Correlation between Controllability of Reset Current and Electrostatic Energy Released from the Self Capacitance of Cond
- PDF / 282,961 Bytes
- 5 Pages / 432 x 648 pts Page_size
- 30 Downloads / 149 Views
Correlation between Controllability of Reset Current and Electrostatic Energy Released from the Self Capacitance of Conducting Bridge Random Access Memory Kentaro Kinoshita1,2, Shigeyuki Tsuruta1, Sho Hasegawa1, Takahiro Fukuhara1, and Satoru Kishida1,2 1
Department of Information and Electronics, Graduate School of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori 680-8552, Japan. 2 Tottori University Electronic Display Research Center (TEDREC), 522-2 Koyama-Kita, Tottori 680-0941, Japan. ABSTRACT Physical properties of filaments in Cu/HfO2/Pt conducting-bridge memory (CB-RAM) were investigated basing on direct observation by conducting atomic force microscopy (C-AFM) and energy dispersive X-ray spectroscopy (EDS), R-T characteristics until liquid nitrogen temperature, and I-V characteristics both in air and in vacuum. As a result, physical picture of filaments in Cu/HfO2/Pt structures was revealed. Filaments consist of Cu containing large residual resistance and the cross-sectional area of the filament, Sfila, was roughly proportional to set voltage, Vset, even when current compliance was kept constant. Interestingly, resistivities of filaments are same among all the filaments in different samples and are invariant even after repetitive switching that changes resistance of the filaments. Cu/HfO2/Pt obeyed the universal relation that reset current, Ireset, is proportional to the inverse of resistance in a low resistance state, 1/RLRS, which is known to be applicable to oxygen-migration-based resistive switching memories such as Pt/NiO/Pt. Considering the invariance of resistivity of the filament, this suggests the fact that Ireset is decided dominantly by Sfila. In addition, it was suggested that moisture is necessary for dissolution and migration of Cu to form filaments. INTRODUCTION Conducting-bridge random access memory (CB-RAM) in which a solid electrolyte layer consisting such as of AgS and GeSe is sandwiched between electrodes of inert metal such as Pt and of active metal such as Cu and Ag is candidate for nonvolatile memory and switch for the next generation [1-5]. In spite of excellent characteristics such as simple structure, high-speed operation, and low power consumption, very low switching voltage of less than 0.1 V that results in bad data retention prevents practical use [1-5]. In this context, it was reported that the similar resistive switching with appropriate switching voltage of 1-2 V can be attained simply by replacing the solid electrolyte layer with metal oxide such as Ta2O5 [6, 7] and HfO2 [8]. Although migration of electrode material is being received as the switching mechanism, it is not easy to explain how electrode materials migrate in metal oxide that is not solid electrolyte. In this paper, physical properties of filaments in Cu/HfO2/Pt structures were characterized by direct observation using conducting atomic force microscopy (C-AFM) and energy dispersive X-ray spectroscopy (EDS), R-T characteristics until liquid nitrogen temperature, and I-V characteristics both in air a
Data Loading...
