Sodium is removed from silicon wafer surfaces by a vapor phase method utilizing the chelation compound 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (H+ hfac). At a total pressure of 7.6 Torr, sodium is removed from the wafer surface at temperatures above 190 degrees C. Several mechanisms may play a role in the reaction of H+ hfac with surface sodium species. (C) Air Products and Chemicals, Inc. - 1998.