Thermal SiO2 gated Ge metal-oxide-semiconductor capacitor on Si substrate formed by thin amorphous Ge oxidation and thermal annealing

Abstract

The thermal SiO2 gated Ge metal-oxide-semiconductor (MOS) capacitor on Si substrate was accomplished by the direct oxidation of the amorphous Ge layer and a subsequent forming gas annealing. The epitaxial Ge on Si substrate shows the good crystallinity and the smooth interface with the thermal oxide. The oxide on the Ge layer is confirmed to have SiO2 bonding structure with tiny Ge content. The negligible hysteresis and the small frequency dispersion in C-V characteristics indicate the desirable oxide quality. The conduction mechanism through the oxide has been verified as Fowler–Nordheim tunneling with the conduction band offset of 2.81eV. Another intriguing point of this process lies in the fact that it provides a simpler and ultralarge scale integration-compatible approach to fabricate high-performance Ge MOS field effect transistors as compared with previous works.