Van der Pauw measurements, C‐V measurements and secondary ion mass spectrometry were used to study the rapid diffusion of Be in heavily doped GaAs epilayers grown by MBE. The concentration dependence of Be diffusion was measured and a discrepancy was found to exist, at high doping levels, between these experimental results and a previously proposed Be interstitial‐substitutional diffusion model. The threshold for fast Be diffusion versus doping concentration was determined, and a diffusion coefficient as high as 2 x 10−12cm2/s was observed at 600C. A surface Fermi‐level pinning effect model was proposed, in addition to the interstitial‐substitutional model, which successfully explained the onset of fast Be diffusion in MBE‐grown GaAs at high dopant levels.

Surface Effect‐Induced Fast Be Diffusion in Heavily Doped GaAs Grown by Molecular‐Beam Epitaxy. Y.C.Pao, T.Hierl, T.Cooper: Journal of Applied Physics, 1986, 60, 201