Characterization of GaAs thin films grown by molecular beam epitaxy on Si-on-insulator

Abstract

The direct growth of GaAs by molecular-beam epitaxy (MBE) on silicon-on-insulator (SOI) structure is presented. Rutherford backscattering and channeling (RBS/C), transmission electron microscope (TEM), and infrared (IR) reflection measurements have been employed to characterize the GaAs thin films. RBS/C results show that there is considerable lattice disorder at the GaAs-Si interface, but the crystal quality of the GaAs thin films improves remarkably toward GaAs surface for thicker films where the minimum channeling yield drops to 10% IR reflection spectra in the wavenumber range 1500 - 5000 cm-1 were measured for GaAs thin films on SOI. Interference fringes observed in IR reflection spectra also prove that the crystalline GaAs thin films have been deposited on SOI substrates. By computer simulation of the IR reflection interference spectra refractive index profiles of the GaAs/SOI structures were obtained.