Bulk and Interfacial Oxygen Defects in HfO2 Gate Dielectric Stacks: A Critical Assessment

Oxygen-related point defects can provide fixed charge or act as charge trapping centers in high-k gate stacks and, therefore, their origins and properties are of great interest. In this paper, reported experimental and theoretical results related to oxygen defects in HfO2 gate dielectrics are reviewed critically to assess the relative importance of different defect species in terms of their electrical activity and their contributions to important kinetic processes. In addition to point defects in the “bulk” of HfO2 thin films, defects resulting from differences in oxygen coordination across the internal hafnium oxide/silicon oxide interface are considered.