Investigation of Switching Phenomenon in Metal-Tantalum Oxide Interface

2015 ◽  
Vol 15 (10) ◽  
pp. 7564-7568 ◽  
Author(s):  
Abbas Yawar ◽  
Mi Ra Park ◽  
Quanli Hu ◽  
Woo Jin Song ◽  
Tae-Sik Yoon ◽  
...  

To investigate the nature of the switching phenomenon at the metal-tantalum oxide interface, we fabricated a memory device in which a tantalum oxide amorphous layer acted as a switching medium. Different metals were deposited on top of the tantalum oxide layer to ensure that they will react with some of the oxygen contents already present in the amorphous layer of the tantalum oxide. This will cause the formation of metal oxide (MOx) at the interface. Two devices with Ti and Cu as the top electrodes were fabricated for this purpose. Both devices showed bipolar switching characteristics. The SET and RESET voltages for the Ti top electrode device were ∼+1.7 V and ∼−2 V, respectively, whereas the SET and RESET voltages for the Cu top electrode device were ∼+0.9 V and ∼−0.9 V, respectively. In the high-resistance state (HRS) conduction, the mechanisms involved in the devices with Ti and Cu top electrodes were space-charge limited conduction (SCLC) and ohmic, respectively. On the other hand, in the low-resistance state (LRS), the Ti top electrode device undergoes SCLC at a high voltage and ohmic conduction at a low voltage, and the Cu top electrode again undergoes ohmic conduction. From the consecutive sweep cycles, it was observed that the SET voltage gradually decreased with the sweeps for the Cu top electrode device, whereas for the Ti top electrode device, the set voltage did not vary with the sweeps.

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1199
Author(s):  
Hojeong Ryu ◽  
Sungjun Kim

This study presents conductance modulation in a Pt/TiO2/HfAlOx/TiN resistive memory device in the compliance region for neuromorphic system applications. First, the chemical and material characteristics of the atomic-layer-deposited films were verified by X-ray photoelectron spectroscopy depth profiling. The low-resistance state was effectively controlled by the compliance current, and the high-resistance state was adjusted by the reset stop voltage. Stable endurance and retention in bipolar resistive switching were achieved. When a compliance current of 1 mA was imposed, only gradual switching was observed in the reset process. Self-compliance was used after an abrupt set transition to achieve a gradual set process. Finally, 10 cycles of long-term potentiation and depression were obtained in the compliance current region for neuromorphic system applications.


2020 ◽  
Vol 20 (8) ◽  
pp. 4740-4745
Author(s):  
Shin-Yi Min ◽  
Won-Ju Cho

In this study, we fabricated a resistive random access memory (ReRAM) of metal-insulator-metal structures using a hydrogen silsesquioxane (HSQ) film that was deposited by a low-cost solution process as a resistance switching (RS) layer. For post-deposition annealing (PDA) to improve the switching performance of HSQ-based ReRAMs, we applied high energy-efficient microwave irradiation (MWI). For comparison, ReRAMs with an as-deposited HSQ layer or a conventional thermally annealed (CTA) HSQ layer were also prepared. The RS characteristics, molecular structure modification of the HSQ layer, and reliability of the MWI-treated ReRAM were evaluated and compared with the as-deposited or CTA-treated devices. Typical bipolar RS (BRS) behavior was observed in all the fabricated HSQ-based ReRAM devices. In the low-voltage region of the high-resistance state (HRS) as well as the low-resistance state, current flows through the HSQ layer by an ohmic conduction mechanism. However, as the applied voltage increases in HRS, the current slope increases nonlinearly and follows the Poole–Frenkel conduction mechanism. The RS characteristics of the HSQ layer depend on the molecular structure, and when the PDA changes from a cage-like structure to a cross-linked network, memory characteristics are improved. In particular, the MWI-treated HSQ ReRAM has the largest memory window at the smallest operating power and demonstrated a stable endurance during the DC cycling test over 500 times and reliable retention at room (25 °C) and high (85 °C) temperatures for 104 seconds.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7535
Author(s):  
Ghulam Dastgeer ◽  
Amir Muhammad Afzal ◽  
Jamal Aziz ◽  
Sajjad Hussain ◽  
Syed Hassan Abbas Jaffery ◽  
...  

Two-terminal, non-volatile memory devices are the fundamental building blocks of memory-storage devices to store the required information, but their lack of flexibility limits their potential for biological applications. After the discovery of two-dimensional (2D) materials, flexible memory devices are easy to build, because of their flexible nature. Here, we report on our flexible resistive-switching devices, composed of a bilayer tin-oxide/tungsten-ditelluride (SnO2/WTe2) heterostructure sandwiched between Ag (top) and Au (bottom) metal electrodes over a flexible PET substrate. The Ag/SnO2/WTe2/Au flexible devices exhibited highly stable resistive switching along with an excellent retention time. Triggering the device from a high-resistance state (HRS) to a low-resistance state (LRS) is attributed to Ag filament formation because of its diffusion. The conductive filament begins its development from the anode to the cathode, contrary to the formal electrochemical metallization theory. The bilayer structure of SnO2/WTe2 improved the endurance of the devices and reduced the switching voltage by up to 0.2 V compared to the single SnO2 stacked devices. These flexible and low-power-consumption features may lead to the construction of a wearable memory device for data-storage purposes.


Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 947 ◽  
Author(s):  
Seunghyun Ha ◽  
Hyunjae Lee ◽  
Won-Yong Lee ◽  
Bongho Jang ◽  
Hyuk-Jun Kwon ◽  
...  

We investigate the annealing environment effect on ZrO2-based resistive random-access memory (RRAM) devices. Fabricated devices exhibited conventional bipolar-switching memory properties. In particular, the vacuum-annealed ZrO2 films exhibited larger crystallinity and grain size, denser film, and a relatively small quantity of oxygen vacancies compared with the films annealed in air and N2. These led to a decrease in the leakage current and an increase in the resistance ratio of the high-resistance state (HRS)/low-resistance state (LRS) and successfully improved non-volatile memory properties, such as endurance and retention characteristics. The HRS and LRS values were found to last for 104 s without any significant degradation.


2007 ◽  
Vol 997 ◽  
Author(s):  
Pang Shiu Chen ◽  
Heng-Yuan Lee ◽  
Ching-Chiun Wang ◽  
Ming-Jinn Tsai ◽  
Kou-Chen Liu

AbstractThe materials properties and resistance switching characteristics of hafnium oxide-based binary oxide were investigated for next generation memory device application. A nonstoichometric hafnium oxide (HfOx) film with a mixture structure of monoclinic and tetragonal phase and some metallic Hf-Hf bonds on TiN/Si were prepared by atomic layer chemical vapor deposition (ALCVD). Resistance random access memory devices consisting of Pt/HfOx/TiN/Si with low power operation (< 0.4 mW) and reset current (< 100 mA) were fabricated. The resistance ratio of high resistance state to low resistance state maintains 100∼1000 and after 1000 cycles of repetitively switching. A 1-nm-thick Al2O3 film in the interface between top electrode and HfOx films, the Pt/Al2O3/HfOx/TiN/Si memory devices were found that soft-error of set and reset process often occurred. Interface states in the anode side play an important role in maintaining a stable resistive switching for HfOx-based memory devices.


2019 ◽  
Vol 213 ◽  
pp. 303-319 ◽  
Author(s):  
Nobuki Inoue ◽  
Hisao Nakamura

We investigated the resistive switching mechanism between the high-resistance state (HRS) and the low-resistance state (LRS) of the GeTe–Sb2Te3 (GST) superlattice.


Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5618
Author(s):  
Lindiomar Borges Avila ◽  
Christian K. Müller ◽  
Dirk Hildebrand ◽  
Fabrício L. Faita ◽  
Bruna F. Baggio ◽  
...  

Prussian blue (PB) layers were electrodeposited for the fabrication of Au/PB/Ag stacks to study the resistive switching effect. The PB layers were characterized by different techniques to prove the homogeneity, composition, and structure. Electrical measurements confirmed the bipolar switching behavior with at least 3 orders of magnitude in current and the effect persisting for the 200 cycles tested. The low resistance state follows the ohmic conduction with an activation energy of 0.2 eV.


2020 ◽  
Vol 10 (10) ◽  
pp. 3506
Author(s):  
Nayan C. Das ◽  
Se-I Oh ◽  
Jarnardhanan R. Rani ◽  
Sung-Min Hong ◽  
Jae-Hyung Jang

Resistive random-access memory (RRAM) devices are fabricated by utilizing silicon oxynitride (SiOxNy) thin film as a resistive switching layer. A SiOxNy layer is deposited on a p+-Si substrate and capped with a top electrode consisting of Au/Ni. The SiOxNy-based memory device demonstrates bipolar multilevel operation. It can switch interchangeably between all resistance states, including direct SET switching from a high-resistance state (HRS) to an intermediate-resistance state (IRS) or low-resistance state (LRS), direct RESET switching process from LRS to IRS or HRS, and SET/RESET switching from IRS to LRS or HRS by controlling the magnitude of the applied write voltage signal. The device also shows electroforming-free ternary nonvolatile resistive switching characteristics having RHRS/RIRS > 10, RIRS/RLRS > 5, RHRS/RLRS > 103, and retention over 1.8 × 104 s. The resistive switching mechanism in the devices is found to be combinatory processes of hopping conduction by charge trapping/detrapping in the bulk SiOxNy layer and filamentary switching mode at the interface between the SiOxNy and Ni layers.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Chih-Yi Liu ◽  
Yueh-Ying Tsai ◽  
Wen-Tsung Fang ◽  
Hung-Yu Wang

A 20 nm SiOxlayer is deposited using radio-frequency sputtering to form the resistive switching layer of a Cu/SiOx/Pt memory device. The SiOx-based device demonstrates the resistive switching characteristics with an electrochemical reaction. CF4plasma treatment was used to modify the SiOxlayer and incorporate fluorine atoms into theSiOxlayer. The bombardment damage and fluorine incorporation caused the SiOxfilm to form a stack-like structure. This reduced the operating voltage and improved switching dispersion. The fluorine repaired the Cu/SiOxinterface, thus increasing the barrier height of the Cu/SiOxinterface and the resistance of the high resistance state. A statistical analysis of the conducting filament formation was performed in order to evaluate the number of formation/rupture sites. The resistive switching of the CF4-treated sample had higher possibility to use the same filament sites; thus, the CF4-treated sample had stable resistive switching behavior.


2007 ◽  
Vol 124-126 ◽  
pp. 17-20
Author(s):  
Seung Woo Han ◽  
Kyoung Wan Park ◽  
Jung Hyun Sok

Resistance-switching behaviors of the Pr0.7Ca0.3MnO3(PCMO) films based metalinsulator- metal (MIM) devices has been investigated. In this work, resistance change of PCMO films deposited with SRO buffer layers by using RF-magnetron sputtering system investigated at room temperature. The ratio of the resistance change of the PCMO films with SRO buffer layers in the high-resistance state to that in the low-resistance state turned out to be much lager than that of the PCMO films without SRO buffer layers. Moreover, The reproducible property of the fabricated samples were improved. Origin of resistance change is not clear, but PCMO films with SRO buffer layers have the possibility of application for nonvolatile memory device.


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