Gettering of Co in Si by high-energy B ion-implantation and by p/p(+) epitaxial Si

Detection and gettering of Co contamination in processed Si is an important issue in integrated circuit fabrication. In this work, Co was intentionall y introduced into Si by ion implantation, and its diffusion monitored by se condary ion mass spectroscopy. The surface layer recombination lifetime in p/p(+) epitaxial Si is unaffected by the Co at doses of 1x10(11) cm(-2) or 1x10(12) cm(-2). In the case of 2.5 MeV, 4x10(14) B/cm(2) ion implanted bul k Si, two mechanisms for Co redistribution during high temperature furnace, 900 degreesC, 30 min, processing are evident. First, regions of high boron concentration provide gettering sites for Co contamination. Second, the fi nal distribution of Co in Si reflects ion-implantation induced defect evolu tion during annealing. Both mechanisms will operate during device processin g and will control the effect of the metal on the electrical properties of the Si. (C) 2000 American Institute of Physics. [S0003-6951(00)03051-5].