Chemical tuning of band alignments for metal gate/high- κ oxide interfaces

Abstract

We report a method for chemical tuning of band alignments for metal gate/high- κ oxide interfaces. A heterovalent metal interlayer was included between the metal gate electrode and high- κ oxide. Based on our first-principles calculations for NiZr O2 (001) interfaces, a tunability as wide as 2.8 eV can be achieved for the effective work function of metal gate on high- κ oxide which far exceeds the required tuning range. In addition, we found a simple linear relationship between the effective metal work function and the electronegativity of interlayer metal atom for most of the transition metals considered. The localized interfacial dipole was found to dominate the contribution to the formation of Schottky barrier heights at metal/dielectric oxide interfaces. © 2006 The American Physical Society.