The application of FIB from mass separated alloy LMIS

During the last decades, the focused ion beam (FIB) became a very useful and versatile tool in the microelectronics industry, as well as in the field of research and development. For special purposes like writing ion implantation or ion mixing in the µm- or sub-µm range ion species other than gallium are needed. Therefore alloy liquid metal ion sources (LMIS) were developed. The energy distribution of the ions from an alloy LMIS is one of the determining factors for the performance of a FIB column. Different source materials like Au73Ge27, Au82Si18, Au77Ge14Si9, Co36Nd64, Er69Ni31, and Er70Fe22Ni5Cr3 were investigated with respect to the energy spread of the different ion species as a function of emission current, ion mass and emitter temperature. The alloy LMIS`s discussed above have been used for writing implantation to fabricate sub-µm pattern without any lithographic steps. A Co-FIB is applied for the ion beam synthesis of CoSi2 micro-structures down to 30 nm. Furthermore, a broad spectrum of ions was employed to study the sputtering process depending on temperature, angle of incidence and ion mass on a couple of target materials. Especially this direct patterning was used for the fabrication of various kinds of micro-tools as well as recently for nano-holes in AFM cantilever tips.
Running and future activities will be discussed which are focused to the preparation and investigation of plasmonic structures, like nano-wires and nano-chains in the sub-micron scale down to a few ten nanometers.