J. Phys. III France
Volume 7, Numéro 12, December 1997
Page(s) 2317 - 2324
DOI: 10.1051/jp3:1997261
J. Phys. III France 7 (1997) 2317-2324

Microstructure of Pyramidal Defects in InSb Layers Grown by Atomic Layer Molecular Beam Epitaxy on InP Substrates

J.C. Ferrer1, 2, F. Peiró1, A. Cornet1, J.R. Morante1, T. Utzmeier3 and F. Briones3

1  EME, Dept. Física Aplicada i Electrònica, Universitat de Barcelona, Av. Diagonal, 645-647, 08028, Barcelona, Spain
2  Serveis Científico-Tècnics, Universitat de Barcelona, Lluís Solé i Sabarís, 1-3, 08028, Barcelona, Spain
3  Instituto de Microelectrónica de Madrid (CSIC), Isaac Newton, 8, Parque Tecnológico de Madrid, 28760, Tres Cantos, Madrid, Spain

(Received 3 October 1996, revised 22 April 1997, accepted 25 August 1997)

We report on the structural characterization of epitaxial InSb films grown on InP substrates by atomic layer molecular beam epitaxy at relatively low temperatures (330 $^{\circ}{\rm C} < T < 400$ $^{\circ}$C). Moreover, we study the effect of the introduction of an intermediate InSb/InP buffer layer grown by molecular beam epitaxy. The studies were carried out by TEM and HRTEM, to investigate the densities and nature of the defects and the accommodation mechanism between the two types of layers which have a large lattice mismatch (10.4%). Results show a high defect density at the interface vicinity whatever the growth method employed, with or without buffer layers, but better quality layers are obtained as growth proceeds. The prevailing type of defects are threading dislocations and stacking faults for both types of samples, but the introduction of the intermediate layers leads to the formation of two types of complex three-dimensional defects, consisting in crystal misorientations, that induce an anomalous growth of the InSb layer leading to different growth rates and the formation of pyramidal or truncated pyramidal hillocks on the surface. In this case scanning electron microscopy and Raman analysis were also performed to study the influence of the defects on surface morphology and confirm their structure. Moreover, anisotropy of the stacking fault distribution is noticed in this sample: the density for [ $\bar{110}$] -(111)A slip planes is higher than for the [110]-(111)B slip planes. Strain due to large lattice mismatch is relieved in both types of samples by the generation of a pure edge-type misfit dislocation array.

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