Exchange-diffusion reactions in HfSiON during annealing studied by Rutherford backscattering spectrometry, nuclear reaction analysis and narrow resonant nuclear reaction profiling

HfSiON films deposited on Si (001) by reactive sputtering were submitted to rapid thermal annealing at 1000 °C in vacuum, N ₂ and O ₂ atmospheres. The stability of the dielectric was evaluated by measuring the atomic transport and exchange of the chemical species, using Rutherford backscattering spectrometry, nuclear reaction analysis and narrow resonant nuclear reaction profiling. Annealing in O ₂, ambient reduced the N concentration mainly from near-surface regions where oxygen was incorporated in comparable amounts. Vacuum annealing, on the other hand, induced N loss preferentially from the Si/dielectric interface and O loss preferentially from near-surface regions. The results are explained in terms of exchange-diffusion reactions occurring in the HfSiON.