Abstract
TiN films have many useful properties such as extreme high microhardness, resistance to wear, resistance to friction, and so on. However, relatively poor resistivity against oxidation is shown at high temperature. The purpose of this work is to investigate the oxidation behavior of the AlN/TiN double layer films as an alternative to TiN films.
TiN single layer films (thickness; 300 nm) and AlN(100 nm)/TiN(200 nm) double layer films were deposited onto (001) Si wafers using rf reactive sputtering apparatus with two planar magnetron type cathodes. The targets were pure Ti (>99.9%) and pure Al (>99.999%) disks (70 mm in diameter). An Ar+N2 mixed gas (Ar:N2=1:1, total pressure 0.4 Pa) was used as the sputtering gas. The substrate temperature and rf power were kept constant at R.T. and 300 W, respectively. The deposited films were annealed in the air environment at 400∼700°C for 60 min and then subjected to Auger depth profiling.
The as-deposited AlN/TiN interface appeared to be free from contamination and interdiffusion. There was no evidence of the existence of compound formation at the interface. X-ray diffraction analysis revealed that the AlN crystalline layer had an 00·2 preferred orientation on the weakly 001 oriented TiN layer. The oxide layer of ∼200 nm was formed on the TiN single layer films by annealing at 600°C for 60 min. On the contrary, the AlN/TiN double layer films showed excellent oxidation resistance even when annealing at 700°C.
