WOx resistive memory elements for scaled Flash memories

2011 ◽  
Vol 1337 ◽  
Author(s):  
S. Gorji Ghalamestani ◽  
L. Goux ◽  
D.E. Díaz-Droguett ◽  
D. Wouters ◽  
J. G. Lisoni
Keyword(s):  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Time Windows ◽  
Electrical Measurement ◽  
Thin Layers ◽  
Switching Behavior ◽  
Elastic Recoil ◽  
X Ray ◽  
Bipolar Switching ◽  
Switching Characteristics

ABSTRACTWe investigated the resistive switching behavior of WOx films. WOx was obtained from the thermal oxidation of W thin layers. The parameters under investigation were the influence of the temperature (450-500 °C) and time (30-220 s) used to obtain the WOx on the resistive switching characteristics of Si\W\WOx\Metal_electrode ReRAM cells. The metal top electrodes (TE) tested were Pt, Ni, Cu and Au. The elemental composition and microstructure of the samples were characterized by means of elastic recoil detection analysis (ERD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray reflectivity (XRR).Electrical measurement of the WOx-based memory elements revealed bipolar and unipolar switching and this depended upon the oxidation conditions and TE selected. Indeed, switching events were observed in WOx samples obtained either at 450 °C or 500 °C in time windows of 180-200 s and 30-60 s, respectively. Pt and Au TE promoted bipolar switching while unipolar behavior was observed with Ni TE only; no switching events were observed with Cu TE. Good switching characteristics seems not related to the overall thickness, crystallinity and composition of the oxide, but on the W6+/W5+ ratio present on the WOx surface, surface in contact with the TE material. Interestingly, W6+/W5+ ratio can be tuned through the oxidation conditions, showing a path for optimizing the properties of the WOx-based ReRAM cells.

Resistive switching characteristics of all-solution-based Ag/TiO2/Mo-doped In2O3devices for non-volatile memory applications

2016 ◽  
Vol 4 (46) ◽  
pp. 10967-10972 ◽  
Author(s):  
Sujaya Kumar Vishwanath ◽  
Jihoon Kim
Keyword(s):  
Resistive Switching ◽  
Retention Time ◽  
Elevated Temperatures ◽  
Switching Behavior ◽  
Memory Devices ◽  
Bipolar Switching ◽  
Non Volatile Memory ◽  
Volatile Memory ◽  
Switching Characteristics ◽  
Memory Applications

The all-solution-based memory devices demonstrated excellent bipolar switching behavior with a high resistive switching ratio of 103, excellent endurance of more than 1000 cycles, stable retention time greater than 104s at elevated temperatures, and fast programming speed of 250 ns.

scholarly journals Resistive Switching Characteristics of Li-Doped ZnO Thin Films Based on Magnetron Sputtering

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1282 ◽  
Author(s):  
Zhao ◽  
Li ◽  
Ai ◽  
Wen
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Lattice Structure ◽  
Zno Thin Films ◽  
Bipolar Resistive Switching ◽  
X Ray ◽  
Doped Zno ◽  
Switching Characteristics

A kind of devices Pt/Ag/ZnO:Li/Pt/Ti with high resistive switching behaviors were prepared on a SiO2/Si substrate by using magnetron sputtering method and mask technology, composed of a bottom electrode (BE) of Pt/Ti, a resistive switching layer of ZnO:Li thin film and a top electrode (TE) of Pt/Ag. To determine the crystal lattice structure and the Li-doped concentration in the resulted ZnO thin films, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) tests were carried out. Resistive switching behaviors of the devices with different thicknesses of Li-doped ZnO thin films were studied at different set and reset voltages based on analog and digital resistive switching characteristics. At room temperature, the fabricated devices represent stable bipolar resistive switching behaviors with a low set voltage, a high switching current ratio and a long retention up to 104 s. In addition, the device can sustain an excellent endurance more than 103 cycles at an applied pulse voltage. The mechanism on how the thicknesses of the Li-doped ZnO thin films affect the resistive switching behaviors was investigated by installing conduction mechanism models. This study provides a new strategy for fabricating the resistive random access memory (ReRAM) device used in practice.

scholarly journals Switching Characteristics and Mechanism Using Al2O3 Interfacial Layer in Al/Cu/GdOx/Al2O3/TiN Memristor

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1466
Author(s):  
Chiao-Fan Chiu ◽  
Sreekanth Ginnaram ◽  
Asim Senapati ◽  
Yi-Pin Chen ◽  
Siddheswar Maikap
Keyword(s):  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Interfacial Layer ◽  
Stable State ◽  
Schematic Model ◽  
Bipolar Resistive Switching ◽  
Al2o3 Layer ◽  
X Ray ◽  
Resistance State ◽  
Switching Characteristics

Resistive switching characteristics by using the Al2O3 interfacial layer in an Al/Cu/GdOx/Al2O3/TiN memristor have been enhanced as compared to the Al/Cu/GdOx/TiN structure owing to the insertion of Al2O3 layer for the first time. Polycrystalline grain, chemical composition, and surface roughness of defective GdOx film have been investigated by transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and atomic force microscopy (AFM). For bipolar resistive switching (BRS) characteristics, the conduction mechanism of high resistance state (HRS) is a space-charge limited current for the Al/Cu/GdOx/TiN device while the Al/Cu/GdOx/Al2O3/TiN device shows Schottky emission. However, both devices show Ohmic at a low resistance state (LRS). After the device has been SET, the Cu filament evidences by both TEM and elemental mapping. Oxygen-rich at the Cu/GdOx interface and Al2O3 layer are confirmed by energy dispersive X-ray spectroscopy (EDS) line profile. The Al/Cu/GdOx/Al2O3/TiN memristor has lower RESET current, higher speed operation of 100 ns, long read pulse endurance of >109 cycles, good data retention, and the memristor with a large resistance ratio of >105 is operated at a low current of 1.5 µA. The complementary resistive switching (CRS) characteristics of the Al/Cu/GdOx/Al2O3/TiN memristor show also a low current operation as compared to the Al/Cu/GdOx/TiN device (300 µA vs. 3.1 mA). The transport mechanism is the Cu ion migration and it shows Ohmic at low field and hopping at high field regions. A larger hopping distance of 1.82 nm at the Cu/GdOx interface is obtained as compared to a hopping distance of 1.14 nm in the Al2O3 layer owing to a larger Cu filament length at the Cu/GdOx interface than the Al2O3 layer. Similarly, the CRS mechanism is explained by using the schematic model. The CRS characteristics show a stable state with long endurance of >1000 cycles at a pulse width of 1 µs owing to the insertion of Al2O3 interfacial layer in the Al/Cu/GdOx/Al2O3/TiN structure.

scholarly journals Chemical Nature of Electrode and the Switching Response of RF-Sputtered NbOx Films

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2164
Author(s):  
Jamal Aziz ◽  
Honggyun Kim ◽  
Shania Rehman ◽  
Muhammad Farooq Khan ◽  
Deok-kee Kim
Keyword(s):  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Dominant Role ◽  
Interface Layer ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Inert Electrode ◽  
Switching Characteristics ◽  
Different Characteristics

In this study, the dominant role of the top electrode is presented for Nb2O5-based devices to demonstrate either the resistive switching or threshold characteristics. These Nb2O5-based devices may exhibit different characteristics depending on the selection of electrode. The use of the inert electrode (Au) initiates resistive switching characteristics in the Au/Nb2O5/Pt device. Alternatively, threshold characteristics are induced by using reactive electrodes (W and Nb). The X-ray photoelectron spectroscopy analysis confirms the presence of oxide layers of WOy and NbOx at interfaces for W and Nb as top electrodes. However, no interface layer between the top electrode and active layer is detected in X-ray photoelectron spectroscopy for Au as the top electrode. Moreover, the dominant phase is Nb2O5 for Au and NbO2 for W and Nb. The threshold characteristics are attributed to the reduction of Nb2O5 phase to NbO2 due to the interfacial oxide layer formation between the reactive top electrode and Nb2O5. Additionally, reliability tests for both resistive switching and threshold characteristics are also performed to confirm switching stabilities.

scholarly journals The effect of content and thickness of chitosan thin films on resistive switching characteristics

2020 ◽  
Vol 23 (3) ◽  
pp. 632-639
Author(s):  
Phuc Dinh Do ◽  
Tu Uyen Thi Doan ◽  
Tap Duy Tran ◽  
Dung Van Hoang ◽  
Kim Ngoc Pham
Keyword(s):  
Resistive Switching ◽  
Random Access ◽  
Chitosan Film ◽  
Resistive Random Access Memory ◽  
Switching Behavior ◽  
Potential Candidate ◽  
Switching Performance ◽  
Bipolar Switching ◽  
Coating Method ◽  
Switching Characteristics

Introduction: Nowadays, a resistive switching memory using biological, transparent, and environmentally friendly materials is appreciated as the tendency of science and technology, especially in the field of electronic devices. Chitosan (CS), having dominant characteristics such as non-toxic, biocompatible and large capacity, plays as a switching medium in resistive random access memory devices (RRAM). Methods: In our study, CS film was fabricated onto a commercial substrate (FTO) using a simple spin coating method, and the top electrode (Ag) was deposited by a direct-current sputtering technique. Results: The Ag/CS/FTO devices shown the bipolar switching behavior when applying sequence voltage from -1.5 to 2V with the set process in the negative bias and the reset process in the positive bias. The content (0.2, 0.5, and 0.8 wt%) and thickness (100, 300, 500 nm) of chitosan film significantly affect the resistive switching performance. The devices with 0.5 wt%/v concentration and 300 nm-thickness of CS have shown better efficiency than the others with endurance over 100 sweeping cycles and ON/OFF ratio at ca. 2x10 times. Conclusions: It is found that the chitosan material has a large potential candidate for applications in optoelectronic devices.

Titania Based Nano-ionic Memristive Crossbar Arrays: Fabrication and Resistive Switching Characteristics

2019 ◽  
Vol 9 (4) ◽  
pp. 486-493 ◽  
Author(s):  
S. Sahoo ◽  
P. Manoravi ◽  
S.R.S. Prabaharan
Keyword(s):  
Resistive Switching ◽  
Bottom Electrode ◽  
Rf Sputtering ◽  
Hysteresis Curve ◽  
Bipolar Switching ◽  
Post Annealing ◽  
Endurance Tests ◽  
Bilayer Device ◽  
Switching Characteristics ◽  
Pinched Hysteresis

Introduction: Intrinsic resistive switching properties of Pt/TiO2-x/TiO2/Pt crossbar memory array has been examined using the crossbar (4×4) arrays fabricated by using DC/RF sputtering under specific conditions at room temperature. Materials and Methods: The growth of filament is envisaged from bottom electrode (BE) towards the top electrode (TE) by forming conducting nano-filaments across TiO2/TiO2-x bilayer stack. Non-linear pinched hysteresis curve (a signature of memristor) is evident from I-V plot measured using Pt/TiO2-x /TiO2/Pt bilayer device (a single cell amongst the 4×4 array is used). It is found that the observed I-V profile shows two distinguishable regions of switching symmetrically in both SET and RESET cycle. Distinguishable potential profiles are evident from I-V curve; in which region-1 relates to the electroformation prior to switching and region-2 shows the switching to ON state (LRS). It is observed that upon reversing the polarity, bipolar switching (set and reset) is evident from the facile symmetric pinched hysteresis profile. Obtaining such a facile switching is attributed to the desired composition of Titania layers i.e. the rutile TiO2 (stoichiometric) as the first layer obtained via controlled post annealing (650oC/1h) process onto which TiO2-x (anatase) is formed (350oC/1h). Results: These controlled processes adapted during the fabrication step help manipulate the desired potential barrier between metal (Pt) and TiO2 interface. Interestingly, this controlled process variation is found to be crucial for measuring the switching characteristics expected in Titania based memristor. In order to ensure the formation of rutile and anatase phases, XPS, XRD and HRSEM analyses have been carried out. Conclusion: Finally, the reliability of bilayer memristive structure is investigated by monitoring the retention (104 s) and endurance tests which ensured the reproducibility over 10,000 cycles.

scholarly journals High-Performance Resistive Switching in Solution-Derived IGZO:N Memristors by Microwave-Assisted Nitridation

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1081
Author(s):  
Shin-Yi Min ◽  
Won-Ju Cho
Keyword(s):  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Electric Pulse ◽  
Chemical Species ◽  
Optical Absorption Coefficient ◽  
Microwave Assisted ◽  
Synthesis Strategy ◽  
Metal Insulator Metal ◽  
Switching Characteristics

In this study, we implemented a high-performance two-terminal memristor device with a metal/insulator/metal (MIM) structure using a solution-derived In-Ga-Zn-Oxide (IGZO)-based nanocomposite as a resistive switching (RS) layer. In order to secure stable memristive switching characteristics, IGZO:N nanocomposites were synthesized through the microwave-assisted nitridation of solution-derived IGZO thin films, and the resulting improvement in synaptic characteristics was systematically evaluated. The microwave-assisted nitridation of solution-derived IGZO films was clearly demonstrated by chemical etching, optical absorption coefficient analysis, and X-ray photoelectron spectroscopy. Two types of memristor devices were prepared using an IGZO or an IGZO:N nanocomposite film as an RS layer. As a result, the IGZO:N memristors showed excellent endurance and resistance distribution in the 103 repeated cycling tests, while the IGZO memristors showed poor characteristics. Furthermore, in terms of electrical synaptic operation, the IGZO:N memristors possessed a highly stable nonvolatile multi-level resistance controllability and yielded better electric pulse-induced conductance modulation in 5 × 102 stimulation pulses. These findings demonstrate that the microwave annealing process is an effective synthesis strategy for the incorporation of chemical species into the nanocomposite framework, and that the microwave-assisted nitridation improves the memristive switching characteristics in the oxide-based RS layer.

scholarly journals Effects of the thickness on resistive switching characteristics of CrOx thin films

2016 ◽  
Vol 19 (2) ◽  
pp. 92-100
Author(s):  
Ngoc Kim Pham ◽  
Thang Bach Phan ◽  
Vinh Cao Tran
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Resistive Switching ◽  
High Reliability ◽  
Switching Behavior ◽  
Ftir Analysis ◽  
Resistive Switching Behavior ◽  
Bipolar Resistive Switching ◽  
Structure Surface ◽  
Switching Characteristics

In this study, we have investigated influences of the thickness on the structure, surface morphology and resistive switching characteristics of CrOx thin films prepared by using DC reactive sputtering technique. The Raman and FTIR analysis revealed that multiphases including Cr2O3, CrO2, Cr8O21... phases coexist in the microstructure of CrOx film. It is noticed that the amount of stoichiometric Cr2O3 phase increased significantly as well as the surface morphology were more visible with less voids and more densed particles with larger thickness films. The Ag/CrOx/FTO devices exhibited bipolar resistive switching behavior and high reliability. The resistive switching ratio has decreased slightly with the thickness increments and was best achieved at CrOx – 100 nm devices.

scholarly journals Resistive switching in a LaMnO3 + δ/TiN memory cell investigated by operando hard X-ray photoelectron spectroscopy

2019 ◽  
Vol 126 (22) ◽  
pp. 225302 ◽  
Author(s):  
Benjamin Meunier ◽  
Eugénie Martinez ◽  
Raquel Rodriguez-Lamas ◽  
Dolors Pla ◽  
Mònica Burriel ◽  
...  
Keyword(s):  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Memory Cell ◽  
X Ray

scholarly journals Synthesis and characterization of Cr–B–N coatings deposited by reactive arc evaporation

2008 ◽  
Vol 23 (11) ◽  
pp. 3048-3055 ◽  
Author(s):  
K. Polychronopoulou ◽  
J. Neidhardt ◽  
C. Rebholz ◽  
M.A. Baker ◽  
M. O’Sullivan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Partial Pressure ◽  
Photoelectron Spectroscopy ◽  
Columnar Structure ◽  
Elastic Recoil ◽  
Cross Sectional ◽  
X Ray ◽  
Elastic Recoil Detection ◽  
Selected Area Electron Diffraction ◽  
Arc Evaporation

Nanocomposite Cr–B–N coatings were deposited from CrB0.2 compound targets by reactive arc evaporation using an Ar/N2 discharge at 500 °C and −20 V substrate bias. Elastic recoil detection (ERDA), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and selected-area electron diffraction (SAED) were used to study the effect of the N2 partial pressure on composition and microstructure of the coatings. Cross-sectional scanning electron microscopy (SEM) showed that the coating morphology changes from a glassy to a columnar structure with increasing N2 partial pressure, which coincides with the transition from an amorphous to a crystalline growth mode. The saturation of N content in the coating confirms the formation of a thermodynamically stable CrN–BN dual-phase structure at higher N2 fractions, exhibiting a maximum in hardness of approximately 29 GPa.

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