Effects of Substrate Temperature and Nitrogen Pressure on Growth of AlN Films by Pulsed Laser Deposition

Highly oriented aluminium nitride (AlN) films are grown on p-Si (100) substrates by pulsed laser deposition, and their characteristics of structure and composition are studied by x-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. The results show that the deposited films exhibit good crystalline properties with a sharp x-ray diffraction peak at 2θ = 33.15° corresponding to AlN h⟨100⟩ crystalline orientation. The influences of substrate temperature and ambient nitrogen (N₂) pressure on the crystallinity of AlN films are remarkable. At room temperature, when the ambient N₂ pressure arises from 5×10⁻⁶ Pa to 5 Pa, the crystallinity of the film becomes better. When the substrate temperature is 600°C, the film has the best crystallinity at 0.05 Pa. Furthermore, the effects of substrate temperature and ambient N₂ pressure on the combination of Al-N bonds and surface morphology of AlN films are also studied.