The authors report on the inflexion behaviour of the flatband voltage (VFB) while increasing the oxide thickness in HfO2-based capacitors. VFB initially showed a significant shift and then remained nearly constant on increasing the HfO2 or SiO2 thickness. It was explained that this result was probably due to the existence of an oxygen vacancy in HfO2 films, which was supported by X-ray photo-emission spectroscopy and electrical measurements. Additionally, the oxygen vacancy also seemed highly related to the formation of an interfacial dipole at the HfO2/Si interface.

Inflexion Behaviour of VFB While Tuning the Oxide Thickness in HfO2-Based Capacitors. R.Jiang, Z.Li, Y.Zhang: Journal of Physics D, 2010, 43[16], 165302