Performance improvement of bilayer memristor based on hafnium oxide by Ti/W synergy and its synaptic behavior

• Published in: Vacuum 2024-09, Vol.227, p.113392, Article 113392
• Main Authors: Wang, Fei, Wang, Fang, Lin, Xin, Liu, Ping, Li, Zewen, Du, Hongshun, Chen, Xingbo, Hu, Kai, Wang, Yuchan, Song, Zhitang, Zhang, Kailiang
• Format: Article
• Language: English
• Subjects: Biological synapse; Conductive mechanism; HfO2/HfOx; Interface engineering; Ti/W synergy
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2024.113392

Bilayer and multi-layer structures can effectively improve the performance of memristors, but the oxide/metal interface during the resistance switching process affects its reliability and stability. In this work, the Pt/HfO2/HfOx/W and Pt/HfO2/HfOx/Ti/W memristors with a homogeneous bilayer structure are compared to systematically investigate the effect of interface engineering on bilayer hafnium oxide devices by inserting Ti buffer layer to construct Ti/W composite electrode. Compared with the stimulated oxidation of the W electrode, the device under the synergy of Ti/W composite electrode showed better switching uniformity (The resistance of the high-resistance state and reset voltage variation coefficient decreased from 83.1 % to 31.9 % and from 9.5 % to 5.6 %, respectively.) and robust endurance (>104 cycles). Meanwhile, some essential synaptic behaviors such as nonlinear transmission characteristics, paired-pulse facilitation, and spike-timing-dependent plasticity were mimicked by using different pulse stimuli. Subsequently, the resistance switching mechanism of the device under the Ti/W synergy was explored by combining the results of I–V curve fitting and material analysis. These results provided important experimental guidance and a theoretical basis for further optimization of electrode interfacial effect in the future. •Interface engineering based on the Ti buffer layer improves the stability of bilayer hafnium oxide memristor.•Ti and W participate in the oxygen exchange of the memristor switching process to realize Ti/W synergy.•Some essential synaptic behaviors of Pt/HfO2/HfOx/Ti/W device are mimicked by using different pulse stimuli.•The Ti/W synergistic effect model is proposed to elaborate the formation/rupture of the device's conductive filaments.