Bulk and Interface Engineering of GeO2/Ge for High-κ/Germanium Gate Stack

Abstract

Effects of germanium-monoxide desorption on both the interface and the oxide bulk of thermally grown germanium-dioxide as well as its controlling methods have been investigated. The density of interface states was increased and water absorbency of the oxide film was enhanced by the desorption. The density of positive charge strongly depends on amount of water molecules in the oxide. Moreover, the flat-band voltage shift due to the positive charge, which can be generated at a given electric field from donor-like traps, increases linearly with the maximum field in the oxide. It was found that suppression of both the germanium-monoxide desorption and the water absorption are the keys for fabrication of high-quality germanium-dioxide film as an inter-layer of the high-κ/germanium gate stack.