Transmission electron microscopic studies were made of the defect configurations in hetero-epitaxial structures which had been grown by means of metalorganic vapor phase epitaxy. The GaAs layers were deposited by using conventional 2-step growth methods. Upon introducing a thin AlGaAs layer between the low-temperature and high-temperature GaAs layer, a significant reduction in the dislocation density in the upper GaAs layer was observed after thermal cycle annealing. The effect of thermal cycle annealing, and the role which was played by the AlGaAs inter-layer together with the annealing, in reducing the defect density was explained on the basis of the transmission electron microscopic observations.

N.Y.Jin-Phillipp, F.Phillipp, T.Marschner, W.Stolz, E.O.Göbel: Journal of Crystal Growth, 1996, 158[1-2], 28-36