The effect of the annealing ramp rate on the formation of voids in silicon

Abstract

We show the strong dependence on annealing ramp rate of residual open-volume defects insilicon following helium ion implantation and annealing. Helium was implanted at 60 keV energy,1 × 1016 cm−2 fluence into silicon and subsequently annealed to800 °C for 30 min, with ramp rates ranging from 1 to100 °C s−1. The residual defect distribution was probed by means of positron annihilation spectroscopyand ion channeling, with results demonstrating a strong dependence on the ramp rate. Forthese conditions, open-volume defects to which the positron technique is sensitive arepresent in significant concentrations only for annealing ramp rates greater than5 °C s−1.