Improved resistive and synaptic switching performances in bilayer ZrOx/HfOx devices

• Published in: Journal of alloys and compounds 2023-11, Vol.962, p.171096, Article 171096
• Main Authors: Ji, Hyeonseung, Lee, Yoonseok, Heo, Jungang, Kim, Sungjun
• Format: Article
• Language: English
• Subjects: AI semiconductor; Bilayer device; Neuromorphic system; Resistive switching; Synaptic device
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2023.171096

In this study, we investigated the resistive switching (RS) characteristics of ZrOx/HfOx bilayer-based resistive random-access memory (RRAM) devices. A 1.5-nm-thick HfOx layer was deposited by atomic layer deposition (ALD) between the ZrOx layer and TiN electrode to enhance the RS. Compared to the ZrOx single-layer device, the bilayer device exhibited a lower high resistance state (HRS) current, which improved endurance and reduced energy consumption due to the insulating HfOx layer. In addition, a DC endurance of 300 cycles and strong retention characteristics (10,000 s) were achieved in the bilayer device. Furthermore, the multi-level cell (MLC), potentiation, and depression characteristics were evaluated to demonstrate the suitability of the Ti/ZrOx/HfOx/TiN device for use as a neuromorphic device. With regard to potentiation and depression, various pulse schemes were employed to improve the asymmetric conductance changes for neuromorphic system applications. •Double oxide based memristor device was designed.•TEM analysis provide thickness of the films.•MLC was implemented by pulse as well as DC sweep.•Switching mechanism was explained by bang gap and chemical properties.•System level neuromorphic simulation was conducted.