BEATING IN THE RHEED INTENSITY OSCILLATIONS DURING SURFACTANT-MEDIATED GAAS MOLECULAR-BEAM EPITAXY - PROCESS PHYSICS AND MODELING

In a recent work, beating in the reflection high energy electron diffr action (RHEED) intensity oscillations were observed during molecular b eam epitaxial (MBE) growth of GaAs with Sn as a surfactant. The streng th of beating is found to be dependent on the Sn submonolayer coverage with strong beating observed for 0.4 monolayer coverage, For a fixed temperature and flux ratio (Ga to As), the period of oscillation decre ases with increasing Sn coverage, In this work, we have developed a ra te equation model of growth to investigate this phenomenon. In our mod el, the GaAs covered by the Sn is assumed to grow at a faster rate com pared to the GaAs not covered by Sn. Assuming that the electron beams reflected from the Sn covered surface and the rest of the surface are incoherent, the results of the dependence of the RHEED oscillations on Sn submonolayer coverages for various Sn coverages were obtained and compared with experimental data and the agreement is good.