Gallium- and arsenic-induced oscillations of intensity of reflection high-energy electron diffraction in the growth of (001) GaAs by chemical beam epitaxy

Abstract

The observations of a damped intensity oscillation using reflection high-energy electron diffraction during the growth of GaAs by chemical beam epitaxy using triethylgallium and arsine are reported. It is experimentally demonstrated that the As flux can be instantly shut off without any memory effect by measuring the Ga-induced intensity variation and the subsequent As-induced oscillations. The Ga deposition, free of any background As contamination, makes possible the direct determination of metal-alkyl adsorption and pyrolysis efficiency on the hot substrate surface. At 530 °C a (4×6) diffraction pattern is observed when Ga is deposited alone. The appearance of this (4×6) reconstruction along with the associated intensity behavior indicates that the first monolayer of Ga grows two-dimensionally. This can be understood qualitatively in terms of the simple kinematic model involving only surface roughness. These observations support a two-dimensional growth mechanism in the growth process. Furthermore, the ability to control submonolayer deposition of pure Ga coupled with the in situ electron-diffraction monitoring technique presents a new growth configuration of atomic layer epitaxy to be realized by chemical beam epitaxy.