Dislocation Climb in c-Plane AlN Films
Fu, W Y and Kappers, M J and Zhang, Y and Humphreys, C J and Moram, M A
A series of AlN films of increasing thickness (up to 4 µm) were grown on c-plane sapphire by metalorganic vapour phase epitaxy. Plan-view transmission electron microscopy (TEM) images reveal that the dislocation density at the film surface reduces with increasing film thickness, whereas cross-sectional TEM data reveal that dislocation reduction continues to occur beneath the film surface during growth, resulting in the preferential annihilation of c-type and/or (a+c)-type dislocations. We conclude that dislocation movement occurs by climb during AlN growth.
Department of Materials
Imperial College London
Royal School of Mines
London, SW7 2AZ - UK