Temperature Dependent Schottky Contacts to InP and GaAs

Abstract

ABSTRACTThe barrier height of a Pd/n-InP diode was found to be increased from 0.48 to 0.96eV with the substrate temperature decreased from 300 to 77K during metal deposition. The leakage current density was reduced by more than six order of magnitude. It is obvious that the interface Fermi-level position lies well outside the variance associated with Fermi-level pinning. The barrier height for the Au/n-GaAs diode was found to be increased by about 0.25 eV with low temperature deposition and the leakage current reduced by more than five orders of magnitude. The mechanism responsible for the ultrahigh barrier height obtained at low substrate temperature was investigated by Raman spectroscopy, current voltage temperature measurement, deep level transient spectroscopy, and electroreflectance technique. The metal-insulator-semiconductor (MIS)-like structure formed at low substrate temperature and the reduction of interface state density may be the main reason for the dramatic enhancement of Schottky barrier height.