Thin films of stoichiometric cubic TiN were directly deposited, using room-temperature radio-frequency magnetron sputtering, onto the (00•1) surfaces of GaN epilayers which were grown on c-plane sapphire. Chemical etching and in situ dry etching of the free GaN surface permitted epitaxial growth of the deposited TiN films; as revealed by high-resolution electron microscopic observations. Upon taking account of the experimentally determined orientation relationship between the 2 structures, (00•1)GaN||(111)TiN; [11•0]GaN||[1¯10]TiN, families of dislocations were expected to appear in the interface plane with a spacing of 4.5nm in order to accommodate the 5.8% misfit. The circuit-mapping technique was used to analyse the misfit dislocation content of high-resolution transmission electron microscopic images, as it permitted an exact determination of the Burgers vector. This gave a result of ½[01¯1]TiN or 1/3[1¯2•0]GaN. A demi-step of height cGaN/2 was observed at the TiN/GaN interface. From there, a (11¯2) twin propagated into the TiN layer.

Interfacial Dislocations in TiN/GaN Thin Films. P.Komninou, G.P.Dimitrakopulos, G.Nouet, T.Kehagias, P.Ruterana, T.Karakostas: Journal of Physics - Condensed Matter, 2000, 12[49], 10295-300