Surface Analysis of Thermally Growth Ge Oxide on Ge(100)

Abstract

The understanding of Ge oxidation is utmost importance in order to form the good quality dielectric/Ge interface in fabricating Ge Metal Oxide Semiconductor Field Effect Transistor (MOSFETs). In addition, the mechanism of Ge oxidation is still under intensive studies. For Silicon oxidation, Deal and Grove Model have been accepted to explain the Si Oxidation mechanism. The purpose of this paper is to report the mechanism of Ge oxidation at two different temperatures, 375 and 490°C and the detail of Ge oxide composition at Ge oxide/Ge interface. After wet chemical cleaning with HCl, the thermal oxidation was performed at temperature 375 and 490°C at atmospheric pressure. The thickness and composition of Ge oxide were measured with spectroscopic ellipsometry and x-ray photoelectron spectroscopy, respectively. It was observed that the n value extracted from a log-log plot of oxidation time versus oxide thickness was dependent on the oxidation temperature. The oxygen-deficient region was formed during thermal oxidation of Ge and the electronic states of suboxide component were observed in the region within 2.3eV above the top valence band. The novelty of this work is to investigate the kinetics oxidation of Ge and evaluate the composition of oxide layer after thermal oxidation that becomes useful information for the development of Ge MOSFETs.