Synthesis and characterization of Titanium Aluminium Nitride thin films deposited by thermal CVD and ion beam sputtering technique

Abstract

In the recent years Titanium Aluminium Nitride (Ti1-xAlxN) thin films have become a very popular coating material for bio-medical and manufacturing industries due to its higher hardness with a combination of high chemical inertness, higher resistance to oxidation and sound wear resistance. In the present study, Ti1-xAlxN single layer thin films have been deposited by using Atmospheric pressure chemical vapour deposition (APCVD) and Ion beam sputtering deposition (IBSD) technique by varying the precursor gas or the deposition temperature. The morphological, structural, compositional, electronic and mechanical properties have been investigated by scanning electron microscope (SEM)/field emission scanning electron microscope (FESEM), x-ray diffraction (XRD)/ grazing incidence x-ray diffraction (GIXRD), X-ray photo electron spectroscopy (XPS), X-ray absorption near edge structure (XANES) and Nano-indentation characterization techniques. The morphology of Ti1-xAlxN films prepared by APCVD technique at different process temperature and different N2 flow rate showed rough surface texture along with cracks and pores. However, Ti1-xAlxN coating prepared by using IBSD technique showed smooth coating surface over the substrate. XRD results confirmed the presence of dominant Ti1-xAlxN phases with face centered cubic (FCC) crystal structure. Ti1-xAlxN thin film coating deposited using CVD technique also indicated the presence of Al2O3 phases prepared with different N2 flow rate. The increase in FWHM of the diffraction peak with increase in N2 flow rate indicated grain structure refinement and higher plastic deformation. The XPS result reveals increase in Al % from 35 to 41.4 with increase in processing temperature and the Ti 2p, Al 2s, Al 2p, N 1s and O 1s spectra are observed at 458.7 eV, 119.3 eV, 75.2 eV, 396.9 eV and 534 eV binding energy (B.E) respectively. The XANES spectra of Ti1-xAlxN showed the N-k edges at 397.28 eV,398.68 eV and 400.32 eV, 402.23 eV and 405.28 eV corresponds to N-Ti, N-Al, N-N, N=N and N-O bonds.