Ferroelectric capacitors hold great promise for non-volatile memory applications.However,the challenge lies in fabricating resistive switching devices with a high on/off ratio,excellent non-volatility,and a simple man...Ferroelectric capacitors hold great promise for non-volatile memory applications.However,the challenge lies in fabricating resistive switching devices with a high on/off ratio,excellent non-volatility,and a simple manufacturing process.Here,a novel approach is introduced by demonstrating the efficacy of the coupling effect between ferroelectric polarization and oxygen vacancy-based conductive filaments in Hf_(0.5)Zr_(0.5)O_(2)(HZO)films for the creation of non-volatile resistive switching memory devices,achieving an impressive on/off ratio of 6.8×10^(3) at+1.8 V.An in-depth exploration of the resistive switching mechanism is provided and subsequently the outstanding durability and retention characteristics of these devices for resistive switching is validated.Furthermore,the device's capacity to emulate non-volatile synaptic functionalities is assessed.Our results reveal that under pulsed conditions of 1 V/-2 V with 1µs pulses spaced 50 ms apart,the device can robustly achieve potentiation/depression synaptic plasticity,while exhibiting energy consumption(0.16 fJ for potentiation,0.12 fJ for depression)reduced by 1-2 orders of magnitude compared to biological synapses.This work holds significant value as a reference for the fabrication of energy-efficient,non-volatile memory and synaptic devices.展开更多
As artificial intelligence and big data become increasingly prevalent, resistive random-access memory (RRAM) has become one of the most promising alternatives for storing massive amounts of data. In this study, we emp...As artificial intelligence and big data become increasingly prevalent, resistive random-access memory (RRAM) has become one of the most promising alternatives for storing massive amounts of data. In this study, we employed high-quality crystalline TiN/Al_(2)O_(3)/BaTiO_(3)/Pt RRAM with an optimized thin Al_(2)O_(3) interlayer around 12 nm thick prepared using atomic layer deposition since the thickness of the interlayer affects the memory window size. After insertion of the Al_(2)O_(3) interlayer, the novel RRAM exhibited outstanding uniform resistive switching voltage and the ON/OFF memory window drastically increased from 10 to 103 without any discernible decline in performance. Moreover, the low-resistance state and high-resistance state operating current values decreased by almost one order and three orders of magnitude, respectively, thereby decreasing the power consumption for the RESET and SET processes by more than three and almost one order of magnitude, respectively. The device also exhibits multilevel resistive switching behavior when varying the applied voltage. Finally, we also developed a 6 6 crossbar array which demonstrated consistent and reliable resistive switching behavior with minimal variation. Hence, our approach holds great promise for producing state-of-the-art non-volatile resistive switching devices.展开更多
Reducing the process variation is a significant concern for resistive random access memory(RRAM).Due to its ultrahigh integration density,RRAM arrays are prone to lithographic variation during the lithography process,...Reducing the process variation is a significant concern for resistive random access memory(RRAM).Due to its ultrahigh integration density,RRAM arrays are prone to lithographic variation during the lithography process,introducing electrical variation among different RRAM devices.In this work,an optical physical verification methodology for the RRAM array is developed,and the effects of different layout parameters on important electrical characteristics are systematically investigated.The results indicate that the RRAM devices can be categorized into three clusters according to their locations and lithography environments.The read resistance is more sensitive to the locations in the array(~30%)than SET/RESET voltage(<10%).The increase in the RRAM device length and the application of the optical proximity correction technique can help to reduce the variation to less than 10%,whereas it reduces RRAM read resistance by 4×,resulting in a higher power and area consumption.As such,we provide design guidelines to minimize the electrical variation of RRAM arrays due to the lithography process.展开更多
Embedded memory,which heavily relies on the manufacturing process,has been widely adopted in various industrial applications.As the field of embedded memory continues to evolve,innovative strategies are emerging to en...Embedded memory,which heavily relies on the manufacturing process,has been widely adopted in various industrial applications.As the field of embedded memory continues to evolve,innovative strategies are emerging to enhance performance.Among them,resistive random access memory(RRAM)has gained significant attention due to its numerousadvantages over traditional memory devices,including high speed(<1 ns),high density(4 F^(2)·n^(-1)),high scalability(~nm),and low power consumption(~pJ).This review focuses on the recent progress of embedded RRAM in industrial manufacturing and its potentialapplications.It provides a brief introduction to the concepts and advantages of RRAM,discusses the key factors that impact its industrial manufacturing,and presents the commercial progress driven by cutting-edge nanotechnology,which has been pursued by manysemiconductor giants.Additionally,it highlights the adoption of embedded RRAM in emerging applications within the realm of the Internet of Things and future intelligent computing,with a particular emphasis on its role in neuromorphic computing.Finally,the review discusses thecurrent challenges and provides insights into the prospects of embedded RRAM in the era of big data and artificial intelligence.展开更多
Computing-in-memory(CIM)has been a promising candidate for artificial-intelligent applications thanks to the absence of data transfer between computation and storage blocks.Resistive random access memory(RRAM)based CI...Computing-in-memory(CIM)has been a promising candidate for artificial-intelligent applications thanks to the absence of data transfer between computation and storage blocks.Resistive random access memory(RRAM)based CIM has the advantage of high computing density,non-volatility as well as high energy efficiency.However,previous CIM research has predominantly focused on realizing high energy efficiency and high area efficiency for inference,while little attention has been devoted to addressing the challenges of on-chip programming speed,power consumption,and accuracy.In this paper,a fabri-cated 28 nm 576K RRAM-based CIM macro featuring optimized on-chip programming schemes is proposed to address the issues mentioned above.Different strategies of mapping weights to RRAM arrays are compared,and a novel direct-current ADC design is designed for both programming and inference stages.Utilizing the optimized hybrid programming scheme,4.67×programming speed,0.15×power saving and 4.31×compact weight distribution are realized.Besides,this macro achieves a normalized area efficiency of 2.82 TOPS/mm2 and a normalized energy efficiency of 35.6 TOPS/W.展开更多
With the rapid development of data-driven human interaction,advanced datastorage technologies with lower power consumption,larger storage capacity,faster switching speed,and higher integration density have become the ...With the rapid development of data-driven human interaction,advanced datastorage technologies with lower power consumption,larger storage capacity,faster switching speed,and higher integration density have become the goals of future memory electronics.Nevertheless,the physical limitations of conventional Si-based binary storage systems lag far behind the ultrahigh-density requirements of post-Moore information storage.In this regard,the pursuit of alternatives and/or supplements to the existing storage technology has come to the forefront.Recently,organic-based resistive memory materials have emerged as promising candidates for next-generation information storage applications,which provide new possibilities of realizing high-performance organic electronics.Herein,the memory device structure,switching types,mechanisms,and recent advances in organic resistive memory materials are reviewed.In particular,their potential of fulfilling multilevel storage is summarized.Besides,the present challenges and future prospects confronted by organic resistive memory materials and devices are discussed.展开更多
This paper presents a group-based dynamic stuck-at fault diagnosis scheme intended for resistive randomaccess memory(ReRAM).Traditional static random-access memory,dynamic random-access memory,NAND,and NOR flash memor...This paper presents a group-based dynamic stuck-at fault diagnosis scheme intended for resistive randomaccess memory(ReRAM).Traditional static random-access memory,dynamic random-access memory,NAND,and NOR flash memory are limited by their scalability,power,package density,and so forth.Next-generation memory types like ReRAMs are considered to have various advantages such as high package density,non-volatility,scalability,and low power consumption,but cell reliability has been a problem.Unreliable memory operation is caused by permanent stuck-at faults due to extensive use of write-or memory-intensive workloads.An increased number of stuck-at faults also prematurely limit chip lifetime.Therefore,a cellular automaton(CA)based dynamic stuck-at fault-tolerant design is proposed here to combat unreliable cell functioning and variable cell lifetime issues.A scalable,block-level fault diagnosis and recovery scheme is introduced to ensure readable data despite multi-bit stuck-at faults.The scheme is a novel approach because its goal is to remove all the restrictions on the number and nature of stuck-at faults in general fault conditions.The proposed scheme is based on Wolfram’s null boundary and periodic boundary CA theory.Various special classes of CAs are introduced for 100%fault tolerance:single-lengthcycle single-attractor cellular automata(SACAs),single-length-cycle two-attractor cellular automata(TACAs),and single-length-cycle multiple-attractor cellular automata(MACAs).The target micro-architectural unit is designed with optimal space overhead.展开更多
The resistive switching characteristics of TiO_2 nanowire networks directly grown on Ti foil by a single-step hydrothermal technique are discussed in this paper. The Ti foil serves as the supply of Ti atoms for growth...The resistive switching characteristics of TiO_2 nanowire networks directly grown on Ti foil by a single-step hydrothermal technique are discussed in this paper. The Ti foil serves as the supply of Ti atoms for growth of the TiO_2 nanowires, making the preparation straightforward. It also acts as a bottom electrode for the device. A top Al electrode was fabricated by e-beam evaporation process. The Al/TiO_2 nanowire networks/Ti device fabricated in this way displayed a highly repeatable and electroforming-free bipolar resistive behavior with retention for more than 10~4 s and an OFF/ON ratio of approximately 70. The switching mechanism of this Al/TiO_2 nanowire networks/Ti device is suggested to arise from the migration of oxygen vacancies under applied electric field. This provides a facile way to obtain metal oxide nanowire-based Re RAM device in the future.展开更多
This review summarizes the mechanism and performance of metal oxide based resistive switching memory. The origin of resistive switching （RS） behavior can be roughly classified into the conducting filament type and t...This review summarizes the mechanism and performance of metal oxide based resistive switching memory. The origin of resistive switching （RS） behavior can be roughly classified into the conducting filament type and the interface type. Here, we adopt the filament type to study the metal oxide based resistive switch- ing memory, which considers the migration of metallic cations and oxygen vacancies, as well as discuss two main mechanisms including the electrochemical metallization effect （ECM） and valence change memory effect （VCM）. At the light of the influence of the electrode materials and switching layers on the RS char- acteristics, an overview has also been given on the performance parameters including the uniformity, endurance, the retention, and the multi-layer storage. Especially, we mentioned ITO （indium tin oxide） electrode and discussed the novel RS characteristics related with ITO. Finally, the challenges resistive random access memory （RRAM） device is facing, as well as the future development trend, are expressed.展开更多
The resistive switching memory characteristics of 100 randomly measured devices were observed by reducing device size in a Cr/Cr Ox/Ti Ox/Ti N structure for the first time.Transmission electron microscope image confir...The resistive switching memory characteristics of 100 randomly measured devices were observed by reducing device size in a Cr/Cr Ox/Ti Ox/Ti N structure for the first time.Transmission electron microscope image confirmed a viahole size of 0.4 lm.A 3-nm-thick amorphous Ti Oxwith 4-nm-thick polycrystalline Cr Oxlayer was observed.A small 0.4-lm device shows reversible resistive switching at a current compliance of 300 l A as compared to other larger size devices(1–8 lm)owing to reduction of leakage current through the Ti Oxlayer.Good device-to-device uniformity with a yield of[85%has been clarified by weibull distribution owing to higher slope/shape factor.The switching mechanism is based on oxygen vacancy migration from the Cr Oxlayer and filament formation/rupture in the Ti Oxlayer.Long read pulse endurance of[105cycles,good data retention of 6 h,and a program/erase speed of 1 ls pulse width have been obtained.展开更多
For Pt(Ag)/ZnO single-layer/Pt structure,random 10 formation and rupture of conductive filaments composed by oxygen vacancies or metallic ions often cause dispersion problems of resistive switching(RS)parameters,which...For Pt(Ag)/ZnO single-layer/Pt structure,random 10 formation and rupture of conductive filaments composed by oxygen vacancies or metallic ions often cause dispersion problems of resistive switching(RS)parameters,which is disadvantageous to devices application.In this study,ZnO/CoOx/ZnO(ZCZ)tri-layers were utilized as the switching layers to investigate their RS properties as compared with ZnO-based single-layer devices.It is interestingly noted that Pt/ZCZ/Pt devices show quite stable bipolar RS behaviors with little resistance value fluctuations compared to Ag/ZCZ/Pt devices and Pt(Ag)/ZnO/Pt devices,which minimize the dispersion of the resistances of RS.This highly stable RS effect of Pt/ZCZ/Pt structure would be promising for high density memory devices.展开更多
In this letter,the Ta/HfO/BN/TiN resistive switching devices are fabricated and they exhibit low power consumption and high uniformity each.The reset current is reduced for the HfO/BN bilayer device compared with that...In this letter,the Ta/HfO/BN/TiN resistive switching devices are fabricated and they exhibit low power consumption and high uniformity each.The reset current is reduced for the HfO/BN bilayer device compared with that for the Ta/HfO/TiN structure.Furthermore,the reset current decreases with increasing BN thickness.The HfOlayer is a dominating switching layer,while the low-permittivity and high-resistivity BN layer acts as a barrier of electrons injection into TiN electrode.The current conduction mechanism of low resistance state in the HfO/BN bilayer device is space-chargelimited current(SCLC),while it is Ohmic conduction in the HfOdevice.展开更多
Transient electronics has attracted interest as an emerging technology to solve electronic-waste problem,due to its physically vanishing ability in solution.Here in this work,we demonstrate a flexible and degradable t...Transient electronics has attracted interest as an emerging technology to solve electronic-waste problem,due to its physically vanishing ability in solution.Here in this work,we demonstrate a flexible and degradable transient resistive switching(RS) memory device with simple structure of Cu/sodium alginate(SA)/ITO.The device presents excellent RS characteristics as well as high flexibility,including low operating voltage(<1.5 V) and multilevel RS behavior.No performance degradation occurs after bending the device 50 times.Moreover,our device can be absolutely dissolved in deionized water.The proposed SA-based transient memory device has great potential for the development of green and security memory devices.展开更多
The resistive random access memory(RRAM)has stimulated a variety of promising applications including programmable analog circuit,massive data storage,neuromorphic computing,etc.These new emerging applications have hug...The resistive random access memory(RRAM)has stimulated a variety of promising applications including programmable analog circuit,massive data storage,neuromorphic computing,etc.These new emerging applications have huge demands on high integration density and low power consumption.The cross-point configuration or passive array,which offers the smallest footprint of cell size and feasible capability of multi-layer stacking,has received broad attention from the research community.In such array,correct operation of reading and writing on a cell relies on effective elimination of the sneaking current coming from the neighboring cells.This target requires nonlinear I-V characteristics of the memory cell,which can be realized by either adding separate selector or developing implicit build-in nonlinear cells.The performance of a passive array largely depends on the cell nonlinearity,reliability,on/off ratio,line resistance,thermal coupling,etc.This article provides a comprehensive review on the progress achieved concerning 3D RRAM integration.First,the authors start with a brief overview of the associative problems in passive array and the category of 3D architectures.Next,the state of the arts on the development of various selector devices and self-selective cells are presented.Key parameters that influence the device nonlinearity and current density are outlined according to the corresponding working principles.Then,the reliability issues in 3D array are summarized in terms of uniformity,endurance,retention,and disturbance.Subsequently,scaling issue and thermal crosstalk in 3D memory array are thoroughly discussed,and applications of 3D RRAM beyond storage,such as neuromorphic computing and CMOL circuit are discussed later.Summary and outlooks are given in the final.展开更多
Facing the growing data storage and computing demands, a high accessing speed memory with low power and non- volatile character is urgently needed. Resistive access random memory with 4F2 cell size, switching in sub-n...Facing the growing data storage and computing demands, a high accessing speed memory with low power and non- volatile character is urgently needed. Resistive access random memory with 4F2 cell size, switching in sub-nanosecond, cycling endurances of over 1012 cycles, and information retention exceeding 10 years, is considered as promising next- generation non-volatile memory. However, the energy per bit is still too high to compete against static random access memory and dynamic random access memory. The sneak leakage path and metal film sheet resistance issues hinder the further scaling down. The variation of resistance between different devices and even various cycles in the same device, hold resistive access random memory back from commercialization. The emerging of atomic crystals, possessing fine interface without dangling bonds in low dimension, can provide atomic level solutions for the obsessional issues. Moreover, the unique properties of atomic crystals also enable new type resistive switching memories, which provide a brand-new direction for the resistive access random memory.展开更多
Metal phthalocyanine is considered one of the most promising candidates for the design and fabrication of flexible resistive random access memory(RRAM)devices due to its intrinsic flexibility and excellent functionali...Metal phthalocyanine is considered one of the most promising candidates for the design and fabrication of flexible resistive random access memory(RRAM)devices due to its intrinsic flexibility and excellent functionality.However,performance degradation and the lack of multi-level capability,which can directly expand the storage capacity in one memory cell without sacrificing additional layout area,are the primary obstacles to the use of metal phthalocyanine RRAMs in information storage.Here,a flexible RRAM with pristine nickel phthalocyanine(Ni Pc)as the resistive layer is reported for multi-level data storage.Due to its high trap-concentration,the charge transport behavior of the device agrees well with classical space charge limited conduction controlled by traps,leading to an excellent performance,including a high on-off current ratio of 10^(7),a long-term retention of 10^(6)s,a reproducible endurance over6000 cycles,long-term flexibility at a bending strain of 0.6%,a write speed of 50 ns under sequential bias pulses and the capability of multi-level data storage with reliable retention and uniformity.展开更多
With the progress of the semiconductor industry,the resistive random-access memory（RAM） has drawn increasing attention.The discovery of the memristor has brought much attention to this study.Research has focused on ...With the progress of the semiconductor industry,the resistive random-access memory（RAM） has drawn increasing attention.The discovery of the memristor has brought much attention to this study.Research has focused on the resistive switching characteristics of different materials and the analysis of resistive switching mechanisms.We discuss the resistive switching mechanisms of different materials in this paper and analyze the differences of those mechanisms from the view point of circuitry to establish their respective circuit models.Finally,simulations are presented.We give the prospect of using different materials in resistive RAM on account of their resistive switching mechanisms,which are applied to explain their resistive switchings.展开更多
The tail bits of intermediate resistance states（IRSs） achieved in the SET process（IRSS） and the RESET process（IRSR） of conductive-bridge random-access memory were investigated. Two types of tail bits were observ...The tail bits of intermediate resistance states（IRSs） achieved in the SET process（IRSS） and the RESET process（IRSR） of conductive-bridge random-access memory were investigated. Two types of tail bits were observed, depending on the filament morphology after the SET/RESET operation.（i） Tail bits resulting from lateral diffusion of Cu ions introduced an abrupt increase of device resistance from IRS to ultrahigh-resistance state, which mainly happened in IRSS.（ii） Tail bits induced by the vertical diffusion of Cu ions showed a gradual shift of resistance toward lower value. Statistical results show that more than 95% of tail bits are generated in IRSS. To achieve a reliable IRS for multilevel cell（MLC） operation, it is desirable to program the IRS in RESET operation. The mechanism of tail bit generation that is disclosed here provides a clear guideline for the data retention optimization of MLC resistive random-access memory cells.展开更多
As an industry accepted storage scheme, hafnium oxide（HfO_x） based resistive random access memory（RRAM）should further improve its thermal stability and data retention for practical applications. We therefore fabri...As an industry accepted storage scheme, hafnium oxide（HfO_x） based resistive random access memory（RRAM）should further improve its thermal stability and data retention for practical applications. We therefore fabricated RRAMs with HfO_x/ZnO double-layer as the storage medium to study their thermal stability as well as data retention. The HfO_x/ZnO double-layer is capable of reversible bipolar switching under ultralow switching current（〈 3 μA） with a Schottky emission dominant conduction for the high resistance state and a Poole–Frenkel emission governed conduction for the low resistance state. Compared with a drastically increased switching current at 120℃ for the single HfO_x layer RRAM, the HfO_x/ZnO double-layer exhibits excellent thermal stability and maintains neglectful fluctuations in switching current at high temperatures（up to 180℃）, which might be attributed to the increased Schottky barrier height to suppress current at high temperatures. Additionally, the HfO_x/ZnO double-layer exhibits 10-year data retention @85℃ that is helpful for the practical applications in RRAMs.展开更多
Graphene-based resistive random access memory （GRRAM） has grasped researchers＇ attention due to its merits com- pared with ordinary RRAM. In this paper, we briefly review different types of GRRAMs. These GRRAMs can...Graphene-based resistive random access memory （GRRAM） has grasped researchers＇ attention due to its merits com- pared with ordinary RRAM. In this paper, we briefly review different types of GRRAMs. These GRRAMs can be divided into two categories： graphene RRAM and graphene oxide （GO）/reduced graphene oxide （rGO） RRAM. Using graphene as the electrode, GRRAM can own many good characteristics, such as low power consumption, higher density, transparency, SET voltage modulation, high uniformity, and so on. Graphene flakes sandwiched between two dielectric layers can lower the SET voltage and achieve multilevel switching. Moreover, the GRRAM with rGO and GO as the dielectric or electrode can be simply fabricated. Flexible and high performance RRAM and GO film can be modified by adding other materials layer or making a composite with polymer, nanoparticle, and 2D materials to further improve the performance. Above all, GRRAM shows huge potential to become the next generation memory.展开更多
基金supported by the National Natu-ral Science Foundation of China(Nos.52250281,62204088 and 62174059)the Science and Technology Projects in Guangzhou(No.202201000008)+1 种基金the Guangdong Provincial Key Laboratory of Optical Information Materials and Technology(No.2017B030301007)the South China Normal University Youth Teacher Research and Training Fund(No.22KJ10).
文摘Ferroelectric capacitors hold great promise for non-volatile memory applications.However,the challenge lies in fabricating resistive switching devices with a high on/off ratio,excellent non-volatility,and a simple manufacturing process.Here,a novel approach is introduced by demonstrating the efficacy of the coupling effect between ferroelectric polarization and oxygen vacancy-based conductive filaments in Hf_(0.5)Zr_(0.5)O_(2)(HZO)films for the creation of non-volatile resistive switching memory devices,achieving an impressive on/off ratio of 6.8×10^(3) at+1.8 V.An in-depth exploration of the resistive switching mechanism is provided and subsequently the outstanding durability and retention characteristics of these devices for resistive switching is validated.Furthermore,the device's capacity to emulate non-volatile synaptic functionalities is assessed.Our results reveal that under pulsed conditions of 1 V/-2 V with 1µs pulses spaced 50 ms apart,the device can robustly achieve potentiation/depression synaptic plasticity,while exhibiting energy consumption(0.16 fJ for potentiation,0.12 fJ for depression)reduced by 1-2 orders of magnitude compared to biological synapses.This work holds significant value as a reference for the fabrication of energy-efficient,non-volatile memory and synaptic devices.
基金supported by the National Research Foundation of Korea funded by the Korean Government(grant No.RS-2023-00208801).
文摘As artificial intelligence and big data become increasingly prevalent, resistive random-access memory (RRAM) has become one of the most promising alternatives for storing massive amounts of data. In this study, we employed high-quality crystalline TiN/Al_(2)O_(3)/BaTiO_(3)/Pt RRAM with an optimized thin Al_(2)O_(3) interlayer around 12 nm thick prepared using atomic layer deposition since the thickness of the interlayer affects the memory window size. After insertion of the Al_(2)O_(3) interlayer, the novel RRAM exhibited outstanding uniform resistive switching voltage and the ON/OFF memory window drastically increased from 10 to 103 without any discernible decline in performance. Moreover, the low-resistance state and high-resistance state operating current values decreased by almost one order and three orders of magnitude, respectively, thereby decreasing the power consumption for the RESET and SET processes by more than three and almost one order of magnitude, respectively. The device also exhibits multilevel resistive switching behavior when varying the applied voltage. Finally, we also developed a 6 6 crossbar array which demonstrated consistent and reliable resistive switching behavior with minimal variation. Hence, our approach holds great promise for producing state-of-the-art non-volatile resistive switching devices.
基金supported in part by the Open Fund of State Key Laboratory of Integrated Chips and Systems,Fudan Universityin part by the National Science Foundation of China under Grant No.62304133 and No.62350610271.
文摘Reducing the process variation is a significant concern for resistive random access memory(RRAM).Due to its ultrahigh integration density,RRAM arrays are prone to lithographic variation during the lithography process,introducing electrical variation among different RRAM devices.In this work,an optical physical verification methodology for the RRAM array is developed,and the effects of different layout parameters on important electrical characteristics are systematically investigated.The results indicate that the RRAM devices can be categorized into three clusters according to their locations and lithography environments.The read resistance is more sensitive to the locations in the array(~30%)than SET/RESET voltage(<10%).The increase in the RRAM device length and the application of the optical proximity correction technique can help to reduce the variation to less than 10%,whereas it reduces RRAM read resistance by 4×,resulting in a higher power and area consumption.As such,we provide design guidelines to minimize the electrical variation of RRAM arrays due to the lithography process.
基金supported by the Key-Area Research and Development Program of Guangdong Province(Grant No.2021B0909060002)National Natural Science Foundation of China(Grant Nos.62204219,62204140)+1 种基金Major Program of Natural Science Foundation of Zhejiang Province(Grant No.LDT23F0401)Thanks to Professor Zhang Yishu from Zhejiang University,Professor Gao Xu from Soochow University,and Professor Zhong Shuai from Guangdong Institute of Intelligence Science and Technology for their support。
文摘Embedded memory,which heavily relies on the manufacturing process,has been widely adopted in various industrial applications.As the field of embedded memory continues to evolve,innovative strategies are emerging to enhance performance.Among them,resistive random access memory(RRAM)has gained significant attention due to its numerousadvantages over traditional memory devices,including high speed(<1 ns),high density(4 F^(2)·n^(-1)),high scalability(~nm),and low power consumption(~pJ).This review focuses on the recent progress of embedded RRAM in industrial manufacturing and its potentialapplications.It provides a brief introduction to the concepts and advantages of RRAM,discusses the key factors that impact its industrial manufacturing,and presents the commercial progress driven by cutting-edge nanotechnology,which has been pursued by manysemiconductor giants.Additionally,it highlights the adoption of embedded RRAM in emerging applications within the realm of the Internet of Things and future intelligent computing,with a particular emphasis on its role in neuromorphic computing.Finally,the review discusses thecurrent challenges and provides insights into the prospects of embedded RRAM in the era of big data and artificial intelligence.
基金supported in part by the National Natural Science Foundation of China (62422405, 62025111,62495100, 92464302)the STI 2030-Major Projects(2021ZD0201200)+1 种基金the Shanghai Municipal Science and Technology Major Projectthe Beijing Advanced Innovation Center for Integrated Circuits
文摘Computing-in-memory(CIM)has been a promising candidate for artificial-intelligent applications thanks to the absence of data transfer between computation and storage blocks.Resistive random access memory(RRAM)based CIM has the advantage of high computing density,non-volatility as well as high energy efficiency.However,previous CIM research has predominantly focused on realizing high energy efficiency and high area efficiency for inference,while little attention has been devoted to addressing the challenges of on-chip programming speed,power consumption,and accuracy.In this paper,a fabri-cated 28 nm 576K RRAM-based CIM macro featuring optimized on-chip programming schemes is proposed to address the issues mentioned above.Different strategies of mapping weights to RRAM arrays are compared,and a novel direct-current ADC design is designed for both programming and inference stages.Utilizing the optimized hybrid programming scheme,4.67×programming speed,0.15×power saving and 4.31×compact weight distribution are realized.Besides,this macro achieves a normalized area efficiency of 2.82 TOPS/mm2 and a normalized energy efficiency of 35.6 TOPS/W.
基金Jiangsu Key Disciplines of the Thirteenth Five-Year Plan,Grant/Award Number:20168765Six Talent Peaks Project of Jiangsu Province,Grant/Award Number:XCL-078+4 种基金NSF of Jiangsu Higher Education Institutions,Grant/Award Number:17KJA140001National Excellent Doctoral Dissertation funds of China,Grant/Award Number:201455National Natural Science Foundation of China,Grant/Award Numbers:21878199,21938006Undergraduate Innovation and Entrepreneurship Training Program of Jiangsu Province,Grant/Award Number:201910332067YNatural Science Foundation of the Jiangsu Higher。
文摘With the rapid development of data-driven human interaction,advanced datastorage technologies with lower power consumption,larger storage capacity,faster switching speed,and higher integration density have become the goals of future memory electronics.Nevertheless,the physical limitations of conventional Si-based binary storage systems lag far behind the ultrahigh-density requirements of post-Moore information storage.In this regard,the pursuit of alternatives and/or supplements to the existing storage technology has come to the forefront.Recently,organic-based resistive memory materials have emerged as promising candidates for next-generation information storage applications,which provide new possibilities of realizing high-performance organic electronics.Herein,the memory device structure,switching types,mechanisms,and recent advances in organic resistive memory materials are reviewed.In particular,their potential of fulfilling multilevel storage is summarized.Besides,the present challenges and future prospects confronted by organic resistive memory materials and devices are discussed.
文摘This paper presents a group-based dynamic stuck-at fault diagnosis scheme intended for resistive randomaccess memory(ReRAM).Traditional static random-access memory,dynamic random-access memory,NAND,and NOR flash memory are limited by their scalability,power,package density,and so forth.Next-generation memory types like ReRAMs are considered to have various advantages such as high package density,non-volatility,scalability,and low power consumption,but cell reliability has been a problem.Unreliable memory operation is caused by permanent stuck-at faults due to extensive use of write-or memory-intensive workloads.An increased number of stuck-at faults also prematurely limit chip lifetime.Therefore,a cellular automaton(CA)based dynamic stuck-at fault-tolerant design is proposed here to combat unreliable cell functioning and variable cell lifetime issues.A scalable,block-level fault diagnosis and recovery scheme is introduced to ensure readable data despite multi-bit stuck-at faults.The scheme is a novel approach because its goal is to remove all the restrictions on the number and nature of stuck-at faults in general fault conditions.The proposed scheme is based on Wolfram’s null boundary and periodic boundary CA theory.Various special classes of CAs are introduced for 100%fault tolerance:single-lengthcycle single-attractor cellular automata(SACAs),single-length-cycle two-attractor cellular automata(TACAs),and single-length-cycle multiple-attractor cellular automata(MACAs).The target micro-architectural unit is designed with optimal space overhead.
基金supported by the Natural Sciences and Engineering Research Council(NSERC)of CanadaThe financial support of the State Scholarship Fund of China(No.201506160061)
文摘The resistive switching characteristics of TiO_2 nanowire networks directly grown on Ti foil by a single-step hydrothermal technique are discussed in this paper. The Ti foil serves as the supply of Ti atoms for growth of the TiO_2 nanowires, making the preparation straightforward. It also acts as a bottom electrode for the device. A top Al electrode was fabricated by e-beam evaporation process. The Al/TiO_2 nanowire networks/Ti device fabricated in this way displayed a highly repeatable and electroforming-free bipolar resistive behavior with retention for more than 10~4 s and an OFF/ON ratio of approximately 70. The switching mechanism of this Al/TiO_2 nanowire networks/Ti device is suggested to arise from the migration of oxygen vacancies under applied electric field. This provides a facile way to obtain metal oxide nanowire-based Re RAM device in the future.
基金financial support from the National Natural Science Foundation of China(Nos.61474039 and 51572002)the Nature Science Foundation(Key Project) of Hubei Province (No.2015CFA052)
文摘This review summarizes the mechanism and performance of metal oxide based resistive switching memory. The origin of resistive switching （RS） behavior can be roughly classified into the conducting filament type and the interface type. Here, we adopt the filament type to study the metal oxide based resistive switch- ing memory, which considers the migration of metallic cations and oxygen vacancies, as well as discuss two main mechanisms including the electrochemical metallization effect （ECM） and valence change memory effect （VCM）. At the light of the influence of the electrode materials and switching layers on the RS char- acteristics, an overview has also been given on the performance parameters including the uniformity, endurance, the retention, and the multi-layer storage. Especially, we mentioned ITO （indium tin oxide） electrode and discussed the novel RS characteristics related with ITO. Finally, the challenges resistive random access memory （RRAM） device is facing, as well as the future development trend, are expressed.
基金supported by Ministry of Sci ence and Technology(MOST)Taiwan,under Contract no.NSC-1022221-E-182-057-MY2grateful to EOL/ITRI Hsinchu,Taiwan for their experimental support
文摘The resistive switching memory characteristics of 100 randomly measured devices were observed by reducing device size in a Cr/Cr Ox/Ti Ox/Ti N structure for the first time.Transmission electron microscope image confirmed a viahole size of 0.4 lm.A 3-nm-thick amorphous Ti Oxwith 4-nm-thick polycrystalline Cr Oxlayer was observed.A small 0.4-lm device shows reversible resistive switching at a current compliance of 300 l A as compared to other larger size devices(1–8 lm)owing to reduction of leakage current through the Ti Oxlayer.Good device-to-device uniformity with a yield of[85%has been clarified by weibull distribution owing to higher slope/shape factor.The switching mechanism is based on oxygen vacancy migration from the Cr Oxlayer and filament formation/rupture in the Ti Oxlayer.Long read pulse endurance of[105cycles,good data retention of 6 h,and a program/erase speed of 1 ls pulse width have been obtained.
基金supported by the National Natural Science Foundation of China (Nos.51231004 and 51202125)National Basic Research Program of China (No.2010CB832905)
文摘For Pt(Ag)/ZnO single-layer/Pt structure,random 10 formation and rupture of conductive filaments composed by oxygen vacancies or metallic ions often cause dispersion problems of resistive switching(RS)parameters,which is disadvantageous to devices application.In this study,ZnO/CoOx/ZnO(ZCZ)tri-layers were utilized as the switching layers to investigate their RS properties as compared with ZnO-based single-layer devices.It is interestingly noted that Pt/ZCZ/Pt devices show quite stable bipolar RS behaviors with little resistance value fluctuations compared to Ag/ZCZ/Pt devices and Pt(Ag)/ZnO/Pt devices,which minimize the dispersion of the resistances of RS.This highly stable RS effect of Pt/ZCZ/Pt structure would be promising for high density memory devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.61274113,11204212,61404091,51502203,and 51502204)the Tianjin Natural Science Foundation,China(Grant Nos.14JCZDJC31500 and 14JCQNJC00800)the Tianjin Science and Technology Developmental Funds of Universities and Colleges,China(Grant No.20130701)
文摘In this letter,the Ta/HfO/BN/TiN resistive switching devices are fabricated and they exhibit low power consumption and high uniformity each.The reset current is reduced for the HfO/BN bilayer device compared with that for the Ta/HfO/TiN structure.Furthermore,the reset current decreases with increasing BN thickness.The HfOlayer is a dominating switching layer,while the low-permittivity and high-resistivity BN layer acts as a barrier of electrons injection into TiN electrode.The current conduction mechanism of low resistance state in the HfO/BN bilayer device is space-chargelimited current(SCLC),while it is Ohmic conduction in the HfOdevice.
基金Project supported by the Fund from the Ministry of Science and Technology of China(Grant No.2018YFE0118300)the National Natural Science Foundation of China(Grant Nos.11974072,51902048,61774031,and 61574031)+3 种基金the“111”Project,China(Grant No.B13013)the China Postdoctoral Science Foundation,China(Grant No.2019M661185)the Fundamental Research Funds for the Central Universities,China(Grant No.2412019QD015)Science Fund from the Jilin Province,China(Grant No.JJKH20201163KJ)。
文摘Transient electronics has attracted interest as an emerging technology to solve electronic-waste problem,due to its physically vanishing ability in solution.Here in this work,we demonstrate a flexible and degradable transient resistive switching(RS) memory device with simple structure of Cu/sodium alginate(SA)/ITO.The device presents excellent RS characteristics as well as high flexibility,including low operating voltage(<1.5 V) and multilevel RS behavior.No performance degradation occurs after bending the device 50 times.Moreover,our device can be absolutely dissolved in deionized water.The proposed SA-based transient memory device has great potential for the development of green and security memory devices.
基金the National Key R&D Program of China(Grant Nos.2018YFB0407501 and 2016YFA0201800)the National Natural Science Foundation of China(Grant Nos.61804173,61922083,61804167,61904200,and 61821091)the fourth China Association for Science and Technology Youth Talent Support Project(Grant No.2019QNRC001).
文摘The resistive random access memory(RRAM)has stimulated a variety of promising applications including programmable analog circuit,massive data storage,neuromorphic computing,etc.These new emerging applications have huge demands on high integration density and low power consumption.The cross-point configuration or passive array,which offers the smallest footprint of cell size and feasible capability of multi-layer stacking,has received broad attention from the research community.In such array,correct operation of reading and writing on a cell relies on effective elimination of the sneaking current coming from the neighboring cells.This target requires nonlinear I-V characteristics of the memory cell,which can be realized by either adding separate selector or developing implicit build-in nonlinear cells.The performance of a passive array largely depends on the cell nonlinearity,reliability,on/off ratio,line resistance,thermal coupling,etc.This article provides a comprehensive review on the progress achieved concerning 3D RRAM integration.First,the authors start with a brief overview of the associative problems in passive array and the category of 3D architectures.Next,the state of the arts on the development of various selector devices and self-selective cells are presented.Key parameters that influence the device nonlinearity and current density are outlined according to the corresponding working principles.Then,the reliability issues in 3D array are summarized in terms of uniformity,endurance,retention,and disturbance.Subsequently,scaling issue and thermal crosstalk in 3D memory array are thoroughly discussed,and applications of 3D RRAM beyond storage,such as neuromorphic computing and CMOL circuit are discussed later.Summary and outlooks are given in the final.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61376093 and 61622401)the National Key Research and Development Program of China(Grant No.2016YFA0203900)
文摘Facing the growing data storage and computing demands, a high accessing speed memory with low power and non- volatile character is urgently needed. Resistive access random memory with 4F2 cell size, switching in sub-nanosecond, cycling endurances of over 1012 cycles, and information retention exceeding 10 years, is considered as promising next- generation non-volatile memory. However, the energy per bit is still too high to compete against static random access memory and dynamic random access memory. The sneak leakage path and metal film sheet resistance issues hinder the further scaling down. The variation of resistance between different devices and even various cycles in the same device, hold resistive access random memory back from commercialization. The emerging of atomic crystals, possessing fine interface without dangling bonds in low dimension, can provide atomic level solutions for the obsessional issues. Moreover, the unique properties of atomic crystals also enable new type resistive switching memories, which provide a brand-new direction for the resistive access random memory.
基金supported by National Natural Science Foundation of China(Nos.61574143,61704175,51502304)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB30000000)+2 种基金the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(No.ZDBS-LY-JSC027)Liaoning Revitalization Talents Program(No.XLYC1807109)the National Key Research and Development Program of China(2016YFB0401104)。
文摘Metal phthalocyanine is considered one of the most promising candidates for the design and fabrication of flexible resistive random access memory(RRAM)devices due to its intrinsic flexibility and excellent functionality.However,performance degradation and the lack of multi-level capability,which can directly expand the storage capacity in one memory cell without sacrificing additional layout area,are the primary obstacles to the use of metal phthalocyanine RRAMs in information storage.Here,a flexible RRAM with pristine nickel phthalocyanine(Ni Pc)as the resistive layer is reported for multi-level data storage.Due to its high trap-concentration,the charge transport behavior of the device agrees well with classical space charge limited conduction controlled by traps,leading to an excellent performance,including a high on-off current ratio of 10^(7),a long-term retention of 10^(6)s,a reproducible endurance over6000 cycles,long-term flexibility at a bending strain of 0.6%,a write speed of 50 ns under sequential bias pulses and the capability of multi-level data storage with reliable retention and uniformity.
基金Project supported by the National Natural Science Foundation of China (Grant No. 60921062)
文摘With the progress of the semiconductor industry,the resistive random-access memory（RAM） has drawn increasing attention.The discovery of the memristor has brought much attention to this study.Research has focused on the resistive switching characteristics of different materials and the analysis of resistive switching mechanisms.We discuss the resistive switching mechanisms of different materials in this paper and analyze the differences of those mechanisms from the view point of circuitry to establish their respective circuit models.Finally,simulations are presented.We give the prospect of using different materials in resistive RAM on account of their resistive switching mechanisms,which are applied to explain their resistive switchings.
基金Project supported by the Ministry of Science and Technology of China(Grant Nos.2016YFA0203800,2016YFA0201803,and 2018YFB0407502)the National Natural Science Foundation of China(Grant Nos.61522408,61334007,and 61521064)+1 种基金Beijing Municipal Science&Technology Commission Program,China(Grant No.Z161100000216153)Huawei Data Center Technology Laboratory
文摘The tail bits of intermediate resistance states（IRSs） achieved in the SET process（IRSS） and the RESET process（IRSR） of conductive-bridge random-access memory were investigated. Two types of tail bits were observed, depending on the filament morphology after the SET/RESET operation.（i） Tail bits resulting from lateral diffusion of Cu ions introduced an abrupt increase of device resistance from IRS to ultrahigh-resistance state, which mainly happened in IRSS.（ii） Tail bits induced by the vertical diffusion of Cu ions showed a gradual shift of resistance toward lower value. Statistical results show that more than 95% of tail bits are generated in IRSS. To achieve a reliable IRS for multilevel cell（MLC） operation, it is desirable to program the IRS in RESET operation. The mechanism of tail bit generation that is disclosed here provides a clear guideline for the data retention optimization of MLC resistive random-access memory cells.
基金supported by the National Natural Science Foundation of China(Grant Nos.61006003 and 61674038)the Natural Science Foundation of Fujian Province,China(Grant Nos.2015J01249 and 2010J05134)+1 种基金the Science Foundation of Fujian Education Department of China(Grant No.JAT160073)the Science Foundation of Fujian Provincial Economic and Information Technology Commission of China(Grant No.83016006)
文摘As an industry accepted storage scheme, hafnium oxide（HfO_x） based resistive random access memory（RRAM）should further improve its thermal stability and data retention for practical applications. We therefore fabricated RRAMs with HfO_x/ZnO double-layer as the storage medium to study their thermal stability as well as data retention. The HfO_x/ZnO double-layer is capable of reversible bipolar switching under ultralow switching current（〈 3 μA） with a Schottky emission dominant conduction for the high resistance state and a Poole–Frenkel emission governed conduction for the low resistance state. Compared with a drastically increased switching current at 120℃ for the single HfO_x layer RRAM, the HfO_x/ZnO double-layer exhibits excellent thermal stability and maintains neglectful fluctuations in switching current at high temperatures（up to 180℃）, which might be attributed to the increased Schottky barrier height to suppress current at high temperatures. Additionally, the HfO_x/ZnO double-layer exhibits 10-year data retention @85℃ that is helpful for the practical applications in RRAMs.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61574083 and 61434001)the National Basic Research Program of China(Grant No.2015CB352101)+4 种基金the National Key Research and Development Program of China(Grant No.2016YFA0200404)the National Key Project of Science and Technology of China(Grant No.2011ZX02403-002)Special Fund for Agroscientic Research in the Public Interest of China(Grant No.201303107)the Independent Research Program of Tsinghua University,China(Grant No.2014Z01006)Advanced Sensor and Integrated System Lab of Tsinghua University Graduate School at Shenzhen,China(Grant No.ZDSYS20140509172959969)
文摘Graphene-based resistive random access memory （GRRAM） has grasped researchers＇ attention due to its merits com- pared with ordinary RRAM. In this paper, we briefly review different types of GRRAMs. These GRRAMs can be divided into two categories： graphene RRAM and graphene oxide （GO）/reduced graphene oxide （rGO） RRAM. Using graphene as the electrode, GRRAM can own many good characteristics, such as low power consumption, higher density, transparency, SET voltage modulation, high uniformity, and so on. Graphene flakes sandwiched between two dielectric layers can lower the SET voltage and achieve multilevel switching. Moreover, the GRRAM with rGO and GO as the dielectric or electrode can be simply fabricated. Flexible and high performance RRAM and GO film can be modified by adding other materials layer or making a composite with polymer, nanoparticle, and 2D materials to further improve the performance. Above all, GRRAM shows huge potential to become the next generation memory.
