Application of mass-separated focused ion beams in nano-technology


Application of mass-separated focused ion beams in nano-technology

Bischoff, L.

During the last decades, the focused ion beam (FIB) became a very useful and versatile tool in microelectronics industry, as well as in the field of basic and applied research and derived an exceedingly importance with the development of the nano-technology. For special purposes like writing ion implantation for doping or ion beam synthesis (IBS) in the µm- as well as in the nm-range without any lithographic steps ion species other than gallium become more and more relevant. Therefore mass separated FIB systems equipped with alloy liquid metal ion sources (LMIS) play an increasing role.
So a Co-FIB obtained from a Co36Nd64 alloy LMIS was applied for the IBS at elevated sample temperatures and subsequent annealing for the fabrication CoSi2 nano-structures down to 20 nm on Si(111) and Si(100) substrates. The combination of FIB implantation (top-down approach) and self organization processes (bottom-up approach) during IBS can provide a spatial reduction of the locally implanted structures. A further investigated process is the defect induced formation of CoSi2 nanoparticles and nanowires using other ions than cobalt in the FIB (Au, Nd, Si, Ga), focused down to a spot diameter less than 30 nm at room temperature, and a Co deposited film on the rare side of the wafer. In this case crystalline CoSi2 nanowires of 10 – 30 nm diameter and a length up to some ten micrometer always aligned along the (110) orientations have been observed. These structures were studied using SEM/EDX and AFM analysis as well as by electrical characterization after contacting with W-pads, fabricated by FIB MO-CVD.
Other processes for the fabrication of nanstructures, like templating, 3D ion milling and the combination of FIB implantation and wet chemical anisotropic etching will be presented and discussed.
The high resolution mass separated Rossendorf FIB system, equipped with the CANION 31Mplus column (Orsay Physics) was applied with different (alloy) liquid metal ion sources (CoNd, AuSi, Ga) to demonstrate a emerging possibilities of nanostructure fabrication.

Keywords: mass-separated focused ion beams; alloy liquid metal ion source; nano-technology

  • Invited lecture (Conferences)
    18th International Conference on Ion Beam Analysis, 23.-28.09.2007, Hyderabad, India
  • Nuclear Instruments and Methods in Physics Research B 266(2008)8, 1846-1851

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Publ.-Id: 10351