Reactive chemical vapor deposition of heteroepitaxial Ti1−xAlxN films

Abstract

Processing of Ti_1−xAl_xN thin films by the reactive chemical vapor deposition (R-CVD) technique has been performed from the reaction between a titanium tetrachloride (TiCl₄–H₂) gas mixture and (0001) c-plane monocrystalline aluminium nitride (AlN) films at high temperatures, in the 800–1200 °C range. As a typical result, the growth of epitaxial 70 nm thick layers of (111)-fcc Ti_1−xAl_xN (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-Ti_1−xAl_xN 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.