Characterization of Interfacial Oxide Layers in Heterostructures of Hafnium Oxides Formed on NH3-Nitrided Si(100)

概要

論文の詳細を見る
In the stack structures fabricated by NH3 nitridation of Si(100) at 650–700°C and subsequent electron-beam evaporation of HfO2, the blocking properties of ultrathin SiNx ($x={\sim}1.3$) upon oxidation in dry O2 ambient in the temperature range of 300–600°C have been studied by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared attenuated total reflection (FT-IR-ATR). Although the oxidation of Si(100) during O2 anneal is retarded using a ${\sim}1$-nm-thick SiNx layer grown by 700°C nitridation in NH3 ambient prior to the HfO2 evaporation, the surface oxidation of the ultrathin SiNx layer proceeds, accompanied by the movement of nitrogen atoms from the oxidized SiNx surface to the Si surface. As a result, the interfacial layer thickness is increased with no significant changes in nitrogen bonding features at the interface. From the temperature dependence of the interfacial oxide formation in the stack structure of HfO2 on thermally nitrided Si(100), we suggest that the control of O2 partial pressure is practically inevitable in suppressing completely the interfacial oxide growth at a thermal budget higher than 350°C.
2004-11-15