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Nanofabrication requirements for FIB technologies are specifically demanding in terms of patterning resolution, stability and the support of new processing techniques. Moreover the type of ion defines the nature of the interaction mechanism with the sample and thus has significant consequences on the resulting nanostructures [1]. Therefore, we have extended the technology towards the stable delivery of multiple ion species selectable into a nanometer scale focused ion beam by employing a liquid metal alloy ion source (LMAIS) [2]. This provides single and multiple charged species of different masses, resulting in significantly different interaction mechanisms. Nearly half of the elements of the periodic table are made available in the FIB technology as a result of continuous research in this area [3]. This range of ion species with different mass or charge can be beneficial for various nanofabrication applications. Recent developments could make these sources to an alternative technology feasible for nanopatterning challenges. In this contribution the operation principle, the preparation and testing process as well as prospective domains for modern FIB applications will be presented. As example we will introduce a GaBiLi LMAIS [4]. It enables high resolution imaging with light Li ions and sample modification with Ga or heavy polyatomic Bi clusters, all coming from one ion source. For sub-10 nm focused ion beam nanofabrication and microscopy, the GaBiLi-FIB or the AuSiGe-FIB could benefit of providing additional ion species in a mass separated FIB without changing the ion source. [1] L. Bruchhaus, P. Mazarov, L. Bischoff, J. Gierak, A. D. Wieck, and H. Hövel, Comparison of technologies for nano device prototyping with a special focus on ion beams: A review, Appl. Phys. Rev. 4, 011302 (2017). [2] L. Bischoff, P. Mazarov, L. Bruchhaus, and J. Gierak, Liquid Metal Alloy Ion Sources – An Alternative for Focused Ion Beam Technology, Appl. Phys. Rev. 3 (2016) 021101. [3] J.

In this talk we will review and detail the current status of EHD ion sources, also commonly referred as Liquid Metal Ion Sources, their development perspectives and their ever present expanding applicative domains. We will review the roots of this technology born in the early 70’s, deriving from space propulsion research, when physicists applied EHD phenomena onto liquid metal meniscus to create high brightness ion sources. Since then the LMIS qualities based on a remarkable brightness, excellent emission stabilities (current emission and emitting area invariance), ease of operation, lifespan and compactness small size were at the origin of the focused ion beam (FIB). As a deeply involved team in the pursuing quest aiming at investigating the full applied potential of the direct-write Focused Ion Beams technology since the mid-80’s, we will analyze and comment the never interrupted major effort invested around the world aiming at developing alternative ion sources. As a complement to the development of high current sources or atomic-sized emitters, we will show that high performance Liquid Metal Ion Sources and Liquid Metal Alloys Ion Sources exhibit definitive advantages at the prototyping level. We will analyze, quantify and describe the potential gains still to be expected from the widely used gallium LMIS and other alloy ion sources, that add a large number of ion species and patterning schemes. In conclusion we will summarize our vision on the future of FIB technology based on electro-Hydro Dynamically (EHD) driven emitters operating in the cone-jet mode, both in terms of performances, versatility and on the science frontiers these might help to push. My presentation will be an attempt to provide an overview on this FIB continuous evolution and future capabilities.

Focused Ion Beam (FIB) processing has been developed into a well established and still promising technique for direct patterning and proto-typing on the nm scale, high resolution imaging or high resolution ion lithography1. Exploring the Liquid Metal Alloy Ion Sources (LMAIS) potential represents a promising alternative to expand the global FIB application fields. Thanks to this, nearly half of the elements of the periodic table are made available in the FIB technology as a result of continuous research in this area during the last fifty years2. Recent developments could make these sources to an alternative technology feasible for nanopatterning challenges. Concerning ion beam resolution and minimization of unwanted damage, light ions like He or Li are preferred candidates. Liquid metal alloy ion sources (LMAIS) with a life time of more than 1000 µAh on the basis of Ga35Bi60Li5 and Sn95Li5 alloys were developed, characterized and finally applied in a commercial mass-separated VELION FIB-SEM system (Raith GmbH) 3. In the case of Li ions from the mass separated FIB a lateral resolution of 5.6 nm could be obtained in first experiments and the sputter yield was determined to 0.4 for 35 keV Li ions on Au. For reference, the helium ion microscope (HIM) has a lateral resolution of about 0.5 nm and 1.8 nm, for He and Ne respectively, He has a sputter yield of 0.14. For sub-10 nm focused ion beam nanofabrication and microscopy, the GaBiLi-FIB or the SnLi-FIB could therefore be considered alternatives to the HIM with the benefit of providing additional ion species in a mass separated FIB without changing the ion source. In this contribution the operation principle, the preparation and testing process as well as prospective domains for modern FIB applications will be presented1,5. As an example we will introduce a GaBiLi LMAIS in detail. It enables high resolution imaging with light Li ions and sample modification with Ga or heavy polyatomic Bi clusters, all coming from one io

In this article, the authors review, compare, and discuss the characteristics and applicative potential of a variety of nongallium ion liquid metal ion sources they have developed and successfully applied to nanopatterning. These sources allow generating on-demand ion beams and are promising for extending focused ion beams applications. They detail the operating characteristics of such sources capable to emit metal projectiles ranging from atomic ions with different charge states to polyatomic ions and to large metal clusters having sizes up to a few nanometers. They highlight their interest and relevance to current nanoscience challenges in terms of ultimate patterning or bottom-up nanofabrication capabilities.