A study was made of the diffusion-induced broadening of a nitrogen doping region embedded in a GaAs layer that was grown by molecular beam epitaxy onto a GaAs substrate. The markedly non-Gaussian shape of the N distribution measured by secondary ion mass spectroscopy after isothermal annealing at between 724 and 922C could be well described within the framework of a kick-out mechanism. This yielded not only nitrogen-related diffusivities based upon the mobility of Ni but also As sublattice-related self-diffusivities. The As data were represented by:

D(cm2/s) = 0.25 exp[-3.88(eV)/kT]

and agreed with directly measured As tracer diffusion coefficients. The present results provided evidence that self-interstitials were more important for atomic transport processes on the As sub-lattice than were vacancies.

N.A.Stolwijk, G.Bösker, J.V.Thordson, U.Södervall, T.G.Andersson, C.Jäger, W.Jäger: Physica B, 1999, 273-274, 685-8