Search for content and authors
 

Comparative analysis of (0001)GaN and (001)GaAs growth kinetics

Vladimir Mansurov 1Yurii G. Galitsyn Konstantin S. Zhuravlev 

1. Institute of semiconductor physics (ISP), Lavrentiev, Novosibirsk, Russian Federation

Abstract

It is well known that the bimolecular reaction of dissociation of As4 molecules on the surface (As4+As4 => 2As2+As4gas) 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=>N2gas+2H2gas. 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.
VGaN=VmaxGaN×f(λ), VGaAs=VmaxGaAs×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
  • Legal notice:
 

Related papers

Presentation: poster at E-MRS Fall Meeting 2003, Symposium C, by Vladimir Mansurov
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-05-07 07:25
Revised:   2009-06-08 12:55