Fermi level pinning and chemical interactions at metal/metal organic CVD grown GaAs interfaces: Schottky barrier height

Abstract

A systematic study designed to investigate the mechanism involved in Fermi level pinning on interfaces of metal organic CVD grown GaAs and various metals is reported. Transport properties (current-voltage (I-V), capacitance-voltage (C-V)) and X-ray photoelectron spectroscopy with emphasis on the Schottky barrier height φ_b of metal contacts (magnesium, manganese, aluminium, chromium, cobalt, nickel, tin, silver and palladium) to both p-and n-type GaAs have been measured. The dependence of φ_bnof the metal contacts to n-GaAs on the annealing temperature has also been studied by means of the I-V technique. It was found that there is an optimum temperature for maximum φ _bn because of chemical reaction at the metal-GaAs interface.