A Schottky barrier field-effect transistor platform with variable Ge content on SOI

Abstract

Advancing SOI-based transistors with Ge-rich layers aims to increase device performance in terms of on-state operation and switching speed. Here, we investigate multi-heterojunction SiGe-based Schottky barrier FETs with Ge concentrations up to 75% by means of temperature- dependent electrical characterizations to identify the transport regimes and the effective barrier heights with a thermionic-emission-based model. Importantly, incorporating 33% Ge gives the best compromise for n- and p-type on-state symmetry. As the Ge concentration increases, the p-type on-state current becomes dominant, which is interesting for low-power p-type transistors.