Non-Alloyed Ohmic Contacts on GaAs Using Metal-Interlayer-Semiconductor Structure With SF6 Plasma Treatment

Abstract

We demonstrate the effect of SF6 plasma passivation with a ZnO interlayer in a metal-interlayer-semiconductor (MIS) structure to reduce source/drain (S/D) contact resistance. The interface trap states and the metal-induced gap states causing the Fermi-level pinning problem are effectively alleviated by passivating the GaAs surface with SF6 plasma treatment and inserting a thin ZnO interlayer, respectively. Specific contact resistivity exhibits similar to 10(4) x reduction when the GaAs surface is treated with SF6 plasma, followed by ZnO interlayer deposition, compared with the Ti/n-GaAs (similar to 2x10(18) cm(-3)) S/D contact. This result proposes the promising non-alloyed S/D ohmic contact for III-V semiconductor-based transistors.