Interface states for HfO2/Si structure observed by x-ray photoelectron spectroscopy measurements under bias

A 1.0 nm silicon nitride (SiN) layer can prevent reaction between HfO2 and Si completely. In this case, the interface state spectra obtained from x-ray photoelectron spectroscopy measurements under bias have two peaks above and below the midgap, attributable to Si dangling bonds interacting weakly with an atom in SiN, indicating a high atomic density of the SiN layer. When a HfO2 layer is deposited on a 1.0 nm SiO2 layer, the SiO2 thickness increases to 1.6 nm. For this structure, one interface state peak is present near the midgap, attributable to isolated Si dangling bonds, indicating a low atomic density. (c) 2006 American Institute of Physics.