Influence of sputtering atmosphere on crystallinity and crystal orientation of AlN thin films deposited on polycrystalline MoSi2 substrates

Highly oriented AlN thin films have been deposited on polycrystalline MoSi2 substrates by r.f. magnetron sputtering. The total sputtering pressure and the nitrogen concentration in the sputtering gas had a significant influen ce on the crystallinity and crystal orientation of the films. The film depo sited at a sputtering pressure of 0.6 Pa and a nitrogen concentration of 20 % indicated high crystallinity, high c-axis orientation (sigma = 3.1 degree s) and very low surface roughness (R-a = 0.7 nm). The crystallinity, crysta l orientation, composition and morphology of the films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, and atomic farce micr oscopy. The nitrogen concentration hardly had an effect on the composition of the films; however, it had a great influence on the shape of the fine gr ains constituting the films. The shape of the grains drastically changed fr om triangular pyramids of various sizes to uniform fine grains with increas ing nitrogen concentration. (C) 1998 Chapman & Hall.