The role of substrate steps in the introduction of transformations of interfacial structure and inversion domain boundaries was studied for the GaN/AlN/Si (00▪1)/(111) epitaxial system using topological analysis and high resolution transmission electron microscopy. This epitaxial system could exhibit distinct interfacial structures at the AlN/Si interface, and transformations from one to the other could be introduced by the steps on the substrate surface. The interfacial steps could exhibit dislocation character and they may accommodate the coexistence of energetically degenerate as well as distinct interfacial structures. A substrate step was identified as a potential cause for pinhole formation. Inversion domain boundaries accommodate interfacial transformations when they emanate from the epitaxial interface and could reduce the coherency dislocation character of interfacial steps.

Interfacial Steps, Dislocations and Inversion Domain Boundaries in the GaN/AlN/Si (0001)/(111) Epitaxial System. G.P.Dimitrakopulos, A.M.Sanchez, P.Komninou, T.Kehagias, T.Karakostas, G.Nouet, P.Ruterana: Physica Status Solidi B, 2005, 242[8], 1617-27