Control of Gate Metal Effective Work Functions and Interface Layer Thickness by Designing Interface Thermodynamics Based on Heteroatom Incorporation into High-k HfO_2 Gate Dielectrics

摘要

We have proposed a new approach for controlling both gate metal effective work functions and interface layer thickness at the same time based on the incorporation of hetero atoms into HfO_2 gate dielectrics. We investigated C atom incorporation into HfO_2 by the first principles calculations. The results indicate that additional C atoms in HfO_2 can reduce an interfacial SiO_2 layer, which also causes modification of a gate metal effective work function. Redesigning interface thermodynamics by incorporating hetero atoms can be a crucial recipe for controlling both gate metal work functions and thickness of interfacial SiO_2 layers in high-k gate stacks.