Dielectric constants and phonon modes of amorphous hafnium aluminate deposited by metal organic chemical vapor deposition

Authors

C. Bundesmann, Leibniz-Institut für Oberflächenmodifizierung e.V., 04318 Leipzig, Germany and Institut für Experimentelle, Physik II, Universität Leipzig, 04103 Leipzig, Germany
O. Buiu, University of Liverpool, Liverpool L69 3GJ, United Kingdom
S. Hall, University of Liverpool, Liverpool L69 3GJ, United Kingdom
Mathias Schubert, University of Nebraska - LincolnFollow

Date of this Version

2007

Comments

Published in Appl. Phys. Lett. 91, 121916 (2007). Copyright © 2007 American Institute of Physics. Used by permission.

Abstract

Dielectric constants and long-wavelength optical phonon modes of amorphous hafnium aluminate films with a maximum aluminum content of 19 at. % are studied by infrared spectroscopic ellipsometry (IRSE). The hafnium aluminate films were prepared by metal organic chemical vapor deposition on silicon substrates. IRSE revealed one polar lattice mode and one impurity-type mode, which show all a systematic shift in frequency with varying Al content. The static dielectric constant decreases from 10.1 for 4.6 at. % Al to 8.1 for 19 at. % Al. The absolute values were found to be between 50% and 70% smaller than the values obtained from electrical measurements.