Influence of laser fluence and laser repetition rate on the synthesis of aluminium nitride thin films by nitrogen-ion-assisted pulsed laser deposition

Abstract

Aluminum nitride (AIN) thin films have been grown on Si(111) and Al 2 O 3 (001) substrates by pulsed KrF excimer laser (wavelength 248nm, duration 30ns) ablation of AIN target with assistance of nitrogen ion beam bombardment. The influence of process parameters such as laser fluence and laser repetition rate has been investigated to obtain high quality AIN films. The XRD spectra of AIN films on Si(111) and Al 2 O 3 (001) substrates yield full-width-half- maximum (FWHM) values of approximately 2.1-1.7 degree(s). The chemical composition of the films is characterized by X-ray photoelectron spectroscopy (XPS). The surface morphology of the films is measured by atomic force microscope (AFM). Al 2 O 3 (0001) substrate shows better matching with the AIN films since highest crystallite size can be achieved among the different type of substrates evaluated. Better quality AIN films (with bigger crystallite size) can be achieved with higher laser fluence of 6J/cm 2 and an optimum laser repetition rate 7Hz.