Thermal stability of nitrogen incorporated in $HfNxOy$ gate dielectrics prepared by reactive sputtering

In this letter, we report the thermal stability of nitrogen incorporated in $HfOxNy$ gate dielectrics prepared by reactive sputtering using x-ray photoelectron spectroscopy, secondary ions mass spectrometry, and electrical characterization. The results indicate that the bulk Hf–N bonds in reactive-sputtered $HfOxNy$ are not stable during the postdeposition annealing and can be easily replaced by oxygen, resulting in significant loss of nitrogen from the bulk film. However, N at the $HfOxNy/Si$ interface forms N–Si bonds, contributing to the excellent electrical stability of reactive sputtered $HfOxNy$ gate dielectrics during the post deposition annealing.