Atomic structure of AlN/Al2O3 interfaces fabricated by pulsed-laser deposition

The atomic structure of AlN/Al2O3 interface fabricated by pulsed laser deposition was characterised by HRTEM combined with systematic multi-slice HRTEM image simulations. It was found that the AlN film deposited on a (0001) Al2O3 substrate grows epitaxially with the orientation relationship of (0001)AlN//(0001)Al2O3 and [bar1100]AlN //[11bar20]Al2O3, with an atomically sharp interface. The observed interface showed best correspondence with the rigid structural model that AlN is terminated by Al at the interface, while the Al2O3 substrate is terminated by O. Detailed structural analysis indicates that Al sites at the interface are coordinated by both oxygen and nitrogen in this model, with similar coordination environment in AlN. This favoured coordination state at the interface may stabilise the AlN/Al2O3 interface. 20 refs.