Improvement of Crystalline Quality in GaAs Layer Grown on Thermal Cyclic Annealed SOS
Kaoru KADOIWA, Hajime SASAKI, Yoshikazu TERAI and Yasufumi FUJIWARA
Abstract:High quality GaAs layer grown on silicon-on-sapphire (SOS) have been successfully achieved by thermal cyclic annealing (TCA) procedure using the two reactor MOCVD system after Si film deposition. The quality of silicon film measured by X-ray diffraction showed 50% narrowing of full width at half maximum intensity (FWHM) after TCA process. A spherical sapphire substrate was used to investigate substrate Offset angle dependence on crystalline quality of the GaAs layer. By applying TCA for SOS substrate before GaAs layer growth, extra smooth surface whose roughness of less than }30nm could obtained within a wide area of spherical SOS surface. At the smooth region, clear Franz-Keldysh oscillations (FKOs) were observed by photoreflectance (PR) spectroscopy. It also indicated that the cystalline quality of GaAs layer grown on TCA treated SOS was extremly high. Key Words:GaAs, Silicon-on-sapphire (SOS), MOCVD, Thermal cyclic annealing (TCA), Photoreflectance (PR)