In a plasma processing apparatus, a showerhead is provided that allows for selective ionization of one or more process gasses within the showerhead. The showerhead allows the gasses to react after they exit the showerhead. As a result, a greater volume of materials are. available for deposition on a wafer surface during a chemical vapor deposition process than would be available in a process that remotely generates plasma. In addition, less damage is done to the wafer that would be done in a process that generates plasma next to the wafer.