Optical phonon lifetimes in sputtered AlN thin films

Abstract

We study the vibrational properties of AlN thin films deposited on silicon (100) substrates by the reactive DC-pulsed magnetron sputtering. The frequencies and lifetimes of the E-1(TO) and A(1)(LO) optical phonons are calculated from Fourier transform infrared spectra using the factorized model of a damped oscillator. We analyze the structural properties by the x-ray diffraction technique to correlate the elongation of phonon lifetimes with increasing film thickness. The lifetimes of the phonon modes in AlN thin films are compared to the values in a single crystal. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4711773]