DOI: 10.1002/adem.201400577 TEM Study of Schottky Junctions in Reconfigurable Silicon Nanowire Devices ** By Sayanti Banerjee,* Markus L € offler, Uwe Muehle, Katarzyna Berent, Andr  e Heinzig, Jens Trommer, Walter Weber and Ehrenfried Zschech The physical and electrical properties of a silicon nanowire reconfigurable field effect transistor (RFETs) are determined by the Schottky junction between the participating phases. TEM studies on such junctions require a careful FIB-based target preparation of thin lamellae with minimal ion-beam induced damage. In the current study, the nickel silicide phase forming the Schottky junction with silicon is identified using EDX in the TEM, considering a calibration based on the Fourier transforms of the HRTEM micrographs of known diffraction patterns of the nickel silicide phases. The TEM lamellae are prepared using the so-called lift-out technique and low voltage Ga þ ion polishing to minimize the near-surface amorphization. The structural and compositional data of the nickel silicide phase are needed for engineering the Schottky junction and corresponding theoretical modeling. 1. Introduction Considering the unique properties of silicon nanowires and the expertise of semiconductor industry in silicon processing, silicon nanowires are a potential approach for “beyond CMOS” devices and building blocks for future technology nodes. Si nanowire RFET as described by Heinzig et al. [1] and Mikolajick et al. [2] have the functionality of p-type and n-type FETs in a single device. This device concept allowing a system reconfiguration at the hardware level has a huge potential to increase the system functionality. The key elements of a functional RFET are the NiSi 2 /Si Schottky junctions, which dictate the p-n junction character- istics and also the reconfigurability of these transistors. The process flow from the pristine nanowires to the implementa- tion into the device is described by Weber et al. [3–5] In this study, the nickel silicide phase forming the Schottky junction with silicon is identified using EDX in the TEM. To minimize the effect of sample amorphization, low voltage ion thinning within a FEI Helios Nanolab 660 SEM/FIB dual beam tool and sample extraction applying the FIB liftout technique are used for the preparation of the TEM lamellae. 2. Experimental Section The silicon nanowires were synthesized by the vapor– liquid–solid (VLS) growth mechanism on Si substrates, and then dispersed in alcohol and spray coated on a Si/SiO 2 insulating substrate. Subsequently, Ni is selectively deposited on both sides of the nanowires by electron beam lithography. Then the sample is annealed for 40 s at 450 °C in forming gas atmosphere to promote nickel interdiffusion and correspond- ing silicidation. The silicidation, that is, the formation of silicides from the Ni reservoirs at both ends of the nanowire and the Si of the nanowire, is the final process step to form NiSi 2 /Si Schottky junctions. [*] S. Banerjee, W. Weber, E. Zschech, A. Heinzig Technische Universit€ at Dresden, Center for Advancing Electronics Dresden (cfaed), Germany S. Banerjee, M. L€ offler, K. Berent, E. Zschech Technische Universit€ at Dresden, Dresden Center for Nano- analysis (DCN), Dresden, Germany E-mail: Sayanti.Banerjee@TU-Dresden.de U. Muehle, E. Zschech Fraunhofer-Institut f€ ur Keramische Technologien und Systeme - Institutsteil Material Diagnostik, Dresden, Germany K. Berent Institute of Metallurgy and Material Science, Polish Academy of Science, Krakow, Poland AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, Krak ow, Poland W. Weber, J. Trommer NaMLab gGmbH, Dresden, Germany [**] The work is partly supported by the German Research Foundation (DFG) within the Cluster of Excellence “Center for Advancing Electronics Dresden.” Markus L€ offler acknowl- edges the German Federal Ministry for Science and Education (BMBF) for financial support within the “MaKiZu” project. Katarzyna Berent thanks Technische Universit€ at Dresden for a grant within the Dresden Fellow initiative. The author byline and affiliation has been amended on July 1, 2015. 180 wileyonlinelibrary.com © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ADVANCED ENGINEERING MATERIALS 2016, 18, No. 2 FULL PAPER