[13a-A31-1~11] 6.3 Oxide electronics

[13a-A31-6] Local characterization of resistive switching in TaO_x thin films with a highly uniform structure

〇Atsushi Tsurumaki-Fukuchi¹, Masashi Arita¹, Takayoshi Katase², Hiromichi Ohta², Yasuo Takahashi¹ (1.IST, Hokkaido Univ., 2.RIES, Hokkaido Univ.)

Keywords:resistive switching memory, ReRAM, TaOx

Scanning probe microscopy (SPM) can be considered as one of the most effective way of characterizing resistive switching memory because defect migration in the materials, which causes the nonvolatile resistance change, has been thought to have very small working dimension of 10⁻⁸–10^–9 m. In local characterization of resistive switching by SPM, however, recent studies have revealed that extrinsic contributions from surface roughness and/or non-uniform distributions of the defect concentration can easily affect the properties, and understanding for the intrinsic mechanism is often degraded. In this study, we developed a highly uniform thin film of amorphous TaO_x with a very flat surface with atomic-scale roughness and controlled concentrations of oxygen vacancies in order to evaluate the resistive switching properties of TaO_x under no structural disturbance and shed light on the intrinsic mechanism. In the current–voltage characteristics measured with a conductive SPM probe, we observed clear hysteretic behaviors showing that resistive switching can be induced with the nanoscale contact. We also note that the resistive switching has a significant repeatability by voltage sweeping and no positional preference for the induction. We found that a significant amount of in-plane mass transport coincides with the resistive switching phenomenon and breakdown process. These results suggest that lateral migration of film atoms by thermophoresis effect has important roles in the restive switching and breakdown of TaO_x.