Structural properties of AIN films deposited by plasma-enhanced atomic layer deposition at different growth temperatures

Abstract

Crystalline aluminum nitride (AlN) films have been prepared by plasma-enhanced atomic layer deposition (PEALD) within the temperature range from 100 to 500 °C. A self-limiting, constant growth rate per cycle temperature window (100-200 °C) was established which is the major characteristic of an ALD process. At higher temperatures (>225 °C), deposition rate increased with temperature. Chemical composition, crystallinity, surface morphology, mass density, and spectral refractive index were studied for AlN films. X-ray photoelectron spectroscopy (XPS) analyses indicated that besides main Al-N bond, the films contained Al-O-N, Al-O complexes, and Al-Al metallic aluminum bonds as well. Crystalline hexagonal AlN films were obtained at remarkably low growth temperatures. The mass density increased from 2.65 to 2.96 g/cm 3 and refractive index of the films increased from 1.88 to 2.08 at 533 nm for film growth temperatures of 100 and 500 °C, respectively. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.