Novel materials processing and applications. by gas cluster ion beams

Gas cluster ion beams are found to offer a number of new and important opportunities for processing of materials. Ultrashallow ion implantation by cluster ion beams has been demonstrated experimentally and confirmed by molecular dynamics simulations. Very high-rate sputtering, with sputtering yields of one or two orders of magnitude greater than those produced by monomer ion beams, has also been studied in detail. Surfaces sputtered by cluster ion beams become smoother when physical sputtering is provided by nonreactive gas species, but chemical sputtering by reactive gases does not produce the same reduction in roughness effect. The smoothing effects produced by cluster ions cannot be produced by monomer ion beams. Unique bombarding characteristics of cluster ion beams have been applied to the formation of source/drain shallow junctions for 40 nm p-MOSFETs, to high-yield etching and surface smoothing of Si, YBCO, diamond, and SiC substrates, and to the production of electronic and optical devices. A low-temperature thin-film formation technique by cluster ion-assisted deposition has also been developed for high-quality oxide films. This paper reviews recent equipment development and discusses several new applications.