Interface-controlled Schottky barriers on InP and related materials

Schottky barriers on InP and related material produced by conventional metal deposition processes are known to exhibit almost metal-independent low Schottky barrier heights (SBHs) caused by Fermi-level pinning phenomenon. It is shown in this article that removal of Fermi-level pinning and substantial increase of SBH values can be realized on InP-based materials by a controlled formation of Schottky interfaces using a novel, extremely low-energy, damage-free, in-situ electrochemical process. Increased SBHs of 0.89 eV, 0.50 eV and 0.89 eV are obtained for n-InP, n-In0.53Ga0.47As and n-In0.52Al0.48As, respectively, by electrochemical deposition of Pt. After briefly reviewing the Fermi level pinning phenomenon, details of the novel in-situ electrochemical process are presented together with some device applications. An attempt was made to explain the underlying mechanism for the observed SBH increases on the basis of the disorder-induced gap state (DIGS) model for Fermi-level pinning. (C) 1997 Elsevier Science Ltd.