Silicon to nickel‐silicide axial nanowire heterostructures for high performance electronics

Abstract

AbstractSilicon to nickel disilicide axial nanowire (NW) heterostructures have been fabricated and investigated extensively. To this end, intrinsic Si‐NWs were grown by chemical vapor deposition using Au as the catalyst. The Si‐NWs were contacted with Ni reservoirs so that upon annealing Ni diffused axially into the NWs. Single‐crystalline NiSi2 NW segments were formed at the diffusion path of Ni as proven by high‐resolution transmission electron microscopy images. Further, the axial NiSi2 to Si interfaces showed a sharpness of a couple of nanometers. Fully silicided NiSi2‐NWs had maximal resistivities of 98 μΩ cm and conducted current densities of up to 205 MA/cm2 before breakdown. Controlled silicidation from both NW ends gave NiSi2/Si/NiSi2 axial NW heterostructures, which were implemented to fabricate Schottky contact field effect transistors (FET). The n++‐substrate was used as a common back gate and the Si to NiSi2 interfaces formed the Schottky source‐ and drain‐(S/D) contacts to the active region. These Si‐NW SB‐FETs exhibited p‐type behavior, and current densities in the on state of up to 0.8 MA/cm2 for 1 V bias, the drain current could be modulated over a range of 107. Moreover, the use of thin gate dielectrics enabled inverse subthreshold slopes as low as 110 mV/dec. These data show an efficient gate control over the devices by only using a back gate, due to an enhanced gate field coupling to the tip‐like S/D‐Schottky contacts. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)