Pt/Ti/Al2O3/Al tunnel junctions showing electroforming-free bipolar resistive switching behavior

TL;DR

This study demonstrates electroforming-free bipolar resistive switching in Pt/Ti/Al2O3/Al tunnel junctions, enabling multi-level resistance states through barrier modulation without the need for initial electroforming.

Contribution

It introduces a new resistive switching mechanism in tunnel junctions with naturally formed Al2O3 barriers, highlighting multi-level operation potential without electroforming.

Findings

Resistive switching occurs without electroforming.

Multiple resistance states achieved via compliance current.

Switching mechanism involves tunnel barrier modulation.

Abstract

We investigated electroforming-free bipolar resistive switching behavior in Pt/Ti/Al2O3/Al tunnel junctions where the Al2O3 tunnel barrier was naturally formed on Al in air. Various compliance current values for the junction's set switching successfully lead to various resistance values in its low resistance state, suggesting the possibility for multi-level-operation. A mechanism for the bipolar switching is qualitatively discussed in terms of the modulation of the tunnel barrier by the reactive Ti layer on top of the barrier.