sputter etching the surface of said substrate with {HEAD ~ energetic gas ions} to remove traces of residual hydrocarbon and to preferentially reduce {TAIL ~ the concentration} of alkali metal atoms and alkali metal oxides at the substrate surface 
to preferentially reduce
sputter etching the surface of said substrate with { HEAD ~ energetic gas ions } to remove traces of residual hydrocarbon and to preferentially reduce { TAIL ~ the concentration } of alkali metal atoms and alkali metal oxides at the substrate surface
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH