Radiation damage–He interaction in He implanted Si during bubble formation and their evolution in voids

He atoms were implanted in crystalline and pre-amorphized silicon wafers at doses in the 2×10 16 1×10 17 cm −2 range. Using transmission electron microscopy (TEM) we monitored the evolution of He bubbles into voids upon thermal annealing. Bubbles are formed in both crystalline and amorphous silicon. However, in amorphous material bubble interaction with the moving crystalline–amorphous interface during the epitaxial regrowth prevents their evolution into voids. By implanting He at different target temperatures in crystalline Si, thus by changing the structure of radiation damage, we found that the interaction between point defects and He atoms is essential for the generation of He bubbles and for their subsequent evolution into voids.