Woven resistive switching using aluminum and carbon fibers for memory devices

이미정 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0

Recently, wearable electronics such as google glasses and smart watch were launched in the market to recieve increasing attention as new generation electronic devices. In the near future, wearable electronics will be literally‘wearable’as smart clothing, smart fabrics and electronic textile form. Some researchers reported electronic textiles suitable for integration of devices using metal wire or conductive yarn. In this paper, we fabricated resistive switching memory devices using one dimensional conductive yarn for flexible electronic textile based on solution processes. Conducting fibers costructing texture were fabricated using and Al coated on carbon yarn, which act as an electrode. Carbon yarns, core of fiberes, were exposed to catalyst and immersed in alumi num precursor solution. Then Polymethylmethacrylate (PMMA) is coated on the conductive aluminium yarn using dip coating method to prevent a short between condcuting fibers and to act as a resistive switching layer. Carbon yarn was placed on the PMMA/Al coated yarn perpendiculary to form another electrode. We observed resistive switching characteristics of Carbon/PMMA/Al/Carbon fiber cross structure. Without forming process, the devices show bipolar resistive switching. The virgin device is in low resistance state. When positive bias is applied, the device switches to high resistance state. In this manner, ‘write’ and ‘erase’ operation was possible switch the resistance of the junction devices of two fibers. Interesting thing is the switching of resistivity worked even more stably without insulating PMMA layer. The device performed with switching more than 100 cycles endurance and retention properties up to 10000s only with two conducting fibers crossed. According to EDS and SEM results, we contemplate that resistive switching occurs in the Al layer which containes significant oxygen level to show native oxide layer of aluminum involved in the process. Furthermore, XPS analysis showed that new phase could be the main reason for the unique properties of resistive switching with two conducting layers which was not observed in conventional metal/metal structure. Switching mechanism with aluminum/carbon structure could be explained in this work with various analysis at the interface and by exploring different configuration of the device structure. Although the study is in early stage, this result shows the possibility of simple approach towards woven electronics using only flexible conductive yarns working with novel mechanism.

Resistive Switching Memory Based on Bioinspired Natural Solid Polymer Electrolytes

Raeis Hosseini, Niloufar,Lee, Jang-Sik American Chemical Society 2015 ACS NANO Vol.9 No.1

<P>A solution-processed, chitosan-based resistive-switching memory device is demonstrated with Pt/Ag-doped chitosan/Ag structure. The memory device shows reproducible and reliable bipolar resistive switching characteristics. A memory device based on natural organic material is a promising device toward the next generation of nonvolatile nanoelectronics. The memory device based on chitosan as a natural solid polymer electrolyte can be switched reproducibly between high and low resistance states. In addition, the data retention measurement confirmed the reliability of the chitosan-based nonvolatile memory device. The transparent Ag-embedded chitosan film showed an acceptable and comparable resistive switching behavior on the flexible plastic substrate as well. A cost-effective, environmentally benign memory device using chitosan satisfies the functional requirements of nonvolatile memory operations.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-1/nn5055909/production/images/medium/nn-2014-055909_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn5055909'>ACS Electronic Supporting Info</A></P>

Mechanism analysis of switching direction transformation in an Er2O3 based RRAM device

Shuangsuo Mao,Guangdong Zhou,Bai Sun,Hosameldeen Elshekh,Xiaohua Zhang,Xiaohua Zhang,Feng Yang,Yong Zhao 한국물리학회 2019 Current Applied Physics Vol.19 No.12

The resistive random access memory (RRAM) based on resistive switching effect has considered to be the most advanced next generation memory, in which the switching direction determines the order of reading-writing. In this work, the rare-earth metal Er2O3 was used as functional layer, and Ag and indium-tin-oxide (ITO) are selected as top and bottom electrode to fabricate resistive switching device. Further, it is observed that the switching direction and memory window of resistive switching device can be regulated by exchanging top and bottom electrode. Moreover, the complementary switching memory behavior in Ag/Er2O3/ITO/Er2O3/Ag structure was also observed. Through mechanism analysis, it is expected that the barrier changes and metal-ions oxidation-reduction should be responsible for the conversion of switching direction and regulation of memory window. This work opens up a way to the development of next generation new concept memory.

A larger nonvolatile bipolar resistive switching memory behaviour fabricated using eggshells

Guangdong Zhou,Bai Sun,Ankun Zhou,Bo Wu,Haishen Huang 한국물리학회 2017 Current Applied Physics Vol.17 No.2

Resistive random access memory (RRAM) devices have emerged as promising candidates for near future nonvolatile information storage. Eggshells, a food waste, have not been focused and recycled sustainably today. Eggshell-based devices have shown a large resistive-switching(RS) memory behaviors with favorable resistance ratio of ~103, larger memory window of ~3.5 V, and high endurance and retention performance. Redox-based Ag filament models involving the formation and rupture of the metallic conduction filaments between top and bottom electrodes are proposed to interpret the large nonvolatile bipolar RS memory behaviors. This discovery provides for the possibility of an environmentally friendly, low-cost and sustainable material application in the next-generation nonvolatile date storage device

Dual Functions of V/SiO _<i>x</i> /AlO _<i>y</i> /p ⁺⁺ Si Device as Selector and Memory

Kim, Sungjun,Lin, Chih-Yang,Kim, Min-Hwi,Kim, Tae-Hyeon,Kim, Hyungjin,Chen, Ying-Chen,Chang, Yao-Feng,Park, Byung-Gook Springer US 2018 NANOSCALE RESEARCH LETTERS Vol.13 No.1

<P>This letter presents dual functions including selector and memory switching in a V/SiO<SUB><I>x</I></SUB>/AlO<SUB><I>y</I></SUB>/p<SUP>++</SUP>Si resistive memory device by simply controlling compliance current limit (CCL). Unidirectional threshold switching is observed after a positive forming with low CCL of 1 μA. The shifts to the V-electrode side of the oxygen form the VO<SUB><I>x</I></SUB> layer, where the threshold switching can be explained by the metal-insulation-transition phenomenon. For higher CCL (30 μA) applied to the device, a bipolar memory switching is obtained, which is attributed to formation and rupture of the conducting filament in SiO<SUB><I>y</I></SUB> layer. 1.5-nm-thick AlO<SUB><I>y</I></SUB> layer with high thermal conductivity plays an important role in lowering the off-current for memory and threshold switching. Through the temperature dependence, high-energy barrier (0.463 eV) in the LRS is confirmed, which can cause nonlinearity in a low-resistance state. The smaller the CCL, the higher the nonlinearity, which provides a larger array size in the cross-point array. The coexistence of memory and threshold switching in accordance with the CCL provides the flexibility to control the device for its intended use.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (10.1186/s11671-018-2660-9) contains supplementary material, which is available to authorized users.</P>

Resistive switching memory based on organic/inorganic hybrid perovskite materials

Liu, Y.,Li, F.,Chen, Z.,Guo, T.,Wu, C.,Kim, T.W. Pergamon Press [etc.] 2016 Vacuum Vol.130 No.-

<P>In this work, a resistance switching memory based on organic/inorganic hybrid perovskites (OIHPs) was fabricated. The CH3NH3PbI3 perovskite was grown on polymethyl methacrylate (PMMA) as the resistance switching layer by using a two-step spin-coating procedure. The conduction mechanisms of indium-tin oxide (ITO)/PMMA/CH3NH3PbI3/PMMA/Ag device were investigated in terms of current voltage characteristics. The memory device is reprogrammable and the ON/OFF ratio reaches as high as 10(3). Endurance cycle of the as-fabricated memory device was also carried out. The results indicate the promising electronic application of OIHPs in resistance switching memories. (C) 2016 Elsevier Ltd. All rights reserved.</P>

One-Dimensional TiO₂@Ag Nanoarchitectures with Interface-Mediated Implementation of Resistance-Switching Behavior in Polymer Nanocomposites

Oh, Kiwon,Jeon, Woojin,Lee, Sang-Soo American Chemical Society 2012 ACS APPLIED MATERIALS & INTERFACES Vol.4 No.11

<P>A nanocomposite capable of showing a resistance-switching behavior is prepared using novel resistance-switchable fillers embedded in a polymer matrix. The filler in this study employs a conformal passivation layer of highly crystalline TiO<SUB>2</SUB> on surfaces of conductive Ag nanowires to effectively gate electron flows delivered through the conductive core, resulting in an excellent resistance-switching performance. A nanocomposite prepared by controlled mixing of the resistance-switchable nanowires with a polymer matrix successfully exhibited a resistance-switching behavior of highly enhanced reliability and a resistance on/off ratio, along with flexibility due to the presence of nanowires of a tiny amount. The advantages of our approach include a simple and low-cost fabrication procedure along with sustainable performances suitable for a resistance-switching random-access-memory application.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2012/aamick.2012.4.issue-11/am301362f/production/images/medium/am-2012-01362f_0005.gif'></P>

Thickness-dependent Resistance Switching in Cr-doped SrTiO3

김태광,두혜원,김민창,서순애,황인록,김연수,Jihoon Jeon,Sangik Lee,박배호 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.5

Thickness dependent bipolar resistance switching behavior was investigated on epitaxially grown Cr-doped SrTiO<SUB>3</SUB> (Cr-STO). All the pristine devices of different thickness show polarity independent symmetric current-voltage characteristic and the same space charge limited conduction mechanism. However, after a forming process the resultant conduction and switching phenomena are significantly disparate depending on the thickness of Cr-STO. The forming process itself is highly influenced by resistance values of each pristine device. Based on our results, we suggest that the resistance switching mechanism in Cr-STO is dependent not only on the insulating material composition or contact metal as previously reported but also on the initial resistance level determined by geometry and the quality of the insulating material. Bipolar resistance switching behavior in oxide material of different thickness exhibit mixed bulk and interface switching. This indicates that efforts in resistance based memory research should be focused on scalability or process method to control a given oxide material in addition to material type and device structure.

Characteristics of Resistive Switching in ZnO/SiOx Multi-Layers for Transparent Nonvolatile Memory Devices

Kyongmin Kim,Eunkyeom Kim,Youngill Kim,Jung Hyun Sok,Kyoungwan Park 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.12

Bipolar resistive switching in ZnO/SiOx bi-layer and ZnO/SiOx/ZnO tri-layer structures was investigated for nonvolatile memory applications. ZnO thin films were grown using the radiofrequency magnetron sputtering technique at room temperature. SiOx films were grown using plasma-enhanced chemical-vapor deposition at 200 C. Multiple high-resistance states were observed during the set process. The high/low resistance state ratio was 10 during 100 on/off cycles. The tri-layer memory device exhibited better endurance properties than the bi-layer device. Because an asymmetric conducting filament has a weak point for charge conduction at the oxide interfaces, we attributed the good endurance property to the reproducible formation/rupture of “micro”-conducting filaments. Moreover, the dynamics of the oxygen ions in the SiOx layer plays an important role in resistive switching.

Gradual switching and self-rectifying characteristics of Cu/<i>α</i>-IGZO/<i>p</i> ⁺-Si RRAM for synaptic device application

Bang, Suhyun,Kim, Min-Hwi,Kim, Tae-Hyeon,Lee, Dong Keun,Kim, Sungjun,Cho, Seongjae,Park, Byung-Gook Elsevier 2018 Solid-State Electronics Vol.150 No.-

<P><B>Abstract</B></P> <P>In this work, we investigated the gradual switching and self-rectifying characteristics of Cu/<I>α</I>-IGZO/<I>p</I> <SUP>+</SUP>-Si resistive-switching random-access memory (RRAM) device. We fabricated the RRAM cells with Cu as the top electrode (TE) and heavily doped <I>p</I>-type silicon as the bottom electrode (BE), and amorphous indium gallium zinc oxide (<I>α</I>-IGZO) film as the switching layer. In particular, we developed a bilayer IGZO film consisting of an oxygen-deficient layer and an oxygen-rich one by controlling the oxygen concentrations in the respective switching layers in the expectation of gradual switching owing to an oxygen vacancy reservoir. Fabricated RRAM cells successfully showed the typical hysteretic <I>I</I>–<I>V</I> curves including SET and RESET operations in the DC sweep mode. Furthermore, gradual switching and self-rectifying performances were observed. These characteristics are suitable to applications for synaptic devices toward the advanced neuromorphic systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> RRAM using Cu/<I>α</I>-IGZO/<I>p</I> <SUP>+</SUP>-Si stack was fabricated and measured. </LI> <LI> Proposed device shows the self-rectifying phenomenon. </LI> <LI> Proposed device shows the gradual conductance change under identical voltage pulses. </LI> </UL> </P>