Bipolar resistive switching characteristics of samarium oxide solid electrolyte thin films for non-volatile memory applications

2019 ◽  
Vol 12 (03) ◽  
pp. 1950023
Author(s):  
Mei Ji ◽  
Yangjiang Wu ◽  
Zhengzhong Zhang ◽  
Ya Wang ◽  
Hao Liu

In this paper, we report the bipolar resistive switching behaviors in Ag/Sm2O3/Pt structures where the Sm2O3 thin films act as solid electrolyte layer of electrochemical metallization memory (ECM) devices. The memory devices show reproducible and stable bipolar resistive switching over 1000 cycles with a resistance ratio (high-resistance state to low-resistance state) of over 4 orders of magnitude and stable retention for over 104[Formula: see text]s at room temperature. Moreover, the benefits of high yield and multilevel storage possibility make the device promising in the next generation non-volatile memory application.

2017 ◽  
Vol 30 (4) ◽  
pp. 65-68
Author(s):  
Eric Hernandez Rodriguez ◽  
Alfredo Marquez Herrera ◽  
Miguel Melendez Lira ◽  
Enrique Valaguez Velazquez ◽  
Martin Zapata Torres

We investigated the electric-field-induced resistance-switching behavior of metal-insulator-metal (MIM) cells based on TiO2 thin films fabricated by the reactive RF-sputtering technique. MIM cells were constructed by sandwiched TiO2 thin films between a pair of electrodes; Ti thin films were employed to form an ohmic bottom contact and NiCr thin films were employed to form Schottky top electrodes obtaining Ti/TiO2/NiCr MIM cells. Schottky barrier height for the TiO2/NiCr junction was determined according to the thermionic emission model by using the Cheung´s functions. SEM and Raman analysis of the TiO2 thin films were carried out to ensure the quality of the films. Current-Voltage (I-V) sweeps obtained at room temperature by the application of dc bias showed a bipolar resistive switching behavior on the cells. Both low resistance state (ON state) and high resistance state (OFF state), of Ti/TiO2/NiCr cells are stable and reproducible during a successive resistive switching. The resistance ratio of ON and OFF state is over 103 and the retention properties of both states are very stable after 105 s with a voltage test of 0.1 V.


MRS Advances ◽  
2019 ◽  
Vol 4 (48) ◽  
pp. 2601-2607
Author(s):  
Toshiki Miyatani ◽  
Yusuke Nishi ◽  
Tsunenobu Kimoto

ABSTRACTImpacts of a forming process on bipolar resistive switching (RS) characteristics in Pt/TaOx/Ta2O5/Pt cells were investigated. We found that the forming resulted in a transition from an initial state to a particular high resistance state (HRS) in most of the Pt/TaOx/Ta2O5/Pt cells. Evaluation of electrical characteristics after the transition to the particular HRS revealed that two modes of bipolar RS with the conventional polarity based on valence change mechanism and with the opposite polarity could be selectively obtained by adjusting the magnitude of the applied voltage. Moreover, the cell resistance decreased gradually during set processes in the bipolar RS with the opposite polarity.


2011 ◽  
Vol 687 ◽  
pp. 106-111
Author(s):  
Chih Yi Liu ◽  
Yu Chen Li ◽  
Chun Hung Lai ◽  
Shih Kun Liu

CuxO and SiO2thin films were deposited using a radio-frequency magnetron sputter on Pt/Ti/SiO2/Si substrates to form SiO2/CuxO/Pt and CuxO/Pt structures. The current-voltage characteristics were measured by DC voltage sweeping using a tungsten (W) probe. The two structures needed a large voltage to initiate the first resistive switching; this sweep was called the forming process. Afterwards, the resistances of the two structures could be switched reversibly between the low-resistance-state (LRS) and high-resistance-state (HRS) by applying a DC voltage. The conduction mechanisms of the LRS and the HRS were dominated by Ohmic conduction. Structures with non-destructive readout characteristics and long retention time were suitable for use in non-volatile memory. The difference between resistive switching in W-probe/SiO2/CuxO/Pt and W-probe/CuxO/Pt structures was investigated. The additional SiO2layer decreased the switching voltages and currents; this should be due to the presence of pinholes within the SiO2layer. The influence of SiO2thickness on the resistive switching characteristics was also investigated. The switching voltages and currents, except the forming voltage, decreased as the thickness of SiO2decreased. The conducting filament model with a thermochemical reaction was suggested to best explain the resistive switching behavior that was observed.


Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 318
Author(s):  
Lin ◽  
Wu ◽  
Chen

: In this work, the resistive switching characteristics of resistive random access memories (RRAMs) containing Sm2O3 and V2O5 films were investigated. All the RRAM structures made in this work showed stable resistive switching behavior. The High-Resistance State and Low-Resistance State of Resistive memory (RHRS/RLRS) ratio of the RRAM device containing a V2O5/Sm2O3 bilayer is one order of magnitude higher than that of the devices containing a single layer of V2O5 or Sm2O3. We also found that the stacking sequence of the Sm2O3 and V2O5 films in the bilayer structure can affect the switching features of the RRAM, causing them to exhibit both bipolar resistive switching (BRS) behavior and self-compliance behavior. The current conduction mechanisms of RRAM devices with different film structures were also discussed.


Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1124 ◽  
Author(s):  
Chao-Feng Liu ◽  
Xin-Gui Tang ◽  
Lun-Quan Wang ◽  
Hui Tang ◽  
Yan-Ping Jiang ◽  
...  

The resistive switching (RS) characteristics of flexible films deposited on mica substrates have rarely been reported upon, especially flexible HfO2 films. A novel flexible Au/HfO2/Pt/mica resistive random access memory device was prepared by a sol-gel process, and a Au/HfO2/Pt/Ti/SiO2/Si (100) device was also prepared for comparison. The HfO2 thin films were grown into the monoclinic phase by the proper annealing process at 700 °C, demonstrated by grazing-incidence X-ray diffraction patterns. The ratio of high/low resistance (off/on) reached 1000 and 50 for the two devices, respectively, being relatively stable for the former but not for the latter. The great difference in ratios for the two devices may have been caused by different concentrations of the oxygen defect obtained by the X-ray photoelectron spectroscopy spectra indicating composition and chemical state of the HfO2 thin films. The conduction mechanism was dominated by Ohm’s law in the low resistance state, while in high resistance state, Ohmic conduction, space charge limited conduction (SCLC), and trap-filled SCLC conducted together.


2011 ◽  
Vol 687 ◽  
pp. 167-173 ◽  
Author(s):  
Chih Yi Liu ◽  
Po Wei Sung ◽  
Chun Hung Lai ◽  
Hung Yu Wang

SiO2thin films were fabricated as resistive layers of Cu/SiO2/Pt devices to investigate resistive switching properties. A thermal annealing was performed to allow for the diffusion of Cu ions into the SiO2thin films, leading to the formation of Cu-doped SiO2layers. Occurrence probabilities of the resistive switching and initial resistance-states of the devices were influenced by SiO2thickness, which was dependent on the Cu diffusion status within the SiO2layer. The resistive switching behaviors were characterized by the voltage sweeping mode and the current sweeping mode. The current sweeping mode provided a desired compliance current to well control the resistive switching from the high resistance-state to the low resistance-state (SET). Therefore, the large RESET (from the low resistance-state to the high resistance-state) current was not inherent in the device, due to poor control of the compliance current by the voltage sweeping mode. The current sweeping mode is a simple method to characterize the RESET current.


Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 440
Author(s):  
Hojeong Ryu ◽  
Sungjun Kim

In this work, resistive switching and synaptic behaviors of a TiO2/Al2O3 bilayer device were studied. The deposition of Pt/Ti/TiO2/Al2O3/TiN stack was confirmed by transmission electron microscopy (TEM) and energy X-ray dispersive spectroscopy (EDS). The initial state before the forming process followed Fowler-Nordheim (FN) tunneling. A strong electric field was applied to Al2O3 with a large energy bandgap for FN tunneling, which was confirmed by the I-V fitting process. Bipolar resistive switching was conducted by the set process in a positive bias and the reset process in a negative bias. High-resistance state (HRS) followed the trap-assisted tunneling (TAT) model while low-resistance state (LRS) followed the Ohmic conduction model. Set and reset operations were verified by pulse. Moreover, potentiation and depression in the biological synapse were verified by repetitive set pulses and reset pulses. Finally, the device showed good pattern recognition accuracy (~88.8%) for a Modified National Institute of Standards and Technology (MNIST) handwritten digit database in a single layer neural network including the conductance update of the device.


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