On the dc and noise properties of the gate current in epitaxial Ge p -channel metal oxide semiconductor field effect transistors with TiN∕TaN∕HfO2∕SiO2 gate stack

Abstract

In this paper, we report the dc and noise properties of the gate current in epitaxial Ge p-channel metal oxide field effect transistors (pMOSFETs) with a Si passivated surface. The gate stack consists of HfO2∕SiO2 dielectric with TiN∕TaN metal gate. The observed temperature dependence of the gate current indicates that the dominant charge transport mechanism through the gate dielectric consists of Poole–Frenkel conduction. Gate current 1∕f noise is more than two orders higher in the case of Ge pMOSFETs when compared to reference Si pMOSFETs⁠. Ge outdiffusion into the gate oxide is the suspected cause for the enhanced Poole–Frenkel conduction and the high gate current 1∕f noise in Ge pMOSFETs⁠.