INVESTIGATION OF STRAIN EFFECTS IN SELECTIVELY GROWN GAAS ON SI

In this paper we describe the investigation of strain effects in GaAs layers which were selectively grown on Si substrates by metalorganic vapor phase epitaxy (MOVPE). The experimental strain determined by high resolution X-ray diffraction, Raman and photoluminescence measurements were compared to an analytical thermal strain model and showed very good agreement. The strain relaxation observed in selectively grown GaAs layers depends on the square dimensions and the layer thickness of the GaAs squares. BY cathodoluminescence measurements, an inhomogeneous strain distribution inside the GaAs layers as predicted by our thermal strain model could be verified. Differences in the experimentally and theoretically evaluated thermal strain are explained by the dislocation movement during the high pressure part of the cooling process after growth.