The effects of the annealing temperature on the formation of helium-filled structures in silicon

He(+) ions were implanted into (100) Si at energies from 30 to 120 keV and fluences from 5x10(15) to 1x10(16) cm(-2). After implantation, pieces of these samples were subjected to thermal annealing at temperatures ranging from 300 degrees C to 1000 degrees C for times from 30 to 6600 s. The microstructure evolution of He induced cavities were investigated by Transmission Electron Microscopy (TEM). Plate-like He filled structures are observed in samples annealed at low temperatures. The plate-like structures present distinct morphological developments depending on the annealing temperature. These results are discussed assuming that the structures contain a high He to vacancy ratio, which leads to the formation of highly pressurized He bubbles instead of cavities devoid of gas. (C) 1999 Elsevier Science B.V. All rights reserved.