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.