recessed ledge on an interior portion of the first surface. The chamber may include a support bracket seated on the recessed ledge that extends along a second surface of the spacer. The chamber may also include a gas distribution plate seated on the support bracket.