[10p-S203-1~21] 6.3 Oxide electronics

[10p-S203-2] Mechanisms of Analog Memristor Operations of Amorphous TaO_x Probed on the Atomically Flat Surfaces

〇Atsushi Tsurumaki-Fukuchi¹, Takayoshi Katase², Hiromichi Ohta³, Masashi Arita¹, Yasuo Takahashi¹ (1.IST, Hokkaido Univ., 2.MSL, Tokyo Tech., 3.RIES, Hokkaido Univ.)

Keywords:memristor, analog memory, tantalum oxide

Toward understanding the mechanisms of analog (memristive) resistive switching phenomena in amorphous TaO_x, which are critically important in neuromorphic applications, we fabricated atomically flat thin films of amorphous TaO_x on atomically stepped substrates of Nb:SrTiO₃ (001) (0.05 wt% Nb). On the surfaces, the ion migration involved in the analog resistive switching was investigated by conductive-probe atomic force microscopy (c-AFM). Thanks to the very uniform mechanical/electrical contacts at the tip/film interfaces, many types of analog resistive switching operations (such as current-dependent analog set and voltage-dependent analog reset) were demonstrated in the transport measurements with c-AFM tip. The important roles of the vertical ion migration by field-induced drift, lateral ion migration by thermal diffusion, and local reversible redox reactions were visually revealed in the processes of analog resistive switching.