Chemical composition of InxGa1-xAs epilayers grown simultaneously on differently oriented GaAs substrates

We investigate the In-composition of InxGa1-xAs ternary layers epitaxially grown by molecular beam epitaxy. The epilayers of different indium content (mole fraction 0.2<x<1) are grown simultaneously onto GaAs substrates of di fferent crystallographic orientation, namely (0 0 1). (1 1 1)B and (1 1 3)A surfaces. High-resolution X-ray diffraction, electron probe microanalysis, energy-dispersive X-ray spectroscopy and scanning electron microscopy meas urements show that for a suitable set of parameters high-quality InxGa1-xAs layers can be simultaneously grown by MBE on differently oriented GaAs sub strates. Secondary ion mass spectrometry measurements show that the In-inco rporation is constant over the whole layer thickness and for all surface or ientations. In addition, the epilayers grown during the same run have the s ame chemical composition independent from the substrate surface orientation . Moreover. a comparison of the InAs mole fractions obtained by X-ray diffr action and electron probe microanalysis confirms the validity of Vegard's r ule for the InxGa1-xAs lattice parameter and the Poisson's ratio within 0.5 % of the experimental accuracy. (C) 2001 Elsevier Science B.V. All rights r eserved.