Article
Computer Science, Information Systems
Emilio Perez-Bosch Quesada, Rocio Romero-Zaliz, Eduardo Perez, Mamathamba Kalishettyhalli Mahadevaiah, John Reuben, Markus Andreas Schubert, Francisco Jimenez-Molinos, Juan Bautista Roldan, Christian Wenger
Summary: This work evaluates three different RRAM compact models implemented in Verilog-A to replicate a multilevel approach based on the switching capability of experimental devices. The models are integrated in 1T-1R cells to control their analog behavior using compliance current, with four resistance levels simulated and verified for multilevel capability. Additionally, an Artificial Neural Network study is conducted to assess the viability of the multilevel approach in a real scenario.
Article
Chemistry, Multidisciplinary
Minsu Park, Beomki Jeon, Jongmin Park, Sungjun Kim
Summary: This study introduces a memristor with a composite structure that can mimic the characteristics of a nociceptor, exhibiting stable performance and controllable threshold switching characteristics. This is of great importance for the development of artificial intelligence technology.
Article
Mathematics, Interdisciplinary Applications
D. Maldonado, C. Aguilera-Pedregosa, G. Vinuesa, H. Garcia, S. Duenas, H. Castan, S. Aldana, M. B. Gonzalez, E. Moreno, F. Jimenez-Molinos, F. Campabadal, J. B. Roldan
Summary: An in-depth simulation and experimental study has been conducted to analyze the thermal effects on the variability of resistive memories. It was found that the variability for all analyzed magnitudes was higher at low temperatures. The study used kinetic Monte Carlo simulations to explain this higher variability based on the morphology and density changes of conductive filaments observed at low temperatures.
CHAOS SOLITONS & FRACTALS
(2022)
Article
Engineering, Electrical & Electronic
Wei-Chen Chen, Shengjun Qin, Zhouchangwan Yu, H. -S. Philip Wong
Summary: The insertion of a thin SnO2 layer within the HfO2 switching layer significantly reduces variations in write voltage and read resistance for resistive random access memory. This approach improves the performance and stability of the memory device by decreasing cycle-to-cycle differences and retaining a tight resistance distribution after a large number of pulse cycles. The thin SnO2 acts as an oxygen stopping layer, explaining the origin of reduced variability and showing promise for reducing variability in resistive memory technology.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Wei Zhang, Jianzhang Lei, Yixian Dai, Xuehua Zhang, Limin Kang, Bowen Peng, Fangren Hu
Summary: In this study, the effect of top contact interface and microstructural characteristics of the insulating layers on resistive switching behaviors was investigated. The results show that the interfacial charge migration process plays a key role in the resistive switching process, and the electrode characteristics have a significant impact on the resistive switching performance.
Article
Chemistry, Multidisciplinary
M. Laura Urquiza, Md Mahbubul Islam, Adri C. T. van Duin, Xavier Cartoixa, Alejandro Strachan
Summary: Using molecular dynamics simulations, the atomic processes underlying forming, reset, and set in HfO2-based resistive random access memory (RRAM) cells are characterized. The formation and dissolution of conductive filaments during device operation are tracked with atomic detail. Reset can be achieved through a redox effect or a thermochemical process, while the set process involves lateral oxygen atoms.
Article
Engineering, Electrical & Electronic
N. Arun, S. V. S. Nageswara Rao, A. P. Pathak
Summary: In this paper, the resistive switching characteristics of HfO2-based metal-insulator-metal structures with four different metal bottom electrode materials (Au, Al, Pt, and Cu) are systematically investigated. It is found that Au and Pt have lower set and reset voltages, while Pt has a higher resistance ratio (R-off/R-on) of about 10(5). On the other hand, Al and Cu exhibit multilevel switching during the reset process. The oxygen affinity of the bottom electrode is expected to result in the formation of an interfacial layer with the active (HfO2) layer. Furthermore, the conduction mechanisms in the high resistance state (HRS) curves of these devices are studied, and the dominance of the Poole-Frenkel effect at higher voltages (> 1 V) in the HRS curve is observed.
JOURNAL OF ELECTRONIC MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
E. Salvador, M. B. Gonzalez, F. Campabadal, J. Martin-Martinez, R. Rodriguez, E. Miranda
Summary: This study addresses the inclusion of uncorrelated cycle-to-cycle variability in the LTSpice quasistatic memdiode model for RRAM devices. By analyzing experimental data and incorporating suitable model parameter distributions, Monte Carlo simulations are carried out to compare experimental and simulated observables, with recalculations of model estimands done if necessary. Special emphasis is placed on describing the main difficulties underlying this seemingly simple procedure.
SOLID-STATE ELECTRONICS
(2021)
Article
Materials Science, Multidisciplinary
O. G. Ossorio, G. Vinuesa, H. Garcia, B. Sahelices, S. Duenas, H. Castan, E. Perez, M. K. Mahadevaiah, Ch. Wenger
Summary: The study showed that thin layers of amorphous hafnium oxide are suitable for manufacturing RRAM memories, which are good candidates for replacing flash memories, and exhibit excellent multilevel capabilities and resistive-switching behavior.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2021)
Article
Chemistry, Physical
A. Napolean, N. M. Sivamangai, R. NaveenKumar, N. Nithya
Summary: The study found that devices formed with annealing and high ambient temperature had lower operating voltage, improved uniformity, and reliability compared to devices formed without annealing at low temperature.
Article
Computer Science, Information Systems
Binbin Yang, Daniel Arumi, Salvador Manich, Alvaro Gomez-Pau, Rosa Rodriguez-Montanes, Mireia Bargallo Gonzalez, Francesca Campabadal, Liang Fang
Summary: The proposal suggests associating two serial RRAM devices as a basic cell to store sensitive data, which can address the vulnerability of non-volatile memory cells to adversary attacks. The cell has three states and can effectively protect stored data when the system is powered off or the data is not in use.
Article
Computer Science, Information Systems
Mamathamba Kalishettyhalli Mahadevaiah, Eduardo Perez, Marco Lisker, Markus Andreas Schubert, Emilio Perez-Bosch Quesada, Christian Wenger, Andreas Mai
Summary: In this study, the resistive switching properties of HfO2 based 1T-1R memristive devices were modified by adding ultra-thin layers of Al2O3. Three different types of memristive stacks were fabricated and the switching properties were discussed in terms of forming voltages, low resistance state, high resistance state, and their variabilities. The experimental I-V characteristics of set and reset operations were evaluated using the quantum point contact model, and the properties of the conduction filament in the on and off states were discussed based on the model parameters obtained from the QPC fit.
Article
Engineering, Electrical & Electronic
G. Vinuesa, O. G. Ossorio, H. Garcia, B. Sahelices, H. Castan, S. Duenas, M. Kull, A. Tarre, T. Jogiaas, A. Tamm, A. Kasikov, K. Kukli
Summary: In this paper, the electrical characterization of HfO2:Al2O3 based metal-insulator-metal structures prepared using atomic layer deposition is reported. The study reveals the dependence of electrical behavior on the HfO2:Al2O3 cycle ratio and proposes an explanation for the differences in Resistive Switching properties based on the distribution of HfAlOx layers. The paper also discusses the dependence of Resistive Switching properties on the growth temperature of the samples.
SOLID-STATE ELECTRONICS
(2021)
Article
Oncology
Han Koo, Sangwon Byun, Jieun Seo, Yuri Jung, Dong Chul Lee, Jung Hee Cho, Young Soo Park, Young Il Yeom, Kyung Chan Park
Summary: IGF-1R is commonly overexpressed in solid tumors, but gene amplification is rare. Research shows that PKM2 regulates IGF-1R protein expression by stabilizing the precursor protein through HSP90 binding. Inhibiting PKM2 reduces IGF-1R levels, inhibits AKT activation, and increases apoptotic cell death, suggesting PKM2 as a potential therapeutic target in cancers with dysregulated IGF signaling.
Article
Multidisciplinary Sciences
Hui-Fang Chang, Shih-En Chou, Ji-Yen Cheng
Summary: This study used a microfluidic cell culture system to investigate cell differentiation, finding that simple direct current pulse treatment can control the fate of neural stem and progenitor cells, aiding in the development of therapeutic strategies for nervous system disorders.
JOVE-JOURNAL OF VISUALIZED EXPERIMENTS
(2021)
Article
Computer Science, Information Systems
Rocio Romero-Zaliz, Eduardo Perez, Francisco Jimenez-Molinos, Christian Wenger, Juan B. Roldan
Summary: A comprehensive analysis was conducted on two types of artificial neural networks, revealing that convolutional neural networks (CNN) outperform multilayer perceptrons (MLP) in image recognition processes due to the ability of convolutional layers to extract image features and reduce data complexity.
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
Computer Science, Information Systems
Eduardo Perez, Antonio Javier Perez-avila, Rocio Romero-Zaliz, Mamathamba Kalishettyhalli Mahadevaiah, Emilio Perez-Bosch Quesada, Juan Bautista Roldan, Francisco Jimenez-Molinos, Christian Wenger
Summary: This study implemented truly discrete and linearly spaced conductive levels in RRAM arrays by tuning programming parameters, significantly reducing device-to-device and cycle-to-cycle variability. The optimized parameters improved precision of VMM results and recognition accuracy of neural network by about 6% compared with non-optimized parameters.
Article
Engineering, Electrical & Electronic
Valerio Milo, Artem Glukhov, Eduardo Perez, Cristian Zambelli, Nicola Lepri, Mamathamba Kalishettyhalli Mahadevaiah, Emilio Perez-Bosch Quesada, Piero Olivo, Christian Wenger, Daniele Ielmini
Summary: This study provides a detailed examination of the multilevel-cell programming of RRAM for neural network applications, comparing different programming schemes and discussing their variations in programming characteristics. The research highlights a tradeoff between FC-NN accuracy, size, and current consumption.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Biochemical Research Methods
Sandra Stanke, Christian Wenger, Frank F. Bier, Ralph Hoelzel
Summary: This paper presents a simple and fast method using alternating current electrokinetic forces to immobilize sub-micrometer objects onto nanoelectrode arrays. The influenza virus is chosen as a model organism due to its medical relevance. One of the outstanding features is the ability to permanently immobilize viral material to the electrodes, eliminating the need for prior chemical surface modification. The accumulation of viral material over time is observed using fluorescence microscopy, and the influences of side effects like electrothermal fluid flow are discussed. By combining fluorescence microscopy with deconvolution, it is shown that the viral material is mainly attracted to the electrode edge.
Article
Computer Science, Information Systems
Mamathamba Kalishettyhalli Mahadevaiah, Eduardo Perez, Marco Lisker, Markus Andreas Schubert, Emilio Perez-Bosch Quesada, Christian Wenger, Andreas Mai
Summary: In this study, the resistive switching properties of HfO2 based 1T-1R memristive devices were modified by adding ultra-thin layers of Al2O3. Three different types of memristive stacks were fabricated and the switching properties were discussed in terms of forming voltages, low resistance state, high resistance state, and their variabilities. The experimental I-V characteristics of set and reset operations were evaluated using the quantum point contact model, and the properties of the conduction filament in the on and off states were discussed based on the model parameters obtained from the QPC fit.
Article
Biochemical Research Methods
Mareike Pruefer, Christian Wenger, Frank F. Bier, Eva-Maria Laux, Ralph Hoelzel
Summary: Dielectrophoresis (DEP) is an AC electrokinetic effect used to manipulate cells and immobilize smaller particles. In this study, the activity of the enzyme horseradish peroxidase (HRP) was quantified after immobilization using DEP. The high residual activity of the immobilized enzyme demonstrates the suitability of this method for biosensing and research applications.
Article
Nanoscience & Nanotechnology
Carsten Strobel, Carlos A. Chavarin, Karola Richter, Martin Knaut, Johanna Reif, Sandra Voelkel, Andreas Jahn, Matthias Albert, Christian Wenger, Robert Kirchner, Johann W. Bartha, Thomas Mikolajick
Summary: A graphene-based three-terminal barristor device was proposed to overcome the low on/off ratios and insufficient current saturation of conventional graphene field-effect transistors. This device, called graphene adjustable-barriers transistor (GABT), utilizes a semiconductor-based gate to modulate the device currents and demonstrates high current gain. The functionality of a silicon-graphene-germanium GABT with ultra-high current gain was successfully demonstrated.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Engineering, Electrical & Electronic
Andrea Baroni, Artem Glukhov, Eduardo Perez, Christian Wenger, Daniele Ielmini, Piero Olivo, Cristian Zambelli
Summary: This paper analyzes the benefits of a new programming algorithm in RRAM arrays, which achieves better conductance control and lower variability through Set and Reset operations. The superior performance stability of this algorithm is demonstrated through data retention analysis and artificial neural network simulation.
IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY
(2022)
Article
Chemistry, Multidisciplinary
Max Franck, Jaroslaw Dabrowski, Markus Andreas Schubert, Christian Wenger, Mindaugas Lukosius
Summary: In this study, the growth of hexagonal boron nitride (hBN) on epitaxial Ge(001)/Si substrates using high-vacuum chemical vapor deposition from borazine was systematically investigated for the first time. The research findings suggest that the process pressure and growth temperature have certain influences on the morphology, growth rate, and crystalline quality of hBN films.
Article
Engineering, Electrical & Electronic
Eduardo Perez, David Maldonado, Emilio Perez-Bosch Quesada, Mamathamba K. K. Mahadevaiah, Francisco Jimenez-Molinos, Christian Wenger, Juan B. B. Roldan
Summary: This article investigates four different parameter extraction methods and uses heat maps to statistically analyze experimental data in order to obtain the forming, reset, and set switching voltages in memristive devices. Heat maps provide an overview of the entire data and allow easy detection of inhomogeneities in the fabrication process.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Emilio Perez-Bosch Quesada, Mamathamba Kalishettyhalli Mahadevaiah, Tommaso Rizzi, Jianan Wen, Markus Ulbricht, Milos Krstic, Christian Wenger, Eduardo Perez
Summary: This work focuses on studying the accuracy degradation of consecutive vector-matrix multiplication (VMM) operations and the importance of robustness in hardware systems.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Carsten Strobel, Carlos A. Chavarin, Sandra Voelkel, Andreas Jahn, Andre Hiess, Martin Knaut, Matthias Albert, Christian Wenger, Olaff Steinke, Ulf Stephan, Soeren Roehlecke, Thomas Mikolajick
Summary: The arrival of high-mobility two-dimensional materials like graphene has brought back the vertical semiconductor-metal-semiconductor (SMS) hot electron transistors. With the monolayer thickness of graphene, improved SMS transistors with a semimetallic graphene-base electrode are now possible for high-frequency applications. In this study, a device composed of amorphous silicon, graphene, and crystalline silicon is reported. The device is fabricated by a four-mask lithography process for the first time, leading to significant improvements in device performance. A strongly increased common-emitter current gain of 2% has been achieved, while the on-off ratio improved to 1.6 x 105, surpassing theoretical predictions. Better interface characteristics and decreased lateral dimensions of the devices were the main contributing factors. Based on DC measurements, a cutoff frequency of approximately 26 MHz is expected.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Fatima Akhtar, Jaroslaw Dabrowski, Rasuole Lukose, Christian Wenger, Mindaugas Lukosius
Summary: This study demonstrates the importance of uniform growth in the fabrication of graphene devices by reporting on the growth of large-scale, high-quality monolayer graphene on semiconducting 8-inch Ge(110)/Si wafers using chemical vapor deposition. The quality of graphene is indicated by small FWHM of the Raman 2D band, low intensity ratio of the Raman D and G bands, and homogeneous SEM images. Hall measurements confirm the high mobility and low sheet resistance of the graphene. The difference in growth mechanisms between Ge(001) and Ge(110) is attributed to their unique surface geometries and complex reconstructions.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Engineering, Electrical & Electronic
Tommaso Rizzi, Andrea Baroni, Artem Glukhov, Davide Bertozzi, Christian Wenger, Daniele Ielmini, Cristian Zambelli
Summary: Resistive Random Access Memory (RRAM) technology has the potential to improve FPGA performance, reduce footprint, and lower energy requirements compared to CMOS-based products. However, high programming power consumption and non-ideal behaviors of the RRAM device hinder its integration in FPGAs. This work explores the impact of different programming procedures on run-time performance and highlights the importance of target resistive state selection and programming algorithm in reducing delay and energy metrics and improving robustness against variations.
IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY
(2023)
