Internal electric field formation in insulators under high-flux negative ion implantation

Ion-flux dependent nanoparticle formation is observed in silica glasses under high-flux 60 keV Cu⁻ implantation. Under the high-flux implantation, a strong electric field possibly forms in the glass, and may affect the nanoparticle formation via the solute diffusion processes. In this paper, the internal-field formation is evaluated based on a model for negative ion implantation, in which different diffusion lengths of electrons and holes cause the field. The calculated fields sustain more than 2000 nm in depth, although the ion range is less than 100 nm. The fields hardly depend on the ion flux and the maximum value is 3.3 kV/cm. Mechanism to create the internal field and a possibility of high flux effects are discussed.