Implementation of Physical Reservoir Computing in a TaO_x/FTO-Based Memristor Device

Abstract

As one of the solutions to overcome the current problems of computing systems, a resistive switching device, the TiN/TaOx/fluorine-doped tin oxide (FTO) stacked device, was fabricated to investigate its capability in embodying neuromorphic computing. The device showed good uniformity during the resistive switching phenomenon under time and cycle-to-cycle dependent switching, which may be due to the oxygen reservoir characteristics of the FTO bottom electrode, storing oxygen ions during resistive switching and enhancing the device property. Based on the uniform switching phenomenon of the TiN/TaOx/FTO device, the pulse applications were performed to seek its ability to mimic the biological brain. It was revealed that the volatile and non-volatile nature of the device can be altered by controlling the pulse stimuli, where strong stimuli result in long-term memory while weak stimuli result in short-term memory. To further investigate the key functions of the biological brain, various learning rules such as paired-pulse facilitation, excitatory postsynaptic current, potentiation and depression, spike-rate dependent plasticity, and spike-time dependent plasticity were tested, with reservoir computing implemented based on the volatile characteristic of the TiN/TaOx/FTO device.

Keywords

• neuromorphic
• resistive switching
• spike-time dependent plasticity
• number recognition system
• reservoir computing