Defects and defect relaxation at internal interfaces between high-k transition metal and rare earth dielectrics and interfacial native oxides in metal oxide semiconductor (MOS) structures

Composite gate dielectrics for advanced Si devices that include high-k dielectrics have two interfaces that determine performance and reliability: (i) the Si-SiO2 interface, and (ii) the internal interface between SiO2 and the high-k dielectric. Spectroscopic studies combined with ab initio electronic structure calculations and bond constraint theory (BCT) identify quantitative relationships between electronic and/or mechanical strain and densities of defects and defect precursors at these interfaces. Discontinuities in the number of bonds/atom, Nav at these dielectric interfaces introduce high densities of defects that scale as the square of Nav. BCT also explains the driving force for nano-scale self-organizations at these interfaces, and the effect this has on defect densities, and other interfacial properties.