An Attractive Candidate for Semiconductor Device Contact: 2-Dimensional Materials Inserted Metal/Semiconductor Interface

Abstract: Metal-semiconductor junctions are indispensable in semiconductor devices and have become a major limitation of performance improvement in recent years. Here, we report metal/n-Si Schottky contact barrier modification through the introduction of 2-dimentional (2D) materials, either graphene or hexagonal boron nitride (h-BN). The lowest specific contact resistivity (ρc) with 3.30 nΩ·cm2 (low-doped n-Si, ~1015/cm3) and 1.47 nΩ·cm2 (high-doped n-Si, ~1021/cm3) are achieved by using 2D insertion, which are difficult to reach with conventional techniques. Metal/2D/Si contact is demonstrated through the nm sized contact device on 6” wafer, including 2D process. The inserted 2D materials have two roles in metal/semiconductor contact; 1. 2D materials effectively changed the metal work function by dipole formation, 2. 2D materials changed the pinning point of Si to enable low Schottky barrier formation. The unique properties of 2D inserted contact are strongly influenced by the number of 2D layers and the Si interface, and the mono-layer and removal of native oxide are essential for optimum results. This proposed 2D inserted technique can be used as sub-nΩ·cm2 contacts for metal/n-Si, and will help break-through the CMOS technology.