Effects of the Two-Step Growth Method for GaAs Grown on CaF2/Si(111) with the Electron Beam Surface Modification Technique

Abstract

Effects of the two-step growth method were investigated in epitaxial growth of the GaAs layer on the CaF2/Si(111) substrate, where the CaF2 surface was modified by the electron beam exposure technique. In-situ optical observation of the initial stage of GaAs growth revealed that sticking coefficient of GaAs on the CaF2 was low and GaAs grew with a three-dimensional growth mode at 550°C or higher, while the sticking coefficient was increased and GaAs grew with a two-dimensional mode at 500°C or lower. The GaAs layer with good surface morphology without a twin boundary was obtained by the two-step growth method in which the initial layer was grown at less than 500°C and the succeeding layer was grown at 600°C. X-ray full-width at half maximum (FWHM) of 400 arcsec and Hall mobility of electrons more than 2,300 cm2/Vs were obtained in a 1.5-µm-thick GaAs layer grown by the two-step growth method.