Monitoring interstitial fluxes by self-assembled nanovoids in ion-implanted Si/SiGe/Si strained structures

We report on the effect of the rapid thermal annealing (RTA) ambiance on evolution of self-assembled voids of nanometer size. The spherically shaped voids are produced in molecular beam epitaxially grown Si/SiGe/Si strained structures with in-situ implantation of 1 keV Ge ions followed by RTA at 800 or 900 deg. C. The voids are of nanometer size and are exclusively assembled in the narrow SiGe layer. During the RTA, the voids grow in size in a nitrogen ambiance and shrink in an oxygen ambiance. The evolution of the voids correlates well with oxidation-induced injection of excess interstitials. Prospects for point defect monitoring are discussed