ISS STUDY OF THE OXIDATION OF AU ON CU (300-A) THIN-FILMS

Using ISS techniques, composition versus depth profiles were made of Au (800 A) on Cu (300 A) films before and after heating in vacuum or 10. 6 kPa of oxygen at 163 degree , 202 degree , and 250 degree C for 10, 100, and 1000 minutes. Prior to heating, small amounts of Cu were found on the surface but not in the bulk of the gold. Heating the double layer film in vacuum at 250 degree C for 1000 minutes resulted in a homogeneous Au-Cu film. On the other hand, heating the double layer in oxygen produced an inverted structure wherein the Au was found to lie beneath a gold-free copper oxide overlayer (324 A).