Improvement of Al/GaAs Schottky junction characteristics using a thin praseodymium interlayer

A thin praseodymium interlayer with a thickness of less than 3.5 nm at the Al/GaAs Schottky junction is shown to reduce the reverse bias leakage curre nt by more than two orders of magnitude and enhance the Schottky barrier he ight by 0.12 eV. The significant reduction of reverse bias leakage current cannot be explained by the barrier height enhancement alone. Formation of i nterfacial praseodymium oxide and gettering of n-type dopant in GaAs substr ates by the praseodymium interlayer needs to be taken in to account to expl ain the results. Furthermore, it was found that the cut-in voltage of forwa rd current increases significantly with the Pr oxidation time, which is ver y useful in the fabrication of enhancement-type transistors for high-speed integrated circuits.