SURFACE-DIFFUSION LENGTH DURING MBE AND MOMBE MEASURED FROM DISTRIBUTION OF GROWTH-RATES

The growth rates of the layers, which were grown both by usual solid-source molecular beam epitaxy (MBE) and by metalorganic molecular beam epitaxy (MOMBE) using trimethylgallium (TMGa) and metal As as source materials, on a mesa-etched (001) GaAs surface, were measured by in-situ scanning microprobe reflection high-energy electron diffraction (mu-RHEED) from the period of the RHEED intensity oscillation in real time. The diffusion length of the surface adatoms was determined by the gradient of the variation of the growth rate. The obtained values of the diffusion lengths were of the order of a micrometer under the usual growth conditions both in MBE and in MOMBE. The diffusion length in the case of MOMBE was larger than that of a Ga atom in the case of MBE.