Low-resistance ohmic contacts to SiC nanowires and their applications to field-effect transistors

Abstract

We report on the electrical characterization of two ohmic contacts (Ti/Au and Ni/Au) to unintentionally doped silicon carbide nanowires (SiCNWs) using the modified transmission line model (TLM) method. Our results indicate that subsequently deposited Ni/Au ohmic contacts on SiCNWs had similar to 40 times lower specific contact resistances (SCRs) of 5.9 x 10(-6) +/- 8.8 x 10(-6) Omega cm(2) compared to the values of Ti/Au ohmic contacts (2.6 x 10(-4) +/- 3.4 x 10(-4) Omega cm(2)). We also conducted a comparison study of the electrical characteristics of top-gated SiCNW field-effect transistors (FETs) with two different ohmic contacts as used for ohmic contact studies. The electrical transport measurements on the SiCNW FET with Ni/Au ohmic contacts show much lower resistance contacts to SiC NWs and better FET performances than those for Ti/Au ohmic contact-based FETs.