Aluminium nitride (AIN) films have been synthesized on Si(l00) substrates by ion-beam-enhanced deposition. The spreading resistance profile results suggest that the spreading resistance decreases with increasing rates of Al evaporation. If the evaporation rate of Al is higher than 2.5 A/s, the quality of the AIN film will greatly deteriorate. The spreading resistance of the best quality film deposited at 0.5 A/s rate of Al was larger than 108Ω. X-ray photoelectron spectroscopy measurements indicate the formation of AIN films at 0.5 and 1.0 A/s evaporation rates of Al. With the increasing evaporation rate of Al, the ratio of N to Al is decreased. When deposited at 0.5 and 1.0A/s evaporation rates of Al, the ratios of N to Al were 0.402:1 and 0.250:1, respectively. Atomic force microscopy observation also shows that the surfa:e of the AIN film formed at the 0.5 A/s rate is smoother and more uniform than that formed at 1.0 A/s.