Helium and hydrogendashdecorated cavities in silicon

The formation of stable voids in Si by helium implantation and annealing is studied with the aid of the slow-positron depth profiling method. Decoration of the voids with helium or hydrogen reduces positronium formation in the voids and thus lowers the high value of the S-parameter found for large empty cavities in Si. Annealing at 800°C recovers the original empty cavities.