Kinetics of MnAs growth on GaAs(001) and interface structure

On different As-rich GaAs(001) templates, well characterized by reflectance difference spectroscopy, nucleation and growth of NiAs-type MnAs is invest igated in real time by reflection high-energy electron diffraction. Using v ery high As-4/Mn flux ratios and low growth rates, one of the two occurring azimuthal alignments of the ((1) over bar 100) orientation can be nearly s uppressed even in the nucleation stage, and it vanishes completely with fur ther growth. Annealing is found to be very effective in surface smoothing. In dependence on the As/Mn ratio the MnAs((1) over bar 100) surface develop s different reconstructions. This finding is important for further investig ations in the growth of double heterostructures. High-resolution transmissi on electron microscopy of as-grown MnAs/GaAs samples reveals an abrupt inte rface. The lattice mismatch accommodation is anisotropic with regularly arr anged misfit dislocations along the [(1) over bar 10] direction and less lo calized coherency strain in the [110] direction, consistent with a near-coi ncidence-site lattice model. (C) 1999 American Vacuum Society. [S0734-211X( 99)02904-2].