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Application of the Helium Ion Microscope as a Sculpting Tool for Nanosamples Maria Rudneva1, Emile van Veldhoven2, Sairam Malladi1, Diederik Maas2, Henny W. Zandbergen1 1 Delft University of Technology, Kavli Institute of Nanoscience, Lorentzweg 1, 2628 CJ Delft, The Netherlands. 2 TNO - van Leeuwenhoek Laboratory, Stieltjesweg 1, 2826 CK Delft, The Netherlands. ABSTRACT In this paper we propose a few helium ion microscope (HIM)-based methods for sample preparation and modification. In particular we report the use of the HIM to make thin wedge SrTiO3 samples without significant artifacts, the possibility to reshape thin metal lines on an electron transparent membrane and the new method of HIM sample preparation by in situ heating of the samples during He-beam illumination. INTRODUCTION The helium ion microscope (HIM) was introduced in 2006 as a new high-resolution imaging tool [1]. The unique helium ion source can be regarded as the nearly ideal point source because it results in a subnanometer probe size and allows a large depth of view. Compared to other ions, He ions have a particular sample interaction that generates a relatively high number of low-energey secondary electrons and a low yield of backscatter ions, which allows the remarkable imaging of a range of samples, including samples with high charging [2, 3, 4]. It was soon realized that the HIM can also be used for nanofabrication. For instance, the helium ion microscope yields 4-nm-wide lines with a pitch of 10 nm when used for lithography [5, 6]. Very narrow structures with almost no overspray can be made with the gas-induced deposition [7]. For thin-film dicing and nano-pore drilling, sub-10-nanometer features are now achieved [8, 9]. The accelerated helium ions penetrate deeply into bulky samples. In Si, for example, this leads to amorphization, the formation of nanobubbles and even microbubbles when the doses are high [10]. In this article we present our latest results on nanoscale cutting of Si and SrTiO3 lamellas of various thicknesses at room and elevated temperatures. Also results of precise modification of thin Pt bridges with a helium beam are presented. EXPERIMENTAL Modification of silicon lamellas with a focused helium beam at different temperatures Silicon remains one of the most commonly used materials in the semiconductor industry. Ongoing development and miniaturization of semiconducting devices requires new techniques for sample modification and reparation in case of any possible failure or damage. Focused ion beam (FIB) microscopy using Ga ions has demonstrated good results for bulk samples so far. However, the lack of resolution, significant broadening of the beam near the surface and contamination of the sample with Ga ions makes Ga-FIB nanomodification of the samples nearly

impossible [11]. In that sense it is necessary to develop new cutting techniques that allow the sample to be modified on the scale of a few nanometers without causing significant damage or contamination. It is known that direct momentum transfer from charged part