High performance bi-layer atomic switching devices

Abstract

Atomic switches, also known as conductive bridging random access memory devices, are resistive-switching devices that utilize the electrochemical reactions within a solid electrolyte between metal electrodes, and are considered essential components of future information storage and logic building blocks. In spite of their advantages as next generation switching components such as high density, large scalability, and low power consumption, the large deviations in their electrical properties and the instability of their switching behaviors hinder their application in information processing systems. Here, we report the fabrication of a uniform, low-power atomic switch with a bi-layer structure consisting of TaO as the main switching layer (SL) and a relatively oxygen-deficient TaO as an oxygen vacancy control layer (VCL). The depth profiles of the filaments in the bi-layer device were obtained by performing conductive atomic force microscopy to assess the improvements in uniformity, reliability, and electrical performance that result from the insertion of the VCL. The coefficient of variation of the high resistance state of the bi-layer device was found to be drastically reduced from 60.92% to 2.77% in the cycle-to-cycle measurements and from 82.73% to 4.85% in the device-to-device measurements when compared with the values obtained for a single-layer device. The bi-layer device also exhibits a forming-free low operation voltage of ∼0.4 V, a high on/off ratio of ∼10, and high reliability with 10 years data retention at 85 °C.

Oxide-Electrolyte Thickness Dependence Diode-Like Threshold Switching and High on/off Ratio Characteristics by Using Al2O3 Based CBRAM

“…The extremely high on/off ratio is promising for multilevel switching [31,32] and future neuromorphic computing to ensure the enhance conduction states. Though the device is unable to go for long P/E endurance keeping such a high order on/off ratio, still this result is comparable with recently published works as listed in Table 1 [10,11,[33][34][35][36][37][38]. By reducing pulse width from 500 µs to 1 µs, P/E cycles are improved to 100 P/E cycles, as shown in Figure 7b.…”

“…After formation of the pristine devices, a reduction and oxidation at the neck region will be responsible for LRS and HRS of the devices. For the S2 devices, the high electric filed controls across [11] 7/−9 0.1/10 5/5 10 7 10 5 10 6 Cu/TaO x /Ta 2 O 5-x /Pt [33] -/-0.1/0.1 -3000~10 5 >10 4 at 85 • C Cu/HfO 2 :Cu/Pt [34] -/-1/1 0.01/100 >100 10 7 10 5 Al/CH 3 NH 3 Pbl 3 :PVA m.Hl/ITO/Glass [35] 3/−1 100/100 10 4 /10 4 500 >10 5 10 4 Cu/Ti/PVP-PMF/Pt [36] 1/−0.5 1/5 10 4 /10 4 >10 3 >10 3 >10 3 at 85 • C Ag/HfO x :N/Pt [37] 2/-0.1/-50/50 10 6 5 × 10 8 -Cu/NG/HfO 2 [38] 4/−4 0.5/0.5 0.5/0.5 10 7 >10 6 2 × 10 5 at 125 • C…”

Adaptive Crystallite Kinetics in Homogenous Bilayer Oxide Memristor for Emulating Diverse Synaptic Plasticity

“…Because the electrode diameter is 50 µm, the switching energy would be 5–7.5 fJ for an individual device if 500 nm technology is adopted. Therefore, our memristor has an advantage in energy consumption because most reported memristors prepared under the technique with line width down to hundreds of nanometers operate on a current level of microampere . Some typical energy consumption data are listed in Table S1 (Supporting Information).…”

Advanced atomic force microscopy-based techniques for nanoscale characterization of switching devices for emerging neuromorphic applications

“…Xu et al ( 2014 ) reported that the switching mechanisms in memristive devices produce conductive filaments (CFs) in the switching layer (SL). CF-forming mechanisms such as filaments form along with oxygen vacancies (Ju et al 2017 ) and electrode diffusion (Xu et al 2014 ). Other theories have recently been published to elucidate the switching behavior such as field-induced electron hopping transport (Ielmini and Zhang 2007 ) and metastable metavalent bond formation (Noé et al 2020 ; Raty and Noe 2020 ).…”