Modeling GaN Growth by Plasma Assisted MBE in the Presence of Low Mg Flux
Nathan Sipe, Rama Venkat
University of Nevada, Las Vegas
This article was received on Wednesday, August 15, 2001 and
accepted on Wednesday, January 16, 2002. Abstract
A
rate equation model is developed to investigate the plasma assisted MBE growth
of GaN in the presence of a fractional monolayer of Mg. Four distinct cases
were identified and modeled - (i) Ga-limited regime (ii) Low N-limited
regime (iii) Medium N-limited regime and (iv) High N-limited regime. In the
model, it is assumed that Ga arriving on a Mg site undergoes faster
incorporation into the epilayer through an exchange reaction compared to Ga
arriving directly on a N surface. Additionally the incorporation rate of Ga
was assumed to depend on the size of the Ga cluster. The results of the model
are in good agreement with that of experiments. The non-monotonic behavior of
growth rate with Ga flux for moderate Mg coverage is explained based on the
incorporation rate dependence of Ga on the cluster size.