Strong correlation between interface microstructure and barrier height in n-InP Schottky contacts formed by in situ electrochemical process

InP and related materials are attractive materials for high speed electronic and optoelectronic devices. Technologically, well-controllable metal/semiconductor (M/S) interface with high Schottky barrier heights (SBHs) in nano-scale are required for the realizability and the high reliability of nano-scaled electronic devices. However, metal/n-InP contacts generally produces low SBH values of typically about 450 meV. SBH values cannot be increased by using contact metals with large work functions due to so-called Fermi-level pinning. In contrast to this, we have recently shown that the SBH value of the Pt/n-InP contacts can be increased up to 860 meV by using an in situ pulsed electrochemical process. This process has also been shown to be useful for the Schottky gate formation for MESFETs and HEMTs. The purpose of this paper is to optimize the electrochemical process for high SBHs by investigating the correlation between the microstructures of metal/n-InP interfaces having nano-scale metal particles and the SBHs.