The interface of atomic layer deposited Al2O3 on silicon
|Kunyuan Gao 1, Florin Speck 1, Konstantin Emtsev 1, Thomas Seyller 1, Lothar Ley 1, Michael Oswald 2, Walter Hansch 2|
1. Universität Erlangen-Nürnberg, Institut für Technische Physik II, Erwin-Rommel-Str. 1, Erlangen 91058, Germany
Al2O3 films 1.5nm to 20nm thick were deposited as alternative high k gate dielectric on hydrogen-terminated silicon by Atomic Layer Deposition (ALD) technique and characterized by Synchrotron X-ray Photoelectron Spectroscopy (SXPS), Fourier Transform Infrared (FTIR) absorption spectroscopy and admittance measurements. The SXPS results indicate that about 60% of Si-H bonds are preserved at the Al2O3/Si interface and this is confirmed by monitoring the Si-H stretching modes by FTIR spectroscopy in the Attenuated Total Reflection (ATR) mode both before and after ALD of Al2O3. The remaining 40% of Si-H bonds are replaced by Si-O bonds as verified by SXPS. In addition, a fraction of a monolayer of SiO2 formed on top of the Al2O3 dielectric during deposition. The presence of OH groups at a level of 3% of the total oxygen content was detected throughout the Al2O3 layer through a chemically shifted O1s component in SXPS. Admittance measurements give a satisfactorily high dielectric constant of 9.12, but a relatively high density of interface traps between 1011 and 1012cm-2eV-1.
Presentation: oral at E-MRS Fall Meeting 2005, Symposium F, by Kunyuan Gao
See On-line Journal of E-MRS Fall Meeting 2005
Submitted: 2005-05-17 17:40 Revised: 2009-06-07 00:44