Behavior of Transition Metals Penetrating Silicon Substrate through SiO 2 and Si 3 N 4 Films by Arsenic Ion Implantation and Annealing

Abstract

The behavior of metals penetrating the silicon substrate through a screen SiO2 or Si3N4 film by the collision of arsenic ion and surface metals are quantitatively demonstrated. We have found using silicon step etching followed by ICP-MS and SIMS that 0.1 similar to 8% of surface metals (Fe, Cr, Ni, Cu, and W) penetrate silicon even when implanted through screen SiO2 film, depending on metal species and the film thickness. The surface metals on a CVD Si3N4 film can also penetrate into the silicon during ion implantation and/or subsequent annealing. W is most difficult to penetrate the thermally-grown SiO2 film, while W and Cr can easily penetrate a CVD Si3N4 films. We have also found using microwave photoconductive decay measurements that recombination centers are generated in silicon by low level metal penetration even when implanted through screen SiO2. (C) The Author(s) 2015. Published by ECS. All rights reserved.