Synaptic behaviors and modeling of a metal oxide memristive device

• Published in: Applied physics. A, Materials science & processing Vol. 102; no. 4; pp. 857 - 863
• Main Authors: Chang, Ting, Jo, Sung-Hyun, Kim, Kuk-Hwan, Sheridan, Patrick, Gaba, Siddharth, Lu, Wei
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.03.2011
• Subjects: Characterization and Evaluation of Materials; Condensed Matter Physics; Machines; Manufacturing; Nanotechnology; Optical and Electronic Materials; Physics; Physics and Astronomy; Processes; Surfaces and Interfaces; Thin Films; Schottky Barrier; Rapid Thermal Annealing; Tungsten Oxide; Oxygen Vacancy; Bottom Electrode
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-011-6296-1

Nanoscale memristive devices using tungsten oxide as the switching layer have been fabricated and characterized. The devices show the characteristics of a flux-controlled memristor such that the conductance change is governed by the history of the applied voltage signals, leading to synaptic behaviors including long-term potentiation and depression. The memristive behavior is attributed to the migration of oxygen vacancies upon bias which modulates the interplay between Schottky barrier emission and tunneling at the WO X /electrode interface. A physical model incorporating ion drift and diffusion effects using an internal state variable representing the area of the conductive region has been proposed to explain the observed memristive behaviors. A SPICE model has been further developed that can be directly incorporated into existing circuit simulators. This type of device can be fabricated with low-temperature processes and has potential applications in synaptic computations and as analog circuit components.