Transition of short-term to long-term memory of Cu/TaOx/CNT conductive bridge random access memory for neuromorphic engineering

This work presents the resistive switching characteristics of the TaOx-based conductive-bridge random-access memory (CBRAM) for neuromorphic engineering. Controlling the Cu filament inside the TaOx film allows the device to operate as both volatile and nonvolatile memory. For volatile switching induced by a lower compliance current (Icc), a threshold switching operation is observed. Upon completion of the set process, the retention and current decay were observed, suggesting that the device has the potential for short-term memory applications. Increasing Icc enables the CBRAM to act as a memory-switching device, as confirmed by the lengthy retention time of up to 104 s. Additionally, short-term memory (STM) and long-term memory (LTM) of the device were demonstrated by time-dependent memory decay, where the various magnitude differences of the time-dependent operations. STM was identified by applying two identical pulses to the device to mimic the paired-pulse facilitation (PPF) of the neural system. Furthermore, long-term potentiation and depression were accomplished via consequent identical pulse stimuli under different switching modes to demonstrate stable LTM properties.

Automated summary

This work presents the resistive switching characteristics of the TaOx-based conductive-bridge random-access memory (CBRAM) for neuromorphic engineering. The device can operate as both volatile and nonvolatile memory by controlling the Cu filament inside the TaOx film. It shows potential for short-term memory and long-term memory applications.