Evolution of the surface morphology of Fe grown on GaAs (100), (311)A, and(331)A substrates by molecular beam epitaxy

We study the growth of Fe by molecular beam epitaxy on GaAs (100), (311)A, and (331)A substrates in dependence on the termination (reconstruction) of the GaAs surface and Fe growth temperature. Crystal quality and surface mor phology of the 20- and 160-nm-thick Fe layers are characterized by double-c rystal x-ray diffraction and atomic force microscopy. On GaAs (100) substra tes we obtain very smooth Fe layers for As-rich surface reconstructions at a growth temperature of 50 degreesC. Less As-rich surface reconstructions p roduce macroscopic defects whose density increases on more Ga-rich surface reconstructions. On GaAs (311)A and (331)A substrates smooth layers with go od crystal quality are obtained at 0 degreesC. The high density of macrosco pic defects in these Fe layers is again eliminated on As-saturated surfaces . The evolution of the Fe surface morphology on the micron-length scale and the successful elimination of macroscopic defects on As-saturated GaAs sub strates is highly relevant for application of these layers, in particular, their integration with the unique lateral semiconductor nanostructures form ed on high-index GaAs (311)A and (331)A substrates. (C) 2001 American Insti tute of Physics.