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Characterization of silicon nanowires with NiSi2 Schottky contacts fabricated by top-down process
Deb, D.; Fuchs, F.; Georgive, Y. M.; Gemming, S.; Schuster, J.; Erbe, A.;
We report on characterization of reconfigurable, undoped silicon nanowire field effect transistors (FETs) with an axial heterostructure (metal/intrinsic-silicon/metal) fabricated on silicon on insulator (SOI) substrates by top-down process. Reconfigurable Si nanowire transistors with Schottky junctions can be reversely configured as p-FET or n-FET simply by the application of back gate electric signal. The fabrication scheme is based on electron beam lithography (EBL) using hydrogen silsesquioxane (HSQ), a negative-tone electron beam resist, followed by inductively-coupled plasma (ICP) etching. We produced silicon nanowires of 20 nm width and nanowire arrays with a pitch of ≈ 200 nm.
Nickel was sputtered on the Si nanowires at lithographically defined areas followed by thermal annealing to create nickel-silicide Schottky junctions inside the nanowires which also act as source-drain contacts. Diffusion of Ni in Si nanowires was precisely controlled by the radial crystal orientation of the nanowires, which was checked by transmission electron microscopy (TEM). TEM images show atomic sharp NiSi2-silicon junctions. Quantum transport simulations using non-equilibrium Green’s functions show changes in local density of states at the NiSi2-Si interface. Calculations also confirm that at the NiSi2-Si junction the Schottky barrier, heights for electron and holes are equal.
Keywords: NiSi2, Schottky Junctions, TEM
  • Poster
    Physics on Boat 2016, 31.05.-02.06.2016, Helsinki, Finland

Publ.-Id: 25030 - Permalink