The reported anomalous so-called up-hill diffusion behavior of implanted Si in this material was simulated. The up-hill diffusion had been found to be implantation-dose dependent. No up-hill diffusion was observed below a threshold dose of 3 x 1014/cm2. It was suggested here that the anomalous behavior was due to the formation of vacancy clusters when the implantation dose was sufficiently high. Atoms of Si were assumed to migrate through the Ga vacancies, which were comparatively mobile. On the other hand, the immobile clusters collected Si atoms around the vacancy peak; thus resulting in up-hill diffusion. A dip in the carrier concentration profile also occurred at high implantation doses. The occurrence of this dip was attributed to the effect of the trapping of Si atoms into clusters where the former were not electrically activated.

V.C.Lo, J.Z.Sun: Modelling and Simulation in Materials Science and Engineering, 1996, 4[6], 613-21