GISAXS studies of structural modifications in ion-beam amorphized Ge

Grazing incidence small angle scattering of X-rays (GISAXS) was used to analyze structural modifications in implantation-damaged Ge. Samples were implanted by different doses of 74Ge, from 3 x 1012 cm-2 to 3 x 1016 cm-2; at room- or liquid nitrogen-temperature, respectively. We have found that the micro-structure in amorphous Ge, continuously and consistently evolves as a function of ion dose but differs according to the implantation temperature. In RT-samples small vacancy nanoclusters agglomerate in the end-of-range region of implanted layer even before complete amorphization. With higher doses nanoclusters increase and coalesce into nano-voids. For the highest dose, the onset of porosity is confirmed. On the other hand, in LN-implanted samples, the clustering-related signal is much weaker and evolves more slowly