The measurement of strain in films, grown using pendeo-epitaxy, indicated that the overgrowth (wing) material was crystallographically relaxed. An increase of some 0.02% in the c-axis lattice parameter of the wing material was measured using high-resolution X-ray diffraction. Additional evidence for the increase was provided by an upward shift of the E2 Raman line frequency. Atomic force microscopy revealed a reduction in the density of mixed-type dislocations in the wing. A reduction in screw-type dislocations in the wings, with respect to the stripes, was reflected by a reduction in the high-resolution X-ray diffraction rocking curve full-width at half-maximum of the (00•2) reflections, from 646 to 354arcsec. The off-axis full-width at half-maximum of the wing area was 126arcsec, as compared with 296arcsec for the stripe; thus indicating a reduction in edge-type dislocations as well. The pendeo-epitaxial growth of wings off the (11•0) surface of a GaN stripe produced material that was crystallographically relaxed, contained fewer defects (compared to the stripe) and was atomically smooth on the (11•0) surface.

Strain and Dislocation Reduction in Maskless Pendeo-Epitaxy GaN Thin Films. A.M.Roskowski, P.Q.Miraglia, E.A.Preble, S.Einfeldt, T.Stiles, R.F.Davis, J.Schuck, R.Grober, U.Schwarz: Physica Status Solidi A, 2001, 188[2], 729-32