The temporal behaviour of reflection-high-energy-electron-diffraction intensity and implications for growth kinetics during molecular beam epitaxial growth of GaAs/Al xGa 1− xAs(100) modulated structures

Abstract

Abstract We present some results of a systematic examination of the reflection-high-energy-electron-diffraction (RHEED) intensity behaviour of static GaAs(100) surfaces, and during molecular beam epitaxial (MBE) growth of GaAs and AlAs on such surfaces. The growth condition dependent role of surface kinetic processes in controlling the nature of the surfaces and interfaces is emphasized which, amongst other things, shows the need for two different optimum arsenic pressures for the growth of good normal and inverted interfaces in modulated structures, under most growth conditions. For the customary practise of forming interfaces during continuous growth of alternate layers, an example of special growth condition requiring only one optimum arsenic pressure is presented. The significance of the individual layer thicknesses and the total thickness of the modulated structure in controlling the quality of normal and inverted interfaces formed at the chosen growth conditions is revealed through a comparison of the RHEED dynamics during growth of (GaAs) 2 /(AlAs) 2 and (GaAs) 6 /(AlAs) 6 superlattices.