Damage induced through megavolt arsenic implantation into silicon

Abstract

An arsenic beam of 11 MeV was used to achieve a layer of heavily doped silicon centered at 4.4 μ below the surface. Both liquid nitrogen and water-cooled (100) silicon substrates were exposed to an arsenic dose of 1.9×1015 ions/cm2. Before furnace annealing, cross-sectional transmission electron microscopy (XTEM) shows buried amorphous regions for both samples with a wider amorphous region for the LN-cooled sample. The depth distribution of secondary defects on subsequent annealing qualitatively resembles those obtained by lower energy implantation, and the details depend strongly on the substrate temperature during implantation. Secondary ion mass spectrometry (SIMS) was used to verify LSS calculations for the arsenic distribution.