title: Electron energy-loss spectroscopy study of thin film hafnium aluminates for novel gate dielectrics.
abstract: We have used conventional high-resolution transmission electron microscopy and electron energy-loss spectroscopy (EELS) in scanning transmission electron microscopy to investigate the microstructure and electronic structure of hafnia-based thin films doped with small amounts (6.8 at.%) of Al grown on (001) Si. The as-deposited film is amorphous with a very thin (approximately 0.5 nm) interfacial SiOx layer. The film partially crystallizes after annealing at 700 degrees C and the interfacial SiO2-like layer increases in thickness by oxygen diffusion through the Hf-aluminate layer and oxidation of the silicon substrate. Oxygen K-edge EELS fine-structures are analysed for both films and interpreted in the context of the films' microstructure. We also discuss valence electron energy-loss spectra of these ultrathin films.
authors.affiliation: Materials Department, University of California, Santa Barbara 93106-5050, USA. stemmer@mrl.ucsb.edu
authors.forename: S
authors.initials: S
authors.lastname: Stemmer
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Chen
authors.forename: W J
authors.initials: WJ
authors.lastname: Zhu
authors.forename: T P
authors.initials: TP
authors.lastname: Ma