Electrical properties of HfTiO gate-dielectric metal oxide semiconductor capacitors with NO and N2O surface nitridations

In this paper, Si-MOS capacitors with HfTiO/SiON stack gate dielectric were fabricated by using Si-surface thermal passivation in NO and N₂O ambients respectively and reactive co-sputtering technology. Results show that the sample pretreated in NO ambient has excellent interface properties, low gate leakage current density and high reliability. This is attributed to the formation of a SiON interlayer with suitable proportion of N and O, and N-barrier role of isolating Ti in HfTiO from Si of the substrate, thus effectively preventing the inter-diffusions of Ti and Si during post-deposition annealing.