REDUCTION OF BORON TRANSIENT ENHANCED DIFFUSION IN SILICON BY LOW-ENERGY CLUSTER ION-IMPLANTATION

Future integrated circuits require shallow pn junctions with a depth b elow 50 nm and, therefore, low energy ion beams are necessary. Cluster ions can realize both goals of low-energy and high-current ion beams quite easily, because the kinetic energy of a cluster is shared among constituent atoms. Another advantage of cluster ion implantation is th at the substrate damage induced by ion bombardment can be controlled b y changing the cluster size. As a consequence, the transient enhanced diffusion (TED) of the dopant during annealing can be controlled in cl uster ion implantation. We have used the polyatomic cluster, decaboran e (B10H14) to form very shallow p(+) junctions. During 900 degrees C a nnealing, the diffusion of boron atoms implanted at 3 keV was strongly suppressed compared with that implanted at 10 keV implantation. The d ifference in defect distribution between 10 and 3 keV implantation cau sed the different annealing behavior. (C) 1998 Elsevier Science S.A. A ll rights reserved.