Aluminium nitride films prepared by reactive magnetron sputtering

The exceptional properties of aluminium nitride make this material a very promising candidate for a variety of technological applications. In this paper we report our work on the preparation of thin films of aluminium nitride by reactive DC and RF magnetron sputtering. The physical and electrical properties of the films were studied as a function of the preparation conditions: concentration of nitrogen in the reactive gas mixture, the substrate temperature, the plasma power and the horizontal distance from the centre of the target. X-ray diffraction data indicated that highly oriented polycrystalline films could be fabricated. Rutherford backscattering and nuclear reaction analysis showed that nearly stoichiometric films could be prepared using nitrogen concentrations greater than 50%. For the DC plasma process, bombardment of the growing film plays a very significant role. The film growth mechanism was found to be very different for the RF plasma The nuclear analysis of the films prepared at different lateral distances, together with measurements of the substrate potential, permitted modelling of the film formation process for both the DC and RF plasmas.