Concepedia

The Degradation Process of High-<inline-formula> <tex-math notation="TeX">$k~{\rm SiO}_{2}/{\rm HfO}_{2}$ </tex-math></inline-formula> Gate-Stacks: A Combined Experimental and First Principles Investigation

Ebrahim Nadimi, Guntrade Roll, S. Kupke, R. Öttking, Philipp Plänitz, C. Radehaus, Michael Schreiber, Rimoon Agaiby, Martin Trentzsch, Steve Knebel,

IEEE Transactions on Electron Devices · 2014 · 16 citations · 24 references

DOI

Concepts

SemiconductorsDevice ModelingElectrical EngineeringSemiconductor TechnologyEngineeringSemiconductor DevicePhysicsFirst Principles InvestigationDegradation ProcessStress-induced Leakage CurrentApplied PhysicsCondensed Matter PhysicsCombined ExperimentalSingle Event EffectsDifferent Dielectric StacksMicroelectronicsAtomic Scale Calculation

Abstract

Theoretical and experimental methods are applied to investigate the degradation of SiO 2 /HfO 2 gate-stacks in state-of-the-art MOSFETs. A combination of density functional theory and nonequilibrium Green's function formalism has been applied to the atomic scale calculation of the leakage current through SiO 2 /HfO 2 dielectrics. Samples with different dielectric stacks have been taken into account to study the thickness dependence of SiO 2 and HfO 2 on the leakage current. The calculated results show a good agreement with the leakage current and constant voltage stress measurements. The current influenced by oxygen vacancies, particularly in the high-k dielectric close to the SiO 2 /HfO 2 interface has been analyzed. Comparison between the measurement and simulation results show that oxygen vacancy defects in the HfO 2 are a likely cause for progressive stress-induced leakage current in MOSFETs with ultrathin high-k gate-stack.