The interdiffusion of lattice-matched InP/(In,Ga)As superlattice structures (nominally undoped, p-doped and n-doped) was studied. The point-spread function of an electron beam was used to correct the experimental data (obtained as 50nm x 50nm X-ray maps) in order to obtain the diffusion profiles of group-V elements (As, P) after annealing. The results, which revealed a marked asymmetry of the As profiles after annealing, were interpreted by using a model which was based upon coherent diffusion of the group-III and group-V elements on their own sub-lattices; each of which was treated as a regular solution. A mathematical procedure which was based upon minimization of the difference between measured and predicted concentration profiles was used to deduce the 2 lattice-specific composition-dependent velocities from the experimental diffusion profiles. Good agreement was found between the experimental measurements and the predictions of the model.

Experimental Investigation and Modelling of Diffusion in the InP/(In,Ga)As Heterostructures. J.Bursik, D.V.Malakhov, Y.Wang, G.C.Weatherly, G.R.Purdy: Journal of Applied Physics, 2002, 91[12], 9613-21