Effective Schottky barrier height and interface trap density reduction engineering using 2-dimensional reduced graphene oxide interlayer for metal-interlayer-semiconductor contact structure

The contact resistance at the metal-semiconductor (MS) interface has become the foremost challenge to ensuring high performance in nanoelectronics as devices are scaled down. A metal-interlayer-semiconductor (MIS) contact structure is a promising technique for Fermi-level unpinning to overcome the issue of fundamental contact resistance. Herein, an MIS contact structure with a 2-dimensional reduced graphene oxide (rGO) interlayer is proposed as an effective source/drain contact structure. The demonstration of a metal-rGO-semiconductor MIS (rGO MIS) contact structure with different interlayer thicknesses indicated that the rGO interlayer with a thickness of a few nanometers significantly enhanced the reverse current density (J_R) by ∼2.0 × 10³ times compared to that of the MS contact. In addition, the effective Schottky barrier height was reduced from 0.576 to 0.205 eV. This drastic improvement is attributed to the unique properties of rGO, such as its wide band gap, electrical conductivity, and Van der Waals interface leading to a metal-induced gap state reduction, tunneling resistance lowering, and passivation effect when it is adopted as an interlayer of the MIS contact. This result demonstrates the promising potential of using rGO as an MIS interlayer, which will pave the way toward high-performance emerging nanoelectronic devices.