It is well known that the bimolecular reaction of dissociation of As₄ molecules on the surface (As₄+As₄ => 2As₂+As₄^gas) plays an important role in the molecular beam epitaxy (MBE) of GaAs using Ga and As₄ fluxes. This reaction provides the formation of As₂ active intermediate complexes. This is the necessary stage in the chain of successive steps of surface reactions for incorporation of the V-group atoms into lattice sites.
On the other hand, the analysis of the growth kinetics of GaN by MBE using Ga and NH3 fluxes under Ga rich conditions reveals the importance of the recombination of NH₂ radicals: NH₂+NH₂=>N₂^gas+2H₂^gas. But in contrast to GaAs in this case the bimolecular reaction decreases the concentration of the active species (NH₂ radicals) on the surface.
We have developed kinetic models for the growth of GaN and GaAs in the frame of the mean field kinetics equations. Analytical expressions for the growth rate were derived. For the correct comparison of the GaN and GaAs growth rates the normalized characteristic functions f(λ) and g(λ) were introduced.
V^GaN=V_max^GaN×f(λ), V^GaAs=V_max^GaAs×g(λ) ,
For both materials the parameter λ depends on the substrate temperature and pressure (of NH₃ or As₄) in a similar way. Namely, it decreases with increasing substrate temperature and increases with increasing NH₃ (As₄) pressure. However, the characteristic functions f(λ) and g(λ) are drastically different: g(λ)->0, f(λ)->1 when λ tends to zero, and vice versa g(λ)->1, f(λ)->0 when λ tends to infinity.
Hence, the growth rate should increase with temperature for GaN (normal kinetics) and decrease for GaAs (anomalous kinetics), which is in good agreement with experimental data.
The authors are grateful to the RFBR financial support (grant 02-03-32307) .

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/541 must be provided.

1. Growth kinetics of (0001)GaN from Ga and NH₃ fluxes