PRE-AMORPHIZATION DAMAGE STUDY IN AS-IMPLANTED SILICON

The pre-amorphization damage structure in high-energy ion-implanted Si was studied to better understand the processes that eventually lead t o the formation of a continuos amorphous layer. Different kinds of def ect structures would induce different deformation in the host lattice. In this paper we report the results of a systematic study on the depe ndence of the strain profile on the local defect density in nitrogen i mplanted silicon [100] crystals. The study was carried out as a functi on of the ion fluence for three different implantation conditions: ran dom incidence, [100] and [110] channelling. The results of some prelim inary low-temperature (up to 300 degrees C) annealing experiments are also reported. The linear dependence of the strain upon the defect con centration is confirmed by the present results. The extremely low valu e of the proportionality factor is discussed in terms of possible form ation of amorphous clusters even at ion doses well below the amorphiza tion threshold.