A comparison of defect states in tantalum pentoxide (Ta2O5) films after rapid thermal annealing in O2 or N2O by zero-bias thermally stimulated current spectroscopy

Abstract

The concentration of shallow defect states in Ta2O5 films was found to be greatly reduced, resulting in much less leakage current in Al/Ta2O5/Si capacitors, if N2O was used instead of O2 for post-deposition annealing. The superiority of N2O is explained by the formation of a slightly thicker SiOx diffusion barrier, which can reduce Si contamination coming from the Si substrate into the Ta2O5 film.