ION SOURCES FOR ION-IMPLANTATION AND ION-BEAM MODIFICATION OF MATERIALS

Industrial applications of ion beams began in the 1970s with their application in fabrication of semiconductor devices. Since electronic characteristics of semiconductors are very sensitive to the amount of doped elements and to the species, the ion beams should be precisely mass separated. Nowadays, ion implantation is expected to be used for surface modification of materials. For this the needed beam purity is lower, but the needed dose is higher, since mechanical and/or chemical characteristics of materials, which are less sensitive to the dose, should be improved rather than electronic ones. Mass resolution by a separator may be lowered to allow mixing of some neighboring elements and in some cases mass separation may be completely eliminated. Many ion sources have been developed for such applications; however, most were used for research work. In this paper, some of the typical ion sources are reviewed from the viewpoint of future industrial use.