Formation and Characterization of Filamentary Current Paths in $\hbox{HfO}_{2}$-Based Resistive Switching Structures

Abstract

In this letter, the progressive nature of the forming process step in HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -based resistive switching structures is investigated. Contrary to what happens with ramped or pulsed voltage stresses, current-driven degradation experiments shed light on the formation dynamics of the filamentary path across the oxide layer. The resulting voltage-current characteristics are interpreted in terms of electron transport through a mesoscopic constriction with adiabatic shape. The voltage decrease during the forming process is ascribed to a relaxation of the electron wavefunction confinement effect. The role of the compliance level on the leakage current magnitude is also discussed within this framework.