Alleviation of Fermi level pinning at metal-Ge interface with lattice-matched Si_xGe_(1-x-y)Sn_y ternary alloy interlayer on Ge

摘要

The impact of a silicon germanium tin (SixGe1-x-ySny) ternary alloy interlayer on the Schottky barrier height (SBH) of metal/Ge contacts with various metal work functions has been investigated. Lattice matching at the SixGe1-x-ySny/Ge heterointerface is a key factor for controlling Fermi level pinning (FLP) at the metal/Ge interface. The SixGe1-x-ySny ternary alloy interlayer having a small lattice mismatch with the Ge substrate can alleviate FLP at the metal/Ge interface significantly. A Si0.11Ge0.86Sn0.03 interlayer increases the slope parameter for the work function dependence of the SBH to 0.4. An ohmic behavior with an SBH below 0.15 eV can be obtained with Zr and Al/Si0.11Ge0.86Sn0.03-Ge contacts at room temperature. (C) 2018 The Japan Society of Applied Physics