Mechanism and Conductance Range Enhancement of TiN/AlO_x/AlO_y/ITO Synaptic Devices

Abstract

Enhancement of the conductance range of memristors used in synaptic devices is essential for achieving high‐performance neural networks. Herein, a memristor based on the stack structure of TiN/AlO x /AlO y /ITO is designed to enhance the conductance range. The AlO x /AlO y devices exhibit pseudointerface switching characteristics with higher switching ratios and reliability under a compliance current of 1 mA. The high‐resistance state/low‐resistance state ratio of the AlO x /AlO y devices increases from 11.4 to 128.6 compared with the AlO x devices. Accompanied by high‐conductance linearity, the conductance range increases from 36–202 to 25–280 μS simultaneously. Based on the related electrical properties and microstructure analysis, the regulation mechanism of the formation and rupture of conductive filaments by the oxygen concentration gradient is demonstrated. Simulations using the Modified National Institute of Standards and Technology (MNIST) handwritten recognition data set prove that the AlO x /AlO y memristor can operate with a learning accuracy of 91.07%.