In-Operando And Non-Destructive Analysis Of The Resistive Switching In The Ti/Hfo2/Tin-Based System By Hard X-Ray Photoelectron Spectroscopy

Resistive switching in Ti/HfO2/TiN was investigated in-operando by hard x-ray photoelectron spectroscopy. In comparison with the virgin-state, ON- and OFF-states show enhanced Ti/TiOx/HfO2 interface oxidation, resulting from an oxygen-gettering activity of Ti. The formed TiOx layer acts in the resistive switching process as an oxygen reservoir in exchange with the non-stoichiometric HfO2-delta. A Ti1+/Ti3+ valence change redox reaction occurs between OFF-and ON-states. The peak shifts are attributed to space charge potentials created by the varying oxygen vacancy concentration at the interface. A push-pull model of oxygen vacancies as a function of voltage polarity is proposed to describe the mechanism. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4756897]