A forming-free bipolar resistive switching behavior based on ITO/V2O5/ITO structure

Abstract

Forming-free bipolar resistive switching behavior in an ITO/V2O5/ITO structure is observed. While the bottom ITO layer functions as a common ground electrode, the top ITO layer is an active element and used as an oxygen reservoir, with an additional metal electrode patterned on its top for making contact. In contrast to typical metal/transition metal oxide/metal based resistive memories, our device exhibits a low resistance state in its virgin state and is switched to a high resistance state when a forward bias of ∼+2.5 V is applied. The device can be reset to its original state at a reverse bias of ∼–1.5 V. A noticeable decrease in switching voltage with a reduced top contact area is observed, indicating a strong electric field enhanced switching mechanism. Different from the widely seen conductive filament mechanism in bipolar switching, we explain the switching behavior by the migration of oxygen ions at the top ITO/V2O5 interface. When oxygen ions are extracted to the ITO side, an interfacial layer with reduced oxidation states is formed and acts as a Schottky barrier that suppresses the current through the whole device. The results suggest future applications in low power, high speed integrated non-volatile memories.

In Situ Nanostructural Analysis of Volatile Threshold Switching and Non‐Volatile Bipolar Resistive Switching in Mixed‐Phased a‐VOx Asymmetric Crossbars

“…However, this behavior has been reported previously for V 2 O 5 oxidation phase of a-VO x , [4,6] which is also present in our films as reported previously in Figure 1. However, this behavior has been reported previously for V 2 O 5 oxidation phase of a-VO x , [4,6] which is also present in our films as reported previously in Figure 1.…”

“…This kind of behavior has been reported before to occur in V 2 O 5 , [4,6] which is also present in our mixed phased a-VO x film. This kind of behavior has been reported before to occur in V 2 O 5 , [4,6] which is also present in our mixed phased a-VO x film.…”

“…This kind of behavior has been reported before to occur in V 2 O 5 , [4,6] which is also present in our mixed phased a-VO x film. [4] Exchange of oxygen ions creates barrier at the interface which is resolved by applying a voltage of opposite polarity. [4] Exchange of oxygen ions creates barrier at the interface which is resolved by applying a voltage of opposite polarity.…”

“…Wan et al [4] report the mechanism of forming-free BRS in a-V 2 O 5 as the exchange of oxygen ions at the TE (Ti) and oxide interface due to applied bias. [4] Although we observed similar forming-free non-volatile BRS as reported by Wan et al [4] we cannot be sure if it is due to V 2 O 5 component as our film is a mixed phase of three components as shown in Figure 1. [4] Although we observed similar forming-free non-volatile BRS as reported by Wan et al [4] we cannot be sure if it is due to V 2 O 5 component as our film is a mixed phase of three components as shown in Figure 1.…”

“…[1] The major disadvantage of 3D crossbars currently is the high-leakage or sneak-path current. [3] Depending on the stoichiometry, crystal structure, and device structure it has demonstrated bipolar resistive switching (BRS) [4][5][6][7][8][9][10] as well as apolar threshold switching (TS). [3] Depending on the stoichiometry, crystal structure, and device structure it has demonstrated bipolar resistive switching (BRS) [4][5][6][7][8][9][10] as well as apolar threshold switching (TS).…”