Tunneling Properties of the Charge Carriers through Sub-2-nm-Thick Oxide in Ge/a - GeO2/Ge Structures Using the First-Principles Scattering-State Method

Abstract

To suppress gate leakage current in nanoscale field-effect transistors, quantum mechanical tunneling of carriers through the oxide in a metal-oxide-semiconductor structure must be minimized. Here the first-principles scattering-state approach is used to study tunneling through ultrathin oxide layers in Ge/$a$-GeO${}_{2}$/Ge structures. This work demonstrates the strong correlation among atomic structure, band-gap alignment, tunneling spectra, and tunneling current densities with respect to oxide thickness, interfacial structures, and Ge orientations. The informative results will impact MOSFET design and should be of great interest to the diverse community of semiconductor researchers.