Investigation of substoichiometric titanium nitride grown by unbalanced magnetron sputtering

TiNx (stoichiometric factor, x=0.1-0.4) films were deposited at a substrate temperature typically of 480 degreesC using an industrial-sized multi-targ et PVD coating machine. The stoichiometric factor, x, depended on the manne r of substrate rotation as well as the reactive gas flow during depositing. In parallel, multiphase compositions of alpha Ti(N), epsilon Ti2N and delt a TiN were found with hardness values varying from 1500 to 2300 Hk, and 210 0 Hk for epsilon phase Ti2N. The XRD spectral showed Bragg reflections asso ciated with mixed phase compositions. The almost pure epsilon Ti2N phase wa s found in the film with x close to 0.34 and the XRD diffraction pattern of this film perfectly matched the epsilon phase documented as referred to in the JCPDS file 17-386. SEM and TEM cross-sections exhibited a very fine gr ain structure for films containing dominant epsilon Ti2N phase. The microst ructure of epsilon Ti2N him was extremely homogeneous throughout the comple te film growth. The surface of epsilon Ti2N him was surprisingly smooth. (C ) 2000 Elsevier Science B.V. All rights reserved.