Topotaxial growth of Ti2AlN by solid state reaction in AlN/Ti(0001)multilayer thin films

The formation of Ti2AlN by solid state reaction between layers of wurtzite-AlN and alpha-Ti was characterized by in situ x-ray scattering. The sequential deposition of these layers by dual magnetron sputtering onto Al2O3 (0001) at 200°C yielded smooth, heteroepitaxial (0001) oriented films, with abrupt AlN/Ti interfaces as shown by x-ray reflectivity and Rutherford backscattering spectroscopy. Annealing at 400°C led to AlN decomposition and diffusion of released Al and N into the Ti layers, with formation of Ti3AlN. Further annealing at 500°C resulted in a phase transformation into Ti2AlN(0001) after only 5 min.