Reliability characterization of stress-induced charge trapping in HfO2 by electrostatic discharge impulse stresses

Abstract

The charge trapping characteristics of HfO2 dielectric under the electrostatic discharge (ESD) high-field current impulses were studied. It is found that the charge trapping phenomenon is different from that of the conventional dc stress. The results show the interface-trapped charges are built at the low stress regime, but the positive oxide-trapped charges are rapidly built up while increasing the stress voltage, which eventually dominates the oxide breakdown. The origin of the positive oxide-trapped charges at the medium stress regime is most likely the hole trapping. At high stress regime, the main contribution of the positive oxide-trapped charges results from the electric-field enhanced defect generation. Using the Fowler derivative method, the degradation characteristics of HfO2 oxides under the ESD stress are investigated. Compared with SiO2, the severer ESD-induced charge trapping in HfO2 dielectric is observed which can be elucidated by the inherent bonding nature of metal oxide.