Vacancy-modulated self-rectifying characteristics of NiOx/Al2O3-based nanoscale ReRAM devices

A vacancy-modulated self-rectifying resistive random access memory (ReRAM) with a Ti/NiOx/Al2O3/Pt structure is proposed in this study. Here, NiOx is used as a resistive switching layer, and Al2O3 is used as a tunnel barrier layer for producing self-rectifying behavior. The tunnel barrier thickness in the NiOx/Al2O3 interfacial region can be increased or decreased according to the movement of oxygen vacancies in the NiOx layer under positive or negative voltages, respectively, thereby leading to self-rectifying resistive switching behavior. As a result, the NiOx/Al2O3-based self-rectifying ReRAM exhibits a low operation current of similar to 3 x 10(-7) A, large ON/OFF ratio of similar to 6 x 10(3), high rectification ratio of similar to 5 x 10(2), long retention of 10(5) s, and forming-free and self-compliance characteristics, meeting the next generation ReRAM requirements. The Ti/NiOx/Al2O3/Pt-based self-rectifying structures can pave the way to develop high-density embedded memory applications in the future. (C) 2019 Elsevier B.V. All rights reserved.