Fabrication and Characterization of TiO_xMemristor for Synaptic Device Application

In this work, a two-terminal TiOx-based memristor device has been fabricated and the methods for controlling its conductance are demonstrated. The fabricated memristor device exhibits bipolar analog resistive-switching characteristics and the conductance margin over 10 fold between the highest and the lowest resistance states (RS). It is revealed that the conductance can be adjusted with high resolution by either continuous voltage sweep mode or pulse mode. In the former mode, the conductance is controlled as set/reset sweep stop voltages are changed by -0.2 V/ 0.2 V, respectively. In the latter method, the conductance is controlled by modulating the pulse width and amplitude. When the fabricated device is utilized as a synaptic device, consequently, the potentiation and depression operations start at voltages below -1.8 V and over 1.0 V, respectively. It has been found that the conductance changes and nonlinearity characteristics of weight update are tuned with various pulse widths and amplitudes. These results support that the fabricated memristor in a highly simple material configuration of Al/TiOx/Al can be a strong candidate for a synaptic device for the hardware-driven neuromorphic system as well as a novel nonvolatile memory device by the accurate conductance adjustability.