REFLECTION HIGH-ENERGY ELECTRON-DIFFRACTION INTENSITY OSCILLATION STUDY OF THE GROWTH OF GAAS ON GAAS(111)A

Reflection high energy electron diffraction (RHEED) intensity oscillations have been studied over a wide range of growth temperatures (300-60-degrees-C) and As: Ga flux ratios (2:1-15:1), during the growth of GaAs on singular GaAs(111)A substrates by molecular beam epitaxy (MBE). The oscillation period is strongly dependent on both growth temperature and the As: Ga flux ratio, in contrast to observations on GaAs(001). A growth rate equivalent to that expected from the supply of Ga is only measured (by RHEED) at high As: Ga ratios and/or low growth temperatures. This behaviour can be explained through a model in which arsenic has a low initial sticking coefficient. thus allowing the formation of free Ga at the beginning of growth, alongside two-dimensional (2D) GaAs island growth. Activation energies related to desorption and surface diffusion of the incident As4 have been obtained.