Reactive chemical vapor deposition of heteroepitaxial Ti1-xAlxN films

Processing of Ti1-xAlxN thin films by the reactive chemical vapor deposition (R-CVD) technique has been performed from the reaction between a titanium tetrachloride (TiCl4-H-2) gas mixture and (0001) c-plane monocrystalline aluminium nitride (AlN) films at high temperatures, in the 800-1200 degrees C range. As a typical result, the growth of epitaxial 70 nm thick layers of (111)-fcc Ti1-xAlxN (0.05 = x = 0.65) has been processed. Multicomponent mass transport and diffusion modelling is proposed to assess the experimental results. A good agreement is found between the experimental thickness of the transformed zones and the calculated titanium diffusion length in AlN. Fcc-Ti1-xAlxN phase formation can be regarded as a diffusion-controlled mechanism. The novel experimental methodology developed in this work could help in understanding the complex formation and stability of this technologically important material.