Resistive switching characteristics in hafnium oxide, tantalum oxide and bilayer devices

Abstract

In our study, the devices with Pt/Ti/TaOx/Pt, where x ranges from 1.34 to 1.47, Pt/Ti/HfO2/Pt and Pt/Fi/TaOy/HfO2/Pt were fabricated. The TaOx and HfO2 were the switching layers for single layer devices and for hybrid device TaOy acted as oxygen reservoir and HfO2 acted as switching layer. The single layer devices exhibited co-existence of bipolar and unipolar switching. For bipolar switching the SET process occurred when positive sweep voltage was applied and RESET process occurred for negative sweep. The transition from bipolar to unipolar was observed to be irreversible. The hybrid device exhibited the unipolar switching with two high resistance state (HRS) levels. Moreover, the conduction mechanism of ohmic conduction, space charge limited conduction (SCLC); Schottky conduction and Poole-Frenkel (P-F) conduction have been investigated. (C) 2016 Elsevier B.V. All rights reserved.