Boron cluster ions from source of negative ions by cesium sputtering

One of the ion implantation challenges for shallow junction formation is the production of high beam current at very low energy. Implantation of boron-containing clusters, such as Bn, SiBn, GeBn and B10H14 is a potential solution for this problem. Due to the higher cluster ion energy for the lower partial energy of the boron atom, the space-charge limit to the transport of the boron-containing cluster ion beams can be reduced by a factor of M/m, where M and m are the masses of the cluster and the boron atom, respectively. For a cluster of n boron atoms, the total gain in the cluster beam transport is n×M/m. In this paper, we will present new data on the extraction of boron-containing clusters with a Source of Negative Ions by Cesium Sputtering. For some clusters, the ion beam current can be increased by 1 to 2 orders of magnitude by adjusting the source parameters. Our experience in the successful extraction of boron-containing clusters may be useful in the design of high current ion sources.