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A silicon process simulator SUPREM-IV was used to model uphill diffusion on implanted magneisum in gallium arsenic during a 900 degree centigrade anneal. The diffusion occurs through the substitution-interstitial-diffusion process. The implantation process produces the abnormal diffusion behavior using excess interstitials and vacancies obtained from Boltzmann transport equation calculations.

The diffusion of ion-implanted Be in GaAs is studied by comparing the diffusion of implanted Be in undoped GaAs and in GaAs uniformly doped with Zn or Si. The Si-doped sample exhibits much less Be diffusion compared to the undoped case, while the Zn-doped sample shows much more Be diffusion. The diffusion in the doped substrate cases can be simulated with a constant Be diffusivity, as opposed to a concentration-dependent diffusivity in the undoped case. The results are consistent with the substitutional-interstitial diffusion mechanism, which predicts a diffusivity that is dependent on the net hole concentration. [ABSTRACT FROM AUTHOR]

The diffusion of implanted Be in GaAs was studied by annealing samples of GaAs implanted with low and high doses of Be. The high-dose (1×1014 cm-2) samples show an increase in diffusion with increasing anneal temperature from 700 to 900 °C. However, the low-dose (2×1013 cm-2) samples show a decrease in diffusion as the temperature is increased. The temperature dependence of the low-dose case can be reversed by coimplantation of 1×1014 cm-2 boron. This behavior is explained in terms of the substitutional-interstitial diffusion mechanism and the relative concentrations of Be interstitials and Be substitutionals for the different cases. [ABSTRACT FROM AUTHOR]

Examines the interaction of implantation-induced dislocation loops in crystals and interstitials in silicon. Experiments under dry oxidation conditions; Consideration of the interaction as a diffusion limited process; Agreement of simulations with secondary ion mass spectroscopy.