Cupper doping effect on the electrical characteristics of TiO2 based Memristor

Abstract

Nanostructures as a starting point to solve the scaling problems of the CMOS technologies, have been concerned the attention of numerous researchers. By strong demanding for nonvolatile memory technology, resistive memories based on metal oxide has been common due to several advantages, such as low-power consumption, good scalability and fast switching speed. Even though high-temperature fabrication process has a large area limitation by their material characteristics. Metal oxide thin films are respectable candidate to fabricate at nano scale solid state electronic device. Metal/Metal-Oxide/Metal structure is employed to several devices such as Non-volatile able memories, RRAMs, resistance switching based devices and memristor. The foundation of the primary TiO2 based memristor served a number of consequences for understanding the conduction mechanisms during the formation of hysteresis loop. Also, the current-voltage characteristics (hysteretic loop) which is formed by mobile anions or oxygen vacancies motion in the set and reset process, is clarified the resistive switching behavior by swapping the resistance of TiO2 thin film. Here, the effect of Cu doping into TiO2 based memristor by focused on the hysteresis loop characteristics is considered. Similarities of hysteresis loop form in Cu doped devices are explored. Hysteresis loop is symmetric for structures having pure TiO2; however, asymmetric character appears after Cu doping. After the formation process hysteresis loop of the Cu doped devices shown higher conductance path on (I-V) characteristic than the initial forming process loop in positive cycle loop as the un-doped TiO2. Also, in spite of un-doped TiO2, this (I-V) hysteresis loop character shown lower path conductance than primary forming process in the negative cycle loop. Surface roughness of 30nm thick TiO2 is increased from 0.3nm to 0.77nm as Cu doping increased from %10 to %30. Unfortunately, XRD results cleared that there is no exchange in crystallinity but optical band gap decreased as Cu doping increased.