Surface diffusion lengths of Ga molecules during GaAs MOMBE (metalorganic molecular beam epitaxy) growth

Abstract

Surface diffusion of Ga molecules during the MOMBE (metalorganic molecular beam epitaxy) growth of GaAs using TEGa (triethylgallium) was studied by measuring the RHEED (reflection high energy electron diffraction) intensity oscillations on the (001) GaAs vicinal surface. It is found that the obtained diffusion constant values for the MOMBE growth are the same as those for the solid source MBE growth. It is also found that the damping speed of the RHEED intensity oscillation on the (001) surface depends on the flux ratio of TEGa to Ga when both beams are supplied on the surface. It is concluded that some of the incident TEGa molecules pyrolyze into Ga atoms and migrate on the surface, that the others migrate as Ga alkyl molecules and pyrolyze at the steps or kinks, and that the diffusion lengths of Ga alkyl molecules are longer than those of Ga atoms.