Article
Engineering, Electrical & Electronic
Zong-Rui Xu, Yi-Feng Ye, Bin Xia, Lin-Sheng Wu, Jun-Fa Mao, Yue-Yang Jia
Summary: In this study, three RF switches and a phase shifter were proposed using the CBRAM technique, with good agreement achieved among simulated, measured, and modeled results. The devices showed low insertion loss, good isolation, and independent control, indicating promising applications in reconfigurable RF circuits. Compared with conventional RF switchable devices, the proposed devices have the advantages of nonvolatility and low power consumption, making them suitable for mass production and various substrates.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2022)
Article
Nanoscience & Nanotechnology
Kai-Jhih Gan, Po-Tsun Liu, Dun-Bao Ruan, Chih-Chieh Hsu, Yu-Chuan Chiu, Simon M. Sze
Summary: The doping ratio of tungsten significantly influences the memory characteristics of CBRAM, with 15% tungsten doping ratio showing excellent memory properties such as high cycling endurance, low operating voltage, and good retention capability. Additionally, the electrical uniformity and switching behavior of InWZnO devices are improved as the doping ratio of tungsten in the switching layer increases, indicating great potential for high-performance memory devices based on novel material InWZnO.
Article
Computer Science, Hardware & Architecture
Ta-Ching Yu, Chin-Hsien Wu, Yan-Qi Liao
Summary: Nowadays, TLC NAND flash memory is widely used due to its large capacity and low cost. However, with the increase of cell capacity, reliability issues such as retention errors and read disturb errors may occur. To address these issues, a method is proposed to coordinate retention errors, read disturb errors and Huffman coding on TLC NAND flash memory by removing unsuitable states during different data accesses. Experimental results show that the proposed method can improve performance through Huffman coding compression and enhance the reliability of TLC NAND flash memory by removing vulnerable states.
IEEE TRANSACTIONS ON DEPENDABLE AND SECURE COMPUTING
(2023)
Article
Nanoscience & Nanotechnology
Florian Maudet, Adnan Hammud, Markus Wollgarten, Veeresh Deshpande, Catherine Dubourdieu
Summary: Conductive bridge random access memory devices, such as Cu/SiO2/W, have attracted attention in neuromorphic computing due to their fast, low-voltage switching, multiple-conductance states, scalability, low off-current, and compatibility with Si CMOS technologies. The conductance states are quantized and result from the formation of a Cu filament in the SiO2 electrolyte. The major challenge is the variability in the voltage required to switch the device. A statistical analysis of over 150 devices suggests that the activation energy distribution for copper ion diffusion in amorphous SiO2 plays a key role in the cycle-to-cycle variability. The study highlights the need for strategies to reduce the activation energy distribution in amorphous SiO2.
Article
Chemistry, Multidisciplinary
Jianhong Zhou, Zheng Wang, Yujun Fu, Zhichao Xie, Wei Xiao, Zhenli Wen, Qi Wang, Qiming Liu, Junyan Zhang, Deyan He
Summary: Conductive-bridging memristors based on metal ion redox mechanism have potential applications in future neuromorphic computing nanodevices due to their high resistance switch ratio, fast operating speed, low power consumption, and small size. However, the uncontrolled migration of metal ions results in random generation of conductive filaments and difficulty in accurately controlling the conductance state. In this study, an organic polymer carboxylated chitosan-based memristor doped with a small amount of conductive polymer PEDOT:PSS was reported to improve polymer ionic conductivity and regulate the redox of metal ions. The resulting device exhibited uniform conductive filaments, more than 100 non-volatile conductance states, and linear conductance regulation. Moreover, simulation using handwritten digital datasets showed a recognition accuracy of 93% for the carboxylated chitosan-doped PEDOT:PSS memristor array. This work provides a path to enhance the performance of metal ion-based memristors in artificial synapses.
Article
Computer Science, Hardware & Architecture
Sangwoo Han, Minjung Cho, Gi Lee, Eui-Young Chung
Summary: Read disturb is a phenomenon where unselected wordlines in a block are affected while reading a selected wordline, causing errors. To address this, read reclaim operations migrate deteriorated block data to a new free block when a preset threshold is exceeded. However, these operations result in decreased performance and reliability. To mitigate this, we propose a Page Type-aware Data Migration technique (PTDM) that migrates pages within blocks based on their vulnerability to read disturb. Shifting from block-level to page-level read reclaim improves memory efficiency, and distributing read-hot data across multiple blocks reduces read disturb impact. Experimental results show a significant reduction in RR data migration and overall erasure counts using our proposed method.
IEEE TRANSACTIONS ON VERY LARGE SCALE INTEGRATION (VLSI) SYSTEMS
(2023)
Review
Chemistry, Analytical
Haider Abbas, Jiayi Li, Diing Shenp Ang
Summary: With the rapid increase in data volume, there is a growing need for new memory technologies and computing systems. CBRAM, as an emerging technology, offers great opportunities for future memory and neuromorphic computing applications. This review thoroughly explores the principles, applications, challenges, and simulations of biological synapses and neurons using CBRAM devices fabricated with various materials and device engineering approaches.
Article
Engineering, Electrical & Electronic
Mor M. Dahan, Evelyn T. Breyer, Stefan Slesazeck, Thomas Mikolajick, Shahar Kvatinsky
Summary: This paper proposes a memory architecture called crossed-AND (C-AND) for FeFET memory, which addresses the asymmetric switching voltage issue and enables fast read and write operations for entire words. It also reduces read errors and write disturbs.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS
(2022)
Article
Engineering, Electrical & Electronic
Haider Abbas, Asif Ali, Jiayi Li, Thaw Tint Te Tun, Diing Shenp Ang
Summary: This work demonstrates resistive switching characteristics in conductive bridge RAM devices based on transition-metal chalcogenides, which are forming-free and self-limited. By using a suitable solid electrolyte, the proposed WTe2-based devices show excellent switching characteristics, including high pulse endurance (> 2 x 10(7) cycles) and stable data retention (10 years at 72 degrees C). The devices also exhibit good device-to-device and cycle-to-cycle uniformity, making them suitable for practical implementation in large crossbar arrays.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Engineering, Electrical & Electronic
J. Aeschlimann, M. H. Bani-Hashemian, F. Ducry, A. Emboras, M. Luisier
Summary: We introduce a simulation framework for investigating the switching behavior of Ag/a-SiO2 conductive bridging random access memories (CBRAM). The dynamics of the switching process is studied using classical molecular dynamics simulations, while the electrical properties are determined through ab initio calculations. Structural analysis of the oxide reveals that the switching mechanism depends on preferred channels with wide SiO2 rings for Ag+ ion migration. Additionally, we demonstrate that manipulating a few atoms within these channels can drastically change the resistance state.
SOLID-STATE ELECTRONICS
(2023)
Article
Physics, Applied
Calvin Xiu Xian Lee, Putu Andhita Dananjaya, Mun Yin Chee, Han Yin Poh, Funan Tan, Jia Rui Thong, Lingli Liu, Gerard Joseph Lim, Yuanmin Du, Juan Boon Tan, Wen Siang Lew
Summary: The resistive switching variability of CBRAM devices is significantly improved by employing Co-Cu alloy as the active electrode, resulting in improved filament stability and device performance. Through experimental results and a physical model, the advantages of Co70Cu30 alloy in CBRAM have been demonstrated, highlighting the significant influence of the relative proportion between Co and Cu on the device performance.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Cheng-Min Jiang, Chih-Chieh Wang, Kai-Shin Li, Chao-Cheng Lin, Tahui Wang
Summary: The study reveals that read-disturb failure time in the low resistance state of a hafnium-oxide resistive memory cell degrades significantly after SET/RESET cycling. An analytical model is developed to describe this degradation, and it shows good agreement with measured results. Different read failure criteria also have an impact on read-disturb failure time in post-cycling cells.
IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY
(2021)
Article
Computer Science, Information Systems
Stefan Pechmann, Timo Mai, Matthias Voelkel, Mamathamba K. Mahadevaiah, Eduardo Perez, Emilio Perez-Bosch Quesada, Marc Reichenbach, Christian Wenger, Amelie Hagelauer
Summary: An integrated read and programming circuit for RRAM cells with versatility in adapting to different cell properties was presented. The circuit is suitable for read and programming operations based on voltage pulses, and can distinguish up to eight different states, achieving digitization of analog memory values. The functionality of the circuit and system was proven through measurement results, with the ability to distinguish up to eight different states and an overall resistance ratio of 7.9.
Article
Engineering, Electrical & Electronic
Jong-Hyeok Yoon, Muya Chang, Win-San Khwa, Yu-Der Chih, Meng-Fan Chang, Arijit Raychowdhury
Summary: RRAM is a promising candidate for computing-in-memory architectures due to its advantages in efficiency and density, although reliability issues require a joint approach with circuit technology. This article introduces a hybrid CIM/digital RRAM macro with various functions, achieving high energy efficiency and performance goals.
IEEE JOURNAL OF SOLID-STATE CIRCUITS
(2022)
Article
Engineering, Electrical & Electronic
Jiaxun Lv, Zilin Wang, Maohang Huang, Yajuan He
Summary: This paper introduces a novel 9T SRAM cell with a data-aware write-word-line structure and a positive feedback sense amplifier to enhance write ability and address sensing challenges at ultra-low voltages. Simulation results demonstrate that the proposed cell achieves comparable read performance to the conventional 8T SRAM cell at 0.5V supply voltage, while significantly improving write margin. This design also leads to a substantial reduction in leakage power consumption compared to the 8T SRAM cell in a 40nm standard CMOS technology.
INTERNATIONAL JOURNAL OF ELECTRONICS
(2022)
Article
Chemistry, Multidisciplinary
Wouter Mortelmans, Karel De Smet, Ruishen Meng, Michel Houssa, Stefan De Gendt, Marc Heyns, Clement Merckling
Summary: This study focuses on understanding the formation of 60 degrees twins in (quasi-)vdW epitaxy of 2D chalcogenides. Experimental and theoretical results show that the stronger interlayer vdW coupling in Bi2Se3 compared to WSe2 leads to reduced twin occurrence, indicating promising potential for defect-free epitaxial integration. This aspect of (quasi-)vdW epitaxy highlights the importance of interlayer vdW coupling strength for workable 2D materials and offers perspectives for other strongly coupled vdW materials.
ADVANCED MATERIALS INTERFACES
(2021)
Article
Nanoscience & Nanotechnology
Simon Mellaerts, Ruishen Meng, Mariela Menghini, Valeri Afanasiev, Jin Won Seo, Michel Houssa, Jean-Pierre Locquet
Summary: The research demonstrates that a single atomic layer of V2O3 with a honeycomb-kagome lattice is structurally stable and can exhibit a room-temperature quantum anomalous Hall effect through atomic on-site spin-orbit coupling. Additionally, the study shows that the quantum anomalous Hall system is robust against small deformations and can be supported by a graphene substrate.
NPJ 2D MATERIALS AND APPLICATIONS
(2021)
Article
Chemistry, Physical
C. Pashartis, M. J. van Setten, M. Houssa, G. Pourtois
Summary: The critical dimensions of electronic device patterns have been reduced to a few nanometers due to miniaturization. At this scale, the mechanical integrity of thin films deviates from their bulk material values, causing reliability issues. Understanding these fundamental aspects is crucial for technology advancements.
APPLIED SURFACE SCIENCE
(2022)
Article
Physics, Condensed Matter
Ramasamy Murugesan, Ruishen Meng, Alexander de Volder, Wout Keijers, Ewald Janssens, Joris van de Vondel, Valeri Afanasiev, Michel Houssa
Summary: The interaction between Au (n) (n = 1-6) clusters and graphene is studied. The binding energy between Au (n) and graphene depends on the number of atoms in the cluster and chemisorption rather than physisorption occurs. The electronic properties and transport properties of graphene strongly depend on the size of the Au (n) clusters.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Materials Science, Multidisciplinary
Simon Mellaerts, Jin Won Seo, Valeri Afanas'ev, Michel Houssa, Jean-Pierre Locquet
Summary: Understanding ferroelectricity is important for the development of new materials and manipulations. The recent discovery of supertetragonal (ST) phases with high c/a ratio and outstanding ferroelectric polarization values has led to a need for studying the microscopic origin of these phases. A first-principle study on barium titanate under hydrostatic negative pressure reveals an isosymmetric phase transition to an ST phase, driven by a drastic change in the covalently pi-bonded electrons. These findings provide guidance for finding new ST phases and developing novel multiferroic materials, and can be applied to understanding other isosymmetric phase transitions.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Chemistry, Physical
Ruishen Meng, Lino da Costa Pereira, Jean-Pierre Locquet, Valeri Afanas'ev, Geoffrey Pourtois, Michel Houssa
Summary: Through high-throughput calculations and evolutionary search method, 122 2D materials with potential ferromagnetism upon hole doping are identified, with some materials predicted to have Curie temperatures above 300K. These findings are important for understanding the properties of doped 2D ferromagnetic materials and enriching the family of 2D magnetic materials.
NPJ COMPUTATIONAL MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Elaheh Akhoundi, Michel Houssa, Aryan Afzalian
Summary: We used first-principles calculations and non-equilibrium Green's function to study carrier transport in the edges of topological insulator ribbons. We investigated the effects of electron-phonon interactions on the edge state transport. We found that electron-phonon scattering can lead to the destruction of dissipationless transport in topological insulators with small bulk gaps, but the transport can still be achieved if restricted to the protected states.
SOLID-STATE ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Rutger Duflou, Michel Houssa, Aryan Afzalian
Summary: This article introduces a quantum transport simulation method based on the non-equilibrium Green's function formalism, which requires accurate integration of charges in the system. We demonstrate a full charge integration scheme that incorporates electronic screening effects and interface charges more correctly than the simpler excess charge approach. We show that under certain conditions the two approaches are equivalent, but for devices containing metals, they may demonstrate significantly different behavior.
JOURNAL OF COMPUTATIONAL ELECTRONICS
(2023)
Article
Chemistry, Physical
Elaheh Akhoundi, Michel Houssa, Aryan Afzalian
Summary: Using non-equilibrium Green's function simulations combined with first-principles density functional theory, we investigate the impact of electron-phonon coupling on edge-state transport in two-dimensional topological insulators. We find that the transport in a topological insulator with a small bulk gap, like stanene, is heavily affected by electron-phonon scattering, while bismuthene with a larger bulk gap shows higher immunity to electron-phonon scattering. Finite-size effects in stanene ribbons are also studied to mitigate the negative effects of a small bulk gap. Additionally, topological insulator ribbons are used as materials for field-effect transistors, and the results reveal the potential of manipulating edge states and opening a gap in stanene ribbons.
Article
Nanoscience & Nanotechnology
Rutger Duflou, Geoffrey Pourtois, Michel Houssa, Aryan Afzalian
Summary: Through ab-initio simulation techniques, we investigated the metal contacts for introduction of 2D materials in scaled devices, and found that a low semiconducting-metal contact resistance can be achieved by selecting appropriate 2D metals. We demonstrated that both ohmic or small Schottky barrier top and side contacts can be achieved with a contact resistance below 100 omega mu m. We also performed a screening of possible 2D-3D top contacts and showed that contact resistances below 100 omega mu m can be achieved in certain conditions.
NPJ 2D MATERIALS AND APPLICATIONS
(2023)
Article
Multidisciplinary Sciences
Ruishen Meng, Michel Houssa
Summary: Using spin-polarized first-principles calculations, we investigate the stability, electronic properties, and magnetic behavior induced by hole-doping in 2D PbBr2 and HgBr2. These nonmagnetic materials can exhibit stable ferromagnetic order when hole-doped at high densities. Intrinsic and extrinsic defects, such as vacancies and antisites, affect the hole-doping and subsequent ferromagnetism. Li substituting Pb or Hg, and S replacing Br in 2D HgBr2, are potential dopants that can produce shallow acceptor states and result in stable ferromagnetic order in these dibromides.
SCIENTIFIC REPORTS
(2023)
Article
Nanoscience & Nanotechnology
Pascal Gehring, Clement Merckling, Ruishen Meng, Valentin Fonck, Bart Raes, Michel Houssa, Joris Van de Vondel, Stefan De Gendt
Summary: We synthesized and characterized high-quality thin films of a topological semimetal, and observed strong metallic behavior and spin-orbit coupling in these films through cryogenic magneto-transport experiments. The temperature dependence of the electrical resistance revealed a pronounced Kondo effect, indicating the presence of magnetic scatterers. Density functional theory calculations confirmed that Bi vacancies act as intrinsic magnetic scatterers in this topological semimetal.
Article
Chemistry, Multidisciplinary
Guillaume Libeert, Ramasamy Murugesan, Marton Guba, Wout Keijers, Simon Collienne, Bart Raes, Steven Brems, Stefan De Gendt, Alejandro Silhanek, Tibor Holtzl, Michel Houssa, Joris Van de Vondel, Ewald Janssens
Summary: This paper presents a new method to quantify the energy barriers for adsorption and desorption of gas molecules on few-atom clusters by utilizing reaction-induced changes of the doping level of a graphene substrate. The method is illustrated for oxygen adsorption on Au-3 clusters.
Article
Materials Science, Multidisciplinary
S. Mellaerts, R. Meng, V Afanasiev, J. W. Seo, M. Houssa, J-P Locquet
Summary: Recent experimental success in 2D magnetism has led to a search for new magnetic materials with strong magnetic anisotropy and high Curie temperature. Dirac half-metals (DHMs) are identified as realizations of the Kane-Mele Hubbard model at quarter filling, contributing to a better understanding of these materials and paving the way for the discovery of new DHM systems.
Article
Materials Science, Multidisciplinary
A. S. Fenta, C. O. Amorim, J. N. Goncalves, N. Fortunato, M. B. Barbosa, J. P. Araujo, M. Houssa, S. Cottenier, M. J. Van Bael, J. G. Correia, V. S. Amaral, L. M. C. Pereira
Summary: This study uses density functional theory to investigate the interaction between graphene and Hg adatoms, finding that Hg as isolated adatom is the most stable configuration. Isolated adatoms have minor effect on the electronic structure of graphene, while Hg monolayer configurations induce a metallic state.
JOURNAL OF PHYSICS-MATERIALS
(2021)
