Chemical phase transitions of the HfO2SiON/Si nanolaminate by high-temperature thermal treatments in NO and O2 ambient

Abstract

Temperature-dependent chemical phase transitions of the Hf O2 SiONSi (100) nanolaminate in O2 and NO ambient have been investigated using high-resolution photoemission spectroscopy. Hf 4f, Si 2p, O 1s, and N 1s photoemission spectra were measured after annealing the nanolaminate at a temperature between 750 and 1150 °C. These spectra show that the chemical phase transitions of the nanolaminate strongly dependend on the ambient gases. The nanolaminate in an O2 ambient is stable below 750 °C but the Hf O2 and SiON layers dissociate by producing Hf silicides above 950 °C. In contrast, the nanolaminate in NO ambient does not transit into Hf silicides up to 1050 °C. Interestingly, the Hf O2 and SiON layers transforms into Hf Ox Ny and Si Nx layers, respectively, with a high thermal stability, where the Hf Ox Ny layers are a high- k dielectric material and the Si Nx layers work as a barrier against both Si and O diffusion © 2005 American Institute of Physics.