Synthesis and Characterization of Tantalum Oxide Deposited By Metal-Organic Chemical Vapour Deposition (MOCVD)

Abstract

Tantalum oxide thin-films have rapidly evolved as a potentially important film material in a wide range of industrial applications such as optical coatings, dielectric films, corrosion and heat resistant coatings, dental implants and coronary stents, or prosthesis. The preparation of an improved liquid source metal-organic precursor suitable for the deposition of high-quality tantalum oxide thin films on soda-lime glass using Metal-organic Chemical Vapour Deposition (MOCVD) was reported. Peroxo–hydroxyl–amino tantalum complex precursor was prepared by a method of ligand-exchange reactions between hydroxo–peroxo tantalum complexes and traditional chelating reagents. Preparation of the thin-films was achieved by the pyrolysis of the precursor at four different temperatures (380 °C, 400 °C, 420 °C, 450 °C) with a flow rate of 1.5 dm3/min for 2 hours deposition period. The deposited films were characterized using Ultraviolet-Visible spectroscopy, Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray spectroscopy (EDX). A direct optical band gap of 4.16 eV – 4.70 eV was obtained from the analysis of the absorption spectrum of the thin-films. SEM micrographs revealed that the deposited film had no regular structure and the layers could be described as amorphous. The EDX results confirmed the presence of Tantalum and Oxygen in the thin-films.