Thermal strain in GaAs layers grown by epitaxial lateral overgrowth on Si substrates

Abstract

X-ray diffraction was used to study deformation of GaAs layers grown on Si substrates by liquid phase epitaxial lateral overgrowth (ELO). We show that, in the direction perpendicular to seeding lines, the GaAs ELO stripes bend outwards from the mask due to the tensile strain in the GaAs buffer layer. As narrow as 94 arcsec (004) rocking curves have been measured for the laterally grown parts of ELO stripes what indicates the high quality of ELO GaAs layers grown on GaAs-coated Si substrates. We use our model of strain relaxation via bending of laterally grown parts of ELO layers to explain some recently published results on bending of ELO GaN layers on SiC and sapphire substrates.