Structure and composition of TixAl1−xN thin films sputter deposited using a composite metallic target

An original composite target configuration with various STi/(STi+SAl) area ratios was used to prepare hard TixAl1−xN thin films by r.f. reactive magnetron sputtering. The crystallographic structure of the films deposited on high-speed steel and glass substrates was determined by X-ray diffraction. Homogeneity was investigated from compositions and depth profile measurements carried out by Rutherford backscattering spectroscopy, electron probe microanalysis and glow discharge optical emission spectroscopy. The modulation of the Ti and Al area ratios of the target produced changes of the structure from the fcc TiN to the hexagonal AlN phase and simultaneously, a gradual modification of the TixAl1−xN metal concentration from x=0 to 1. The mechanical behaviours such as hardness and scratch tests were also determined and correlated with the evolution of the structural and compositional properties.