Substrate Effects on the APCVD Growth of Titanium Nitride Films

Abstract
Titanium nitride thin films were deposited by atmospheric chemical vapour deposition in the temperature range 560°C to 660°C from titanium tetrachloride and ammonia in argon carrier gas and studied in terms of nucleation and growth, crystalline orientation and impurities. The films were deposited in a cold wall, atmospheric pressure CVD reactor designed to encourage laminar flow conditions and accommodate a number of different substrates under similar temperature and mass transport conditions. Characterisation of the films using scanning electron and atomic force microscopy showed an increase in nucleation density and decrease in surface roughness with temperature. Glancing-angle X-ray diffraction determined the crystallinity and orientation of the films with respect to the substrate and deposition temperature. Films deposited on Si₃N₄ showed preferred orientation whereas those on glass showed random orientation. Energy dispersive spectroscopy calibrated by Rutherford backscattering spectroscopy indicated that the amount of chlorine and oxygen contamination decreased with increasing temperature. RBS also determined the stoichiometry of the titanium nitride films. Resistivity and optical studies were also carried out on titanium nitride thin films on glass to evaluate their suitability as heat mirrors.