Molybdenum films were deposited on Al2O3(0001) substrate by ion-beam assisted deposition (IBAD). The microstructure of the films and the interface between molybdenum films and Al2O3 (0001 ) have been studied on atomic scale by using the cross-sectional technique and HREM. The results show that molybdenum films deposited by IBAD result in a columnar microstructure with columns which are uniform in width from substrate to the top of the films. The average column diameter is about 8 nm. No voids were found in ...