Chapter 5 - Limits of Gate Dielectrics Scaling

Abstract

This chapter discusses limits of gate dielectric scaling for advanced metal oxide semiconductor field effect transistor (MOSFET). We will review details of hafnium oxide (HfO2) gate oxide and how HfO2 can be modified to hafnium oxynitrides (HfON) and hafnium lanthanum oxynitrides (HfLaON) to increase dielectric constant for continuous equivalent oxide thickness (EOT) scaling. Bilayer hafnium oxide/titanium oxide (HfO2/TiO2) as a higher ‘k’ dielectric option for FinFET gate length (Lg) scaling is discussed. Interfacial layer (IL) scaling technologies for overall EOT scaling are also covered in this chapter. Ab-initio modeling results to evaluate ternary and quaternary gate oxide for higher ‘k’ dielectrics options, and effective metal work functions calculations to optimize and develop new metal gates are discussed. New gate dielectric reliability failure mechanisms due to three dimensional natures of FinFET devices are reviewed.