[17p-B3-1~18] 6.1 強誘電体薄膜

17:30 〜 17:45奨励賞エントリー注目講演

[17p-B3-18] Single-Crystalline PbTiO₃-Based Ferroelectric Memristors for Synaptic Plasticity Emulation

〇(DC)李 海寧¹、木島 健^1,2、片岡 莉咲¹、山原 弘靖¹、田畑 仁¹、関 宗俊¹ (1.東大院工、2.（株）ガイア二クス)

キーワード：

強誘電性、メモリスタ、抵抗スイッチング

Herein, memristors using ferroelectric PbTiO₃-based thin films are experimentally developed, with a reservoir of oxygen vacancies induced during the fabrication process. The single-crystalline growth and epitaxial growth have been confirmed by X-ray diffraction φ-scan and reciprocal space mapping, respectively. The current-voltage characteristics reveal stable resistive switching behaviors even after 100 sweeping cycles, indicating highly repetitive resistive switching. Their resistive switching behaviors are also confirmed under different maximum voltages and various voltage step widths. The conduction mechanisms are studied by fitting different conducting models. With tunable resistances, several phenomena of analog switching, single-pulse facilitation, paired-pulse facilitation, short-term memory (STM), long-term memory (LTM), and spike-timing-dependent plasticity (STDP) in response to pulse training can be experimentally mimicked in PbTiO₃-based memristors.The dynamic transitions from STM to LTM can be observed under different training pulses, where each cycle of training contains 30 and 100 pulses, respectively. During a cycle of pulse training, the resistance undergoes a potentiation process under pulse stimuli and then decreases after the stimuli are removed. These pulse trainings clearly reveal the learning and forgetting processes. The memory level increases with the number of pulse stimuli, and these characteristics are analogous to human memory in the brain. A pronounced transition from STM to LTM is observable after repeated rehearsal of training. The functionality of STDP is achieved, indicating the capability of PbTiO₃-based memristors as practical artificial synapses. The STDP characteristics under varying spike amplitudes and durations have been explored.