Polaron-like Charge Trapping in Oxygen Deficient and Disordered HfO{sub}2: Theoretical Insight

摘要

We suggest that the polaron-like trapping of electrons is possible in the high-k dielectrics alongside with the commonly discussed Poole-Frankel resonant tunneling process or recapture of the electrons from the conduction band onto pre-existed defect states. The main feature of this mechanism is the charge self-trapping, i.e. formation of a localized defect state as a result of the electron-lattice interaction. We consider charge trapping properties of single oxygen vacancies and di-vacancies in the m-HfO{sub}2 as well as various models for oxygen deficient and stoichiometric disordered hafnia. We find evidence of polaronic trapping in all these systems, which may indicate its universality in high-k materials.