Be diffusion during post-growth annealing has been studied in InGaAs epitaxial layers, grown between two undoped InGaAs layers. To explain the observed concentration profiles and related diffusion mechanisms, a general substitutional–interstitial model is proposed. On the one hand, a simultaneous diffusion by dissociative and kick-out models is suggested and, on the other hand, the Fermi-level effect is used to explain the functional dependence change of the effective diffusion coefficient of beryllium species with its concentration. The concentration dependent diffusivity has also been covered to perform an improved data fitting of Be diffusion profiles.

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A comprehensive study of AuMn ohmic contact for p-type GaAs is presented using electrical testing, scanning electron microscopy, Auger electron spectroscopy, and secondary ion-mass spectroscopy. The contact fabrication-Mn proportion against Au, alloying cycle-was optimized taking into account the results of the electrical tests. Contact resistivity values are presented for different doping levels. Unalloyed AuMn contact was found to give a good contact resistivity on samples with an ultrahigh doping level of2 X 1

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