Dual gas feed showerhead for deposition

A showerhead utilized within a process chamber includes a first inlet for receiving a first gas from a first source at a center region of an inner plenum defined therein. A plurality of second inlets is defined along a peripheral region of the showerhead for receiving a second gas from a second source. A plurality of conduits couples the edge plenum to an outer edge of the inner plenum so as to supply the second gas to the inner plenum. The first gas creates an inner flow that flows radially outward from the center region to an outer edge of the inner plenum and the second gas supplied by the edge plenum creates a perimeter flow that flows inward from the outer edge of the inner plenum toward the center region. A stagnation point defining an adjustable radius is formed at an interface of the first gas and the second gas. A plurality of outlets are defined across a lower surface of the showerhead and extends a diameter of the inner plenum such that the first gas from the inner flow exits the plurality of outlets from the center region up to the stagnation point and the second gas from the perimeter flow exits the plurality of outlets from the stagnation point to the outer edge.