Electrical properties of nanoscale Au contacts on 4H-SiC

Abstract

Electrical properties of the contacts consisting of nanoscale junctions separated within the Debye length (multinanocontact) were characterized both experimentally and numerically. The reduction in contact size from micrometer into the nanometer scale led to a decrease in effective Schottky barrier height from 1.69 to 1.09 eV and a much higher reverse leakage current density. This originated from a narrower barrier height beneath the contact, resulting in the increase in the tunneling current. In a multinanoscale contact separated within Debye length, the current density was expected to be higher than that of individual nanocontact (single nanocontact). This was attributed by the facts that in the multinanocontacts, the peripheral area of the depletion region would be thicker than that of the single nanocontact due to the extension of each depletion width. Thus this causes the decrease in the tunneling probability through the edge of depletion region, leading to the decreased current density in the multinanoscale contact.