Chemical interface analysis of as grown HfO[sub 2] ultrathin films on SiO[sub 2]

The quality of the interface between a HfO2 high-k gate dielectric and the Si substrate directly influences its electrical properties. The chemical composition of the interfacial region of HfO2 deposited on a SiO2/Si(100) substrate by pulsed liquid injection metal organic chemical vapor deposition at 430 and 550 °C was investigated by medium energy ion scattering, angular resolved x-ray photoemission spectroscopy analysis, and high resolution transmission electron microscopy. It is shown that the HfO2/SiO2 interface is abrupt with low roughness and no silicate. The interface roughness with SiO2 is found to be close to that generally measured in silicon technology (silicon oxide above silicon substrates) [ E. A. Irene, Solid-State Electron., 45, 1207 (2001) ]. The analysis of the experimental results indicates that the deposition technique does not lead to the formation of an extended silicate layer at the HfO2/SiO2 interface