Carrier transportation mechanism of the TaN/HfO(2)/IL/Si structure with silicon surface fluorine implantation

Abstract

In this paper, the current transportation mechanism of HfO(2) gate dielectrics with a TaN metal gate and silicon surface fluorine implantation is investigated. Based on the experimental results of the temperature dependence of gate leakage current and Fowler-Nordheim tunneling characteristics at 77 K, we have extracted the current transport mechanisms and energy band diagrams for TaN/HfO(2)/IL/Si structures with fluorine incorporation, respectively. In particular, we have obtained the following physical quantities: 1) fluorinated and as-deposited interfacial layer (IL)/Si barrier heights (or conduction band offsets) at 3.2 and 2.7 eV; 2) TaN/fluorinated and as-deposited HfO(2) barrier heights at 2.6 and 1.9 eV; and 3) effective trapping levels at 1.25 eV (under both gate and substrate injections) below the HIM conduction band and at 1.04 eV (under gate injection) and 1.11 eV (under substrate injection) below the HfO(2) conduction band, which contributes to Frenkel-Poole conduction.