Forming-Free Tunable Analog Switching in WOx/TaOx Heterojunction for Emulating Electronic Synapses

Chandreswar Mahata; Juyeong Pyo; Beomki Jeon; Muhammad Ismail; Myounggon Kang; Sungjun Kim

doi:10.3390/ma15248858

Forming-Free Tunable Analog Switching in WO_x/TaO_x Heterojunction for Emulating Electronic Synapses

Materials (Basel). 2022 Dec 12;15(24):8858. doi: 10.3390/ma15248858.

Authors

Chandreswar Mahata¹, Juyeong Pyo¹, Beomki Jeon¹, Muhammad Ismail¹, Myounggon Kang², Sungjun Kim¹

Affiliations

¹ Division of Electronics and Electrical Engineering, Dongguk University, Seoul 04620, Republic of Korea.
² Department of Electronics Engineering, Korea National University of Transportation, Chungju-si 27469, Republic of Korea.

Abstract

In this work, the sputtered deposited WO_x/TaO_x switching layer has been studied for resistive random-access memory (RRAM) devices. Gradual SET and RESET behaviors with reliable device-to-device variability were obtained with DC voltage sweep cycling without an electroforming process. The memristor shows uniform switching characteristics, low switching voltages, and a high R_ON/R_OFF ratio (~10²). The transition from short-term plasticity (STP) to long-term potentiation (LTP) can be observed by increasing the pulse amplitude and number. Spike-rate-dependent plasticity (SRDP) and paired-pulse facilitation (PPF) learning processes were successfully emulated by sequential pulse trains. By reducing the pulse interval, the synaptic weight change increases due to the residual oxygen vacancy near the conductive filaments (CFs). This work explores mimicking the biological synaptic behavior and further development for next-generation neuromorphic applications.

Keywords: WOx/TaOx bilayer; gradual resistive switching; long-term potentiation; short-term plasticity; spike-rate-dependent plasticity; synaptic plasticity.

Grants and funding

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2018R1A6A1A03023788), and the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government (MOTIE) under Grant 20224000000020.