The influence of misfit dislocations on the surface morphology and transport properties of In0.52Al0.48As/In0.75Ga0.25As/InP pHEMT structures was demonstrate grown by molecular beam epitaxy with InGaAs channel thicknesses that range from 20–35 nm. The differences in carrier scattering along different crystallographic directions for a given sample as determined by magnetotransport Hall bar measurements correspond to the asymmetric distribution of the orthogonal 60° misfit dislocations. The misfit dislocations introduce a well-defined roughness spectrum through the introduction of surface and interface steps and this roughness could be modeled in a straightforward fashion. This highly directional interface roughness was considered to be the scattering mechanism that was responsible for differences in mobility that were observed from sample to sample along different crystallographic directions. It was suggested that these results had implications for structures in the initial stages of strain relaxation and for metamorphic-based structures.

Interfacial Roughness and Carrier Scattering due to Misfit Dislocations in In0.52Al0.48As/In0.75Ga0.25As/InP Structures. M.Naidenkova, M.S.Goorsky, R.Sandhu, R.Hsing, M.Wojtowicz, T.P.Chin, T.R.Block, D.C.Streit: Journal of Vacuum Science and Technology B, 2002, 20[3], 1205-8