cf 4 gas an example oxygen plasma system 100 includes a gas source 110 configured to deliver the gas mixture 112 in an example the gas source 110 includes an o 2 gas source 110 a and a cf 4 gas source 110 b that are operably connected so that the two gases can be mixed to form the gas mixture 112 in another example the gas source 110 includes a single gas source that includes the gas mixture 112 the gas source 110 is pneumatically coupled to an input end 122 of a plasma tube 120 the plasma tube 120 also has an output end 123 an outer surface 124 and an interior 126 an example plasma tube 120 is made of quartz and is substantially cylindrical other known materials can be used for plasma tube 120 a radio frequency rf coil 130 resides around the outer surface 124 of plasma tube 120 and is operably connected to an rf source 134 that includes an rf matching network the re ald system 10 includes a number of valves 150 to control the flow of the precursor gas 52 the inert gas 62 as a purge gas the gas mixture 112.