Patent ID: 8100081

Claim:
An apparatus comprising: a substrate support, wherein the substrate support includes a support region and wherein the support region includes an interior portion and a peripheral portion; a showerhead comprising: (i) an inner channel configured to direct a purge gas toward the interior portion of the support region, the inner channel comprising an outlet; (ii) an outer channel configured to direct plasma species toward the peripheral portion of the support region, the outer channel comprising an outermost wall and having an outermost diameter; (iii) a barrier oriented substantially parallel to the substrate support and coextensive with most of the support region, wherein the barrier has an outermost diameter less than the outermost diameter of the outer channel; (iv) a non-barrier region disposed between the barrier and the outermost wall of the outer channel providing an unobstructed flow path from the outer channel towards the support region of the substrate support; and (v) a deflector angled with respect to the barrier and substrate support, wherein the deflector is interposed between the non-barrier region and the outlet, wherein the inner channel is configured to have no more than a single exit orifice through the barrier for gas flow towards the interior portion of the support region.