Range and Damage Distribution in Cluster Ion Implantation

Abstract

AbstractCluster ion implantation is an attractive alternative to conventional ion implantation, particularly for shallow junction formation. It is easy to obtain high-current ion beams with low equivalent energy using cluster ion beams. The implanted boron distribution in 5keV B10H14 implanted Si is markedly shallower than that in 5keV BF2 ion implanted Si. The implanted depth is less than 0.04 μm, indicating that cluster ion implantation is capable of forming shallow junctions. The sheet resistance of 3keV B10H14 implanted samples falls below 500 Ω/sq after annealing at 1000°C for 10s. Shallow implantation can be realized by a high energy cluster beam without space-charge problems in the incident beam. Defect formation, resulting from local energy deposition and multiple collisions, is unique for cluster ions. The thickness of the damaged layer formed by cluster ion bombardment increases with the size of the cluster, if implant energy and ion dose remain constant. This is one of the nonlinear “cluster effects,” which may allow some control over the implant damage distributions that accompany implanted ions, and which have been shown to have a great effect on dopant redistribution during annealing