Effects of irradiation damage on the back-scattering of electrons: Silicon-implanted silicon

Abstract

Radiation damage in a (initially crystalline) silicon wafer was generated by microbeam ion implantation with 600 keV Si+ ions (fluence 5 x 10(14) ions/cm(2)). To produce micro-areas with different degrees of damage, 14 implantations at different temperatures (between 23 and 225 degrees C) were done. The structural state of irradiated areas was characterized using Raman spectroscopy and electron back-scatter diffraction. All irradiated areas showed strong structural damage in surficial regions (estimated depth < 1 mu m), and at implant substrate temperatures of below 130 degrees C, the treatment caused complete amorphization. Back-scattered electron (BSE) image intensities correlate with the degree of irradiation damage; all irradiated areas were higher in BSE than the surrounding host. Because there were no variations in the chemical composition and, with that, no <(Z)over bar> contrast in our sample, this observation again supports the hypothesis that structural radiation damage may strongly affect BSE images of solids.