Secondary electron yield and Auger electron spectroscopy measurements on oxides, carbide, and nitride of niobium

Abstract

Secondary electron yield measurements before and after Ar ion sputter cleaning were made on Nb and Nb compounds of interest for rf superconducting cavities. Total secondary electron yields (σ) for primary energies 20–1500 eV were measured for solid Nb (σmax=1.3 at 300 eV), anodized Nb2O5 (σmax=1.2 at 300 eV), and powders of Nb(σmax=1.0 at 400 eV), NbO (σmax=0.9 at 400 eV), NbO2 (σmax=1.0 at 400 eV), Nb2O5 (σmax=0.95 at 400 eV), NbC(σmax=0.8 at 400 eV), and NbN (σmax=0.8 at 500 eV). Determinations were made for Auger elemental sensitivities, and the relationship between Auger peak heights and oxide stoichiometry is discussed. The sputter etch rate of anodized Nb2O5 was measured by depth profiling anodic coatings of known thickness.