Homoepitaxial growth kinetics in the presence of a Schwoebel barrier

Nowadays it is well-recognized that the additional barrier to downhill adat om diffusion at the step edge plays an important role in the epitaxial grow th. Very recently we have developed a simple model for homoepitaxial layer growth kinetics which allows to take into account the Schwoebel barrier imp act on adatoms interlayer diffusion by using the concept of a feeding zone, as we have proposed earlier. This paper is devoted to further refinement a nd extension of the model to the cases of an arbitrary nucleus size and coa lescence behaviour of growing islands. The model consists of an infinite se t of coupled non-linear rate equations for adatom and 2D island surface den sities and coverage in each successive growing layer. These equations in co mbination with an integral condition determining the new layer formation on set fully describe homoepitaxial growth kinetics at predetermined five mode l parameters, characterizing adatoms diffusion rate, critical nucleus size and stability, Schwoebel barrier effect, and coalescence. The growth mechan isms and kinetics in a wide range of parameter values are studied and growt h mechanism phase diagrams in various parameter spaces are constructed and discussed. (C) 2000 Elsevier Science B.V. All rights reserved.