Epitaxial growth of cubic AlN thin films on (100) and (111) silicon substrates by pulsed laser ablation is reported. The epitaxial AlN films can be grown at temperatures above 630 °C in 100–300 mTorr of N2. The epitaxial orientation relationships are (100)AlN//(100)Si and [010]AlN//[010]Si, and (111)AlN//(111)Si and [011¯]AlN//[011¯]Si. The growth of microtwins on (111) planes of AlN was also observed. In the present study, for the AlN thin films grown on (100)Si at around 680 °C in 100 mTorr of N2, the epitaxial growth can cover about 90% of the film region. ©1995 American Institute of Physics.