Shifting Schottky barrier heights with ultra-thin dielectric layers

Ultra-thin (similar to 1 nm) layers of dielectrics such as Al2O3 or SiNx inserted between the metal and the semiconductor can be used experimentally to shift the Schottky barrier height (SBH) of various semiconductors to reduce their contact resistance. This property is particularly valuable for n-Ge with a normally high n-type SBH or for nanowires. The mechanism is often described as Fermi level de-pinning. We show how the mechanism consists of two parts, Fermi level de-pinning plus an interfacial dipole layer. The preferred dielectrics can be chosen in terms of their band offsets. (C) 2011 Elsevier B.V. All rights reserved.