Improved electrical characteristics of Al2O3/InP structure by combination of sulfur passivation and forming gas annealing

The capacitance-voltage (C-V) characteristics of a Al2O3/InP capacitor fabr icated by helicon-wave excited O-2-Ar plasma oxidation of vacuum-evaporated Al were significantly improved by a combination of sulfur passivation of t he InP substrate in (NH4)(2)S-x (for 60 min) and post-thermal annealing in forming gas (FG) containing 5% H-2 (at 350 degrees C) Of the grown films af ter plasma oxidation. X-ray photoelectron spectroscopic (XPS) data indicate d the formation of In-S bonds and suppression of InP oxidation after the su lfur passivation. The reason for the improved C-V characteristics is briefl y discussed as being due to the termination of the incomplete or dangling b onds by sulfur and hydrogen.