Concept of single ion detector for deterministic ion implantation at the nanoscale

(1) Institute for Experimental Physics II, University of Leipzig, Linnéstr. 5, 04103 Leipzig, Germany, Joint Single Ion Implantation Lab, Permoserstr. 15, 04318 Leipzig, Germany
(2) Leibniz Institute of Surface Modification, Permoserstr. 15, 04318 Leipzig, Germany, Joint Single Ion Implantation Lab, Permoserstr. 15, 04318 Leipzig, Germany
(3) Max-Planck-Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany
(4) Institute for Experimental Physics II, University of Leipzig, Linnéstr. 5, 04103 Leipzig, Germany, Leibniz Institute of Surface Modification, Permoserstr. 15, 04318 Leipzig, Germany, Joint Single Ion Implantation Lab, Permoserstr. 15, 04318 Leipzig, Germany
(5) Institute for Experimental Physics II, University of Leipzig, Linnéstr. 5, 04103 Leipzig, Germany, Joint Single Ion Implantation Lab, Permoserstr. 15, 04318 Leipzig, Germany

Nowadays, the ability to endow functionality to single atoms or molecules in materials becomes of increasing importance in nanotechnology. Atoms can be used as switches, single photon sources or quantum mechanical objects, e.g. for information processing and quantum computing. Deterministic ion implantation, i.e. the implantation of a counted number of ions, with a lateral accuracy of a few nanometers is one approach to achieve this goal. However, counting low-keV single ions with high detection efficiency is difficult - techniques used so far include secondary electron detection [1] or ion beam induced charge [2] caused by the ion impact. Ion traps have been used as single ion sources as well [3]. All these techniques have their individual limitations, e.g. the requirement for the implanted material to act as an efficient secondary electron emitter or particle detector or the restriction to specific atoms and substantial experimental effort in case of ion traps. Our planned approach to deterministic ion implantation uses a commercial Focused Ion Beam (FIB) system equipped with a dedicated single ion source. The latter one comprises an ion source, an E x B filter and a single ion detector which allows to detect the ion prior to injection into the FIB system, making the ion detection independent from the properties of the implanted material. We discuss the concept of a single ion detector which preserves the very low emittance of the ion source required for ion injection into the FIB.   

[1] T. Matsukawa et al., Appl. Surf. Sci. 117/118 (1997) 677
[2] J.C. McCallum et al., Adv. Mater. Sci. Eng. 2012 (2012) 272694 [3] W. Schnitzler et al., Phys. Rev. Lett. 102 (2009) 070501