Characterization of InGaAs/ALGaAs/GaAs heteroepitaxial structures by transmission electron microscopy and energy dispersive spectroscopy

Abstract The primary transmission electron microscopy (TEM) imaging methods which are currently used to analyse III–V compound semiconductor heterostructures are discussed. InGaAs/AlGaAs/GaAs heteroepitaxial layers grown by molecular beam epitaxy were studied by cross-sectional TEM and energy dispersive spectroscopy (EDS). The presence of interfacial roughness, fine periodic striation contrast due to Al composition oscillations, layer contrast in the lattice images, and defects observed by TEM in selected samples are discussed. EDS on TEM was of limited utility in determining the composition of thin epitaxial layers and comparing the composition near and away from a defect.