Removal of vacancy type clusters by low energy ion generated self-interstitials in crystalline silicon

In the present study high dose 50 eV Ne and Kr ion implantation were used t o remove nanosize cavities in (100) monocrystalline silicon. Nanosize cavit ies were created by 30 keV He-3 implantation with a dose of 5 x 10(16) cm(- 2) and subsequent annealing in vacuum at 1100 K. Only in the case of Ne irr adiation the cavities were filled up with self-interstitials generated at t he surface by Ne ions. The implantation temperature was kept at about 600 K to avoid formation of irradiation defects in the near surface region. The Ne implantation dose varied from 10(18) to 3 x 10(19) cm(-2) The size and t he location of the clusters before and after Ne implantation were determine d by the variable energy positron annihilation (VEP) technique. The evoluti on of the helium-vacancy clusters during all the experimental treatments of the samples, including 30 keV helium implantation, 1000 K annealing and Ne implantation, was simulated using the Monte-Carlo program MODEX, Reasonabl e agreement was obtained between the simulated and experimentally observed results, suggesting that the physical model used in the simulation is corre ct. (C) 1999 Elsevier Science B.V. All rights reserved.