Traps and trapping phenomena and their implications on electrical behavior of high-k capacitor stacks

The traps and trapping phenomena and their implications on leakage currents, conduction mechanisms, and stress-induced leakage current in high-k dielectrics have been investigated. Various dielectrics (mostly multicomponent materials) have been studied to demonstrate the large diversity of phenomena that govern the electrical behavior of the structures depending on dielectric material, trap and stack parameters, and measurement conditions. The effects common for the most of high-k dielectrics and those typical for each individual structure have been discussed. The singly positively charged oxygen vacancy has been elucidated as the main electron transport site in the high-k materials. The role of the pre-existing traps for the electrical degradation of high-k stacks has been evidenced.