The development of liquid metal ion source (LMIS) technology for use in electro-optical lenses has been largely responsible for the significant growth of interest in focussed ion beam (FIB) systems and their applications during the last decade. Among the earliest work, using capillary nozzle sources, an ion microprobe for surface analysis was developed (1), but following the invention of the needle LMIS (2), most applications work was concentrated upon the use of FIB systems of relatively high energy for ion beam lithography of submic'ron structures in resist (3,4). More recently, the emphasis of microfabrication work has shifted away from resist exposure towards direct FIB implantation doping, requiring the development of dopant-bearing alloy LMIS's (5,6). Most groups have adopted the use of EXB Wien filters (5,7) to separate the dopant ion from the beam, with one notable exception where a symmetrical four sector magnetic filter has been used (8). Growth of interest in all aspects of the technology has been most noticeable in Japan where development of UHV systems for FIB doping of MBE - grown III-V semiconductor material for opto-electronic devices has been the major interest in FIB in a number of laboratories.
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