Characterization of Al₂O₃ Thin Films on GaAs Substrate Grown by Atomic Layer Deposition

Al₂O₃ thin films are grown by atomic layer deposition on GaAs substrates at 300°C. The structural properties of the Al₂O₃ thin film and the Al₂O₃/GaAs interface are characterized using x-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and x-ray photoelectron spectroscopy (XPS). The XRD results show that the as-deposited Al₂O₃ film is amorphous. For 30 atomic layer deposition growth cycles, the thicknesses of the Al₂O₃ thin film and the interface layer from the HRTEM are 3.3nm and 0.5nm, respectively. XPS analyses reveal that the Al₂O₃/GaAs interface is almost free from As₂O₃.