Ab initio calculation of Effective Work Functions for a TiN/HfO2/SiO2/Si transistor stack

TL;DR

This paper employs ab initio methods to accurately compute the effective work function of a TiN/HfO2/SiO2/Si transistor stack, incorporating many-body effects and interface variations for improved device modeling.

Contribution

It introduces a comprehensive ab initio approach that includes many-body effects and interface composition variations to predict the effective work function in MOS transistors.

Findings

Predicted Weff of TiN on HfO2 is approximately 5.0 eV.

Incorporation of many-body effects improves accuracy of band offset calculations.

Method accounts for interface composition variations in the stack.

Abstract

Ab initio techniques are used to calculate the effective work function (Weff) of a TiN/HfO2/SiO2/Si stack representing a metal-oxide-semiconductor (MOS) transistor gate taking into account first order many body effects. The required band offsets were calculated at each interface varying its composition. Finally the transitivity of LDA calculated bulk band lineups were used and completed by MBPT bulk corrections for the terminating materials (Si and TiN) of the MOS stack. With these corrections the ab initio calculations predict a Weff of a TiN metal gate on HfO2 to be close to 5.0 eV.