Amorphization, recrystallization and end of range defects in germanium

The controlled doping of germanium by ion implantation is a process which requires basic research before optimization For this reason. we have experimentally studied by transmission electron microscopy both the kinetics of amorphization and of recrystallization of Ge during ion implantation (Ge, P and B) and further annealing As in Si, the crystalline to amorphous phase transition occurs through the linear accumulation of damage with the dose until a certain threshold is reached above which the material turns amorphous We show that the Critical Damage Energy Density (CDED) model can be used in germanium to predict the existence. position and extension of amorphous layers resulting from the implantation of lolls for almost all mass/energy/dose combinations reported here and in the literature During annealing, these amorphous layers recrystallize by solid-phase epitaxy following an Arrhenius-type law which we have determined We observe that this regrowth results in the formation of extended defects of interstitial type Dunng annealing these defects evolve in size and density following all Ostwald ripening mechanism which becomes non-conservative (defects "evaporate") as the temperature is increased to 600 degrees C These results have important implications for the modeling of diffusion of implanted dopant in Ge Transient diffusion may also exist ill Ge, driven by an interstitial component usually not evidenced tinder equilibrium conditions (C) 2009 Elsevier B V All rights reserved.