Modeling GaN growth by plasma assisted MBE in the presence of low Mg flux

Nathan Sipe, University of Nevada, Las Vegas
Rama Venkat, University of Nevada Las Vegas, Department of Electrical & Computer Engineering

Materials Research Society Internet Journal of Nitride Semiconductor Research: Volume 7, Article 1

Description

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) Galimited 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.