Detection of surface nitrogen in high-T c Nb3Ge films by Auger analysis

Auger electron spectroscopy was applied to Nb3Ge films that possessed Tc’s above 20 K. The surface composition was determined from the Auger spectra. A considerable amount of nitrogen was detected on the surface. This amount, which varied by a factor of 3 across the surface, was 100 times higher than the nitrogen concentration in the film. The discrepancy is tentatively assigned to the effect of argon-ion sputter cleaning prior to the Auger measurements.