Script list Publications
(1) Strategien für wellenlängenselektive Ge-Photodetektoren in 200-mm-Wafer-Siliziumtechnologie
L. Augel, S. Reiter, A. Sengül, Ch. Mai, C.A. Chavarin, P. Oleynik, F. Berkmann, Ch. Wenger, I.A. Fischer
Proc. 11. MikroSystemTechnik Kongress (MST 2025), 180 (2025)
(iCampus II)
(2) Enhancing RRAM Reliability: Exploring the Effects of Al Doping on HfO2-Based Devices
A. Baroni, E. Pérez, K.D.S. Reddy, S. Pechmann, Ch. Wenger, D. Ielmini, C. Zambelli
IEEE Transactions on Device and Materials Reliability 25(3), 379 (2025)
DOI: 10.1109/TDMR.2025.3581061
This study provides a comprehensive evaluation of RRAM devices based on HfO2 and Al-doped HfO2 insulators, focusing on critical performance metrics, including Forming yield, Post-Programming Stability (PPS), Fast Drift, Endurance, and Retention at elevated temperatures (125 ∘C). Aluminum doping significantly enhances device reliability and stability, improving Forming yield, reducing current drift during programming and Retention tests, and minimizing variability during Endurance cycling. While Al5%:HfO2 achieves most of the observed benefits compared to pure HfO2, Al7%:HfO2 offers incremental advantages for scenarios requiring extreme reliability. These findings position Al-doped HfO2 devices as a promising solution for RRAM-based systems in memory and neuromorphic computing, highlighting the potential trade-off between performance gains and increased fabrication complexity. This work underlines the importance of material engineering for optimizing RRAM devices in application-specific contexts.
(3) Comparing Short and Long-Term Reliability of HfO2 and Al:HfO2 RRAM Devices
A. Baroni, E. Pérez, K.D.S. Reddy, S. Pechmann, Ch. Wenger, D. Ielmini, C. Zambelli
Proc. IEEE International Integrated Reliability Workshop (IIRW 2024), (2025)
DOI: 10.1109/IIRW62856.2024.10947134
(4) On-Chip-Brechungsindex-Sensoren in 200-mm-Wafer-Siliziumtechnologie
F. Berkmann, S. Reiter, A. Sengül, Ch. Mai, C.A. Chavarin, Ch. Wenger, I.A. Fischer
Proc. 11. MikroSystemTechnik Kongress (MST 2025), 476 (2025)
(iCampus II)
(5) Evaluating Device Variability in RRAM-Based Single and Multi-Layer Perceptrons
A. Blumenstein, E. Perez, Ch. Wenger, N. Dersch, A. Kloes, B. Iniguez, M. Schwarz
Proc. 32nd International Conference Mixed Design of Integrated Circuits and Systems (MIXDES 2025), abstr. book 33 (2025)
(AVMMSafe)
(6) Evaluating Device Variability in RRAM-Based Single- and Multi-Layer Perceptrons
A. Blumenstein, E. Perez, Ch. Wenger, N. Dersch, A. Kloes, B. Iniguez, M. Schwarz
Proc. 32nd International Conference Mixed Design of Integrated Circuits and Systems (MIXDES 2025), 74 (2025)
DOI: 10.23919/MIXDES66264.2025.11092102, (AVMMSafe)
(7) CMOS-Compatible Ge Metasurface Nanostructures with FTIR-Validated Resonance Optimization
W.-H. Chen, J. Schlipf, G. Capellini, P. Oleynik, D. Ryzhak, Y. Yamamoto, W.-C. Wen, K. Hnida-Gut, Ch. Wenger, I.A. Fischer, O. Skibitzki
Proc. 10th International Symposium on Control of Semiconductor Interfaces (ISCSI-X), the International Conference on Silicon Epitaxy and International SiGe Technology and Device Meeting (ICSI/ISTDM 2025), 205 (2025)
(OASYS)
(8) CW Electrically Pumped GeSn/SiGeSn MQW Lasers
O. Concepción, L. Seidel, T. Liu, G. Capellini, M. Oehme, D. Grützmacher, D. Buca
Proc. IEEE Silicon Photonics Conference (SiPhotonics 2025), ThB6 (2025)
DOI: 10.1109/SiPhotonics64386.2025.10985491
(9) Statistical Model for the Calculation of Conductance Variations of Memristive Devices
N. Dersch, E. Perez, Ch. Wenger, M. Lanza, K. Zhu, M. Schwarz, B. Iniguez, A. Kloes
Proc. 51st IEEE European Solid-State Electronics Research Conference (ESSERC 2025), 373 (2025)
DOI: 10.1109/ESSERC66193.2025.11213973, (AVMMSafe)
(10) A Closed-Form Model for Programming of Oxide-Based Resistive Random Access Memory Cells Derived From the Stanford Model
N. Dersch, E. Perez, Ch. Wenger, M. Schwarz, B. Iniguez, A. Kloes
Solid-State Electronics 230, 109238 (2025)
DOI: 10.1016/j.sse.2025.109238
This paper presents a closed-form model for pulse-based programming of oxide-based resistive random access memory devices. The Stanford model is used as a basis and solved in a closed-form for the programming cycle. A constant temperature is set for this solution. With the closed-form model, the state of the device after programming or the required programming settings for achieving a specific device conductance can be calculated directly and quickly. The Stanford model requires time-consuming iterative calculations for high accuracy in transient analysis, which is not necessary for the closed-form model. The closed-form model is scalable across different programming pulse widths and voltages.
(11) Performance of Pulse-Programmed Memristive Crossbar Array with Bimodally Distributed Stochastic Synaptic Weights
N. Dersch, E. Perez, Ch. Wenger, Ch. Roemer, M. Schwarz, B. Iniguez, A. Kloes
Solid-State Electronics 227, 109128 (2025)
DOI: 10.1016/j.sse.2025.109128, (KI-IoT)
In this paper, we present a method of implementing memristive crossbar arrays with bimodally distributed weights. The bimodal distribution is a result of pulse-based programming. The memristive devices are used for implementing synaptic weights and can only have an ON (logical “1″) or an OFF (logical ”0″) state. The state of the memristive device after programming is determined by the bimodal distribution. The highly efficient noise-based variability approach is used to simulate this stochasticity. The memristive crossbar array is used to classify the MNIST data set and comprises more than 15,000 weights. The interpretation of these weights is investigated. In addition, the influence of the stochasticity of the weights and the accuracy of the weights on the classification results is considered and various programming settings are examined.
(12) CSiGeSn Epitaxy: Future Isovalent Isomorphism in Group-IV Materials
A.J. Devaiya, O. Concepcion, T. Fischer, A. Tiedemann, G. Capellini, S. Mathur, D. Grützmacher, D. Buca
Proc. 16th International Workshop on New Group IV Semiconductor Nanoelectronics (El4GroupIV 2025), 35 (2025)
(13) RISC-V CPU Design using RRAM-CMOS Standard Cells
M. Fritscher, M. Uhlmann, P. Ostrovskyy, D. Reiser, J.-C. Chen, J. Wen, C. Schulze, G. Kahmen, D. Fey, M. Reichenbach, M. Krstic, Ch. Wenger
IEEE Transactions on Very Large Scale Integration (VLSI) Systems 33(9), 2406 (2025)
DOI: 10.1109/TVLSI.2025.3554476, (iCampus II)
The breakdown of Dennard scaling has been the driver for many innovations such as multicore CPUs and has fueled the research into novel devices such as resistive random access memory (RRAM). These devices might be a means to extend the scalability of integrated circuits since they allow for fast and nonvolatile operation. Unfortunately, large analog circuits need to be designed and integrated in order to benefit from these cells, hindering the implementation of large systems. This work elaborates on a novel solution, namely creating digital standard cells utilizing RRAM devices. Albeit this approach can be used both for small gates and large macroblocks we illustrate it for a 2T2R-cell. Since RRAM devices can be vertically stacked with transistors this enables us to construct a NAND standard cell which merely consumes the area of two transistors. This leads to a 25% area reduction compared to an equivalent CMOS NAND gate. We illustrate achievable area savings with a halfadder circuit and integrate this novel cell into a digital standard cell library. A synthesized RISC-V core using RRAM-based cells results in a 10.7% smaller area than the equivalent design using standard CMOS gates.
(14) RISC-V CPU Design using RRAM-CMOS Standard Cells
M. Fritscher, M. Uhlmann, P. Ostrovskyy, D. Reiser, J.-C. Chen, J. Wen, C. Schulze, G. Kahmen, D. Fey, M. Reichenbach, M. Krstic, Ch. Wenger
IEEE Transactions on Very Large Scale Integration (VLSI) Systems 33(9), 2406 (2025)
DOI: 10.1109/TVLSI.2025.3554476, (6G-RIC)
The breakdown of Dennard scaling has been the driver for many innovations such as multicore CPUs and has fueled the research into novel devices such as resistive random access memory (RRAM). These devices might be a means to extend the scalability of integrated circuits since they allow for fast and nonvolatile operation. Unfortunately, large analog circuits need to be designed and integrated in order to benefit from these cells, hindering the implementation of large systems. This work elaborates on a novel solution, namely creating digital standard cells utilizing RRAM devices. Albeit this approach can be used both for small gates and large macroblocks we illustrate it for a 2T2R-cell. Since RRAM devices can be vertically stacked with transistors this enables us to construct a NAND standard cell which merely consumes the area of two transistors. This leads to a 25% area reduction compared to an equivalent CMOS NAND gate. We illustrate achievable area savings with a halfadder circuit and integrate this novel cell into a digital standard cell library. A synthesized RISC-V core using RRAM-based cells results in a 10.7% smaller area than the equivalent design using standard CMOS gates.
(15) RISC-V CPU Design using RRAM-CMOS Standard Cells
M. Fritscher, M. Uhlmann, P. Ostrovskyy, D. Reiser, J.-C. Chen, J. Wen, C. Schulze, G. Kahmen, D. Fey, M. Reichenbach, M. Krstic, Ch. Wenger
IEEE Transactions on Very Large Scale Integration (VLSI) Systems 33(9), 2406 (2025)
DOI: 10.1109/TVLSI.2025.3554476, (HYB-RISC)
The breakdown of Dennard scaling has been the driver for many innovations such as multicore CPUs and has fueled the research into novel devices such as resistive random access memory (RRAM). These devices might be a means to extend the scalability of integrated circuits since they allow for fast and nonvolatile operation. Unfortunately, large analog circuits need to be designed and integrated in order to benefit from these cells, hindering the implementation of large systems. This work elaborates on a novel solution, namely creating digital standard cells utilizing RRAM devices. Albeit this approach can be used both for small gates and large macroblocks we illustrate it for a 2T2R-cell. Since RRAM devices can be vertically stacked with transistors this enables us to construct a NAND standard cell which merely consumes the area of two transistors. This leads to a 25% area reduction compared to an equivalent CMOS NAND gate. We illustrate achievable area savings with a halfadder circuit and integrate this novel cell into a digital standard cell library. A synthesized RISC-V core using RRAM-based cells results in a 10.7% smaller area than the equivalent design using standard CMOS gates.
(16) Sensing of Hemin Binding to Albumin using Ge-based Plasmonic Antennas Operating in the THz Range
E. Hardt, R. Varricchio, C.A. Chavarin, G. De Simone, O. Skibitzki, P. Ascenzi, A. di Masi, G. Capellini
IEEE Sensors Journal 25(8), 12881 (2025)
DOI: 10.1109/JSEN.2025.3545736, (IHP- Roma Tre University Joint Lab)
Albumin-based biofunctionalized biosensors have the potential to be utilized for the detection of physiological ligands (e.g., heme) and of pathogenic proteins. In human cells, heme is always bound to proteins due to its toxic nature. However, free heme can be present within tissue and in the bloodstream as a consequence of hemolysis or under pathological conditions like malaria or sickle cell anemia. Therefore, the development of an albumin-based heme biosensor could be relevant from a biomedical viewpoint. In this study, we developed a protein-sensing platform by immobilizing albumin on CMOS-compatible Ge-based THz plasmonic antennas via drop-cast biofunctionalization. To set up the biosensor, the sensing platform was used to quantitatively measure the binding of hemin, a well-known physiological ligand of albumin. This measurement was performed using THz time-domain spectroscopy in dichroic transmission mode, achieving a sensitivity of approximately ~ 200 GHz/mM of the HSA:hemin complex. These preliminary results support the use of CMOS-compatible Ge-based THz plasmonic antennas as innovative sensors that could be monolithically integrated with conventional electronics for storage, processing, and communication into an all-in-one system.
(17) Sensing of Hemin Binding to Albumin using Ge-based Plasmonic Antennas Operating in the THz Range
E. Hardt, R. Varricchio, C.A. Chavarin, G. De Simone, O. Skibitzki, P. Ascenzi, A. di Masi, G. Capellini
IEEE Sensors Journal 25(8), 12881 (2025)
DOI: 10.1109/JSEN.2025.3545736, (iCampus II)
Albumin-based biofunctionalized biosensors have the potential to be utilized for the detection of physiological ligands (e.g., heme) and of pathogenic proteins. In human cells, heme is always bound to proteins due to its toxic nature. However, free heme can be present within tissue and in the bloodstream as a consequence of hemolysis or under pathological conditions like malaria or sickle cell anemia. Therefore, the development of an albumin-based heme biosensor could be relevant from a biomedical viewpoint. In this study, we developed a protein-sensing platform by immobilizing albumin on CMOS-compatible Ge-based THz plasmonic antennas via drop-cast biofunctionalization. To set up the biosensor, the sensing platform was used to quantitatively measure the binding of hemin, a well-known physiological ligand of albumin. This measurement was performed using THz time-domain spectroscopy in dichroic transmission mode, achieving a sensitivity of approximately ~ 200 GHz/mM of the HSA:hemin complex. These preliminary results support the use of CMOS-compatible Ge-based THz plasmonic antennas as innovative sensors that could be monolithically integrated with conventional electronics for storage, processing, and communication into an all-in-one system.
(18) Broadband Light Emission from GaAsP and GaInP Islands Grown on Silicon Nanotips Wafer via Nanoheteroepitaxy
N. Kafi, A. Rodrigues, I. Häusler, H. Ma, C. Netzel, A. Hammud, O. Skibitzki, M. Schmidbauer, F. Hatami
Applied Physics Letters 127(19), 191106 (2025)
DOI: 10.1063/5.0285546, (NHEQuanLEA)
We present the monolithic integration of GaAsxP1−x and GaxIn1−xP islands, selectively grown on a Si(001) nanotip wafer using gas-source molecular-beam epitaxy via a nanoheteroepitaxy approach. Optimal growth temperatures balancing selectivity and compositional control are 520–580 °C for GaAsP and 500–510 °C for GaInP. By adjusting the group III and V fluxes, island luminescence is tuned across a broad spectral range from 1.5 to 2.1 eV. High-resolution x-ray diffraction measurements on ensembles exceeding one million islands confirm that both GaAsP and GaInP islands are relaxed, while broad diffraction linewidths point to alloy fluctuations. Scanning transmission electron microscopy combined with energy-dispersive x-ray spectroscopy reveals compositional variations of up to 6% among the GaAsP islands, with nearly uniform composition within individual islands. In the case of GaInP, indium-rich regions are observed within single islands, with up to 11% variation across the ensemble. These compositional variations result in broadened or multiple luminescence peaks. Despite challenges in achieving full uniformity, this work demonstrates an alternative pathway for the monolithic integration of scalable III–V infrared-to-visible light emitters and detectors on silicon, advancing the development of microscale light sources for the silicon platform.
(19) Character Recognition Application of a Neural Circuit Including Lateral Inhibitory Mechanisms
D. Llobet Muñoz, I.K. Chatzipaschalis, A. Calomarde, A. Rubio
Proc. 40th Conference on Design of Circuits and Integrated Systems (DCIS 2025), 108 (2025)
DOI: 10.1109/DCIS67520.2025.11281935
(20) A Comprehensive Statistical Study of the Post-Programming Conductance Drift in HfO2-based Memristive Devices
D. Maldonado, C. Acal, H. Ortiz, A.M. Aguilera, J.E. Ruiz-Castro, A. Cantudo, A. Baroni, K.D.S. Reddy, S. Pechmann, M. Uhlmann, Ch. Wenger, E. Perez, J.B. Roldan
Materials Science in Semiconductor Processing 196, 109668 (2025)
DOI: 10.1016/j.mssp.2025.109668, (KI-IoT)
(21) Effects of the Compliance Current on the Switching of HfO2 and Al:HfO2 Memristive Devices: Characterization and Modeling
D. Maldonado, K.D.S. Reddy, S. Pechmann, Ch. Wenger, J.B. Roldán, E. Pérez
Proc. 15th Spanish Conference on Electron Devices (CDE 2025), (2025)
DOI: 10.1109/CDE66381.2025.11038898, (KI-IoT)
(22) A Statistical and Modeling Study on the Effects of Radiation on Au/Ta/ZrO2(Y)/Pt/Ti Memristive Devices
D. Maldonado, A. Cantudo, D.V. Guseinov, M.N. Koryazhkina, E.V. Okulich, D.I. Tetelbaum, N.O. Bartev, N.G. Danchenko, V.A. Pikar, A.V. Teterevkov, F. Jiménez-Molinos, A.N. Mikhaylov, J.B. Roldán
Chaos, Solitons & Fractals 191, 115909 (2025)
DOI: 10.1016/j.chaos.2024.115909
In this study we have investigated the impact of radiation on the performance and reliability of Au/Ta/ZrO2(Y)/Pt/Ti memristive devices, with a particular focus on understanding the changes induced by ion irradiation. A comprehensive experimental approach was employed, involving irradiation with various ion species, including H⁺, Ne⁺, O⁺, and Kr⁺ to simulate different radiation environments. Thus, advanced statistical and modeling techniques to analyze the effects of irradiation on the resistive switching (RS) characteristics of the devices have been employed. Results revealed significant alterations in the RS parameters post-irradiation, including set and reset voltages and currents. These changes were found to vary depending on the ion species and dosage, with heavier ions such as Kr⁺ causing more pronounced effects. The findings are supported by detailed Monte Carlo simulations, which provided insights into the distribution of vacancies within the memristive devices under neutron irradiation. The experimental data, combined with the modeling results, indicate that ion irradiation can lead to the formation of defect structures that critically affect the performance of memristive devices.
(23) Dependable Neuromorphic Computing-in-Memory Architectures
F. Merchant, A. Bende, M. Fritscher, S. Kvatinsky, S. Singh, V. Rana, R. Dittmann, K.D.S. Reddy, Ch. Wenger, F. Mir, M. Taouil, M. Dev Gomony, S. Hamdioui, H. Corporaal
Proc. 30th IEEE European Test Symposium (ETS 2025), (2025)
DOI: 10.1109/ETS63895.2025.11049617, (HYB-RISC)
(24) Hydrogen Sensing via Heterolytic H2 Activation at Room Temperature by Atomic Layer Deposited Ceria
C. Morales, R. Tschammer, E. Pozarowska, J. Kosto, I.J. Villar-Garcia, V. Pérez-Dieste, M. Favaro, D. Starr, P. Kapuscik, M. Mazur, D. Wojcieszak, J. Domaradzki, C.A. Chavarin, Ch. Wenger, K. Henkel, J.I. Flege
ChemSusChem 18(13), e202402342 (2025)
DOI: 10.1002/cssc.202402342, (iCampus II)
Ultrathin atomic layer deposited ceria films (< 20 nm) are capable of H2 heterolytic activation at room temperature, undergoing a significant reduction regardless of the absolute pressure, as measured under in-situ conditions by near ambient pressure X-ray photoelectron spectroscopy. ALD-ceria can gradually reduce as a function of H2 concentration under H2/O2 environments, especially for diluted mixtures below 10%. At room temperature, this reduction is limited to the surface region, where the hydroxylation of the ceria surface induces a charge transfer towards the ceria matrix, reducing Ce4+ cations to Ce3+. Thus, ALD-ceria replicates the expected sensing mechanism of metal oxides at low temperatures without using any noble metal decorating the oxide surface to enhance H2 dissociation. The intrinsic defects of the ALD deposit seem to play a crucial role since the post-annealing process capable of healing these defects leads to decreased film reactivity. The sensing behavior was successfully demonstrated in sensor test structures by resistance changes towards low concentrations of H2 at low operating temperatures without using noble metals. These promising results call for combining ALD-ceria with more conductive metal oxides, taking advantage of the charge transfer at the interface and thus modifying the depletion layer formed at the heterojunction.
(25) Bottom-Up Strategy to Develop Ultrathin Active Layers by Atomic Layer Deposition for Room Temperature Hydrogen Sensors
C. Morales, R. Tschammer, D. Guttmann, K. Henkel, J.I. Flege, C. Ruffert, C.A. Chavarin, Ch. Wenger,
Proc. 11. MikroSystemTechnik Kongress (MST 2025), 71 (2025)
(iCampus II)
(26) In Situ X-Ray Photoelectron Spectroscopy Study of Atomic Layer Deposited Cerium Oxide on SiO2: Substrate Influence on the Reaction Mechanism During the Early Stages of Growth
C. Morales, M. Gertig, M. Kot, C.A. Chavarin, M.A. Schubert, M.H. Zoellner, Ch. Wenger, K. Henkel, J.I. Flege
Advanced Materials Interfaces 12(5), 2400537 (2024)
DOI: 10.1002/admi.202400537, (iCampus II)
Thermal atomic layer deposition (ALD) of cerium oxide using commercial Ce(thd)4 precursor and O3 on SiO2 substrates is studied employing in-situ X-ray photoelectron spectroscopy (XPS). The system presents a complex growth behavior determined by the change in the reaction mechanism when the precursor interacts with the substrate or the cerium oxide surface. During the first growth stage, non-ALD side reactions promoted by the substrate affect the growth per cycle, the amount of carbon residue on the surface, and the oxidation degree of cerium oxide. On the contrary, the second growth stage is characterized by a constant growth per cycle in good agreement with the literature, low carbon residues, and almost fully oxidized cerium oxide films. This distinction between two growth regimes is not unique to the CeOx/SiO2 system but can be generalized to other metal oxide substrates. Furthermore, the film growth deviates from the ideal layer-by-layer mode, forming micrometric inhomogeneous and defective flakes that eventually coalesce for deposit thicknesses above 10 nm. The ALD-cerium oxide films present less order and a higher density of defects than films grown by physical vapor deposition techniques, likely affecting their reactivity in oxidizing and reducing conditions.
(27) Effects of Temperature and Light on CeO2/SnO2 Thin-Film Hydrogen Sensors
A. Mudundi, A. Kalra, R. Tschammer, C. Morales, J.I. Flege, I.A. Fischer, C.A. Chavarin, Ch. Wenger
Proc. 11. MikroSystemTechnik Kongress (MST 2025), 20 (2025)
(iCampus II)
(28) Cryogenic Characterization of HfO₂-Based RRAM: Exploring Multilevel Switching from 300 K to 1.5 K for Neuromorphic Quantum Computing
E. Perez-Bosch Quesada, A. Mistroni, R. Jia, K.D.S. Reddy, M. Fritscher, F. Reichmann, H. Castan, S. Dueñas, Ch. Wenger, E. Perez
Proc. 57th International Conference on Solid State Devices and Materials (SSDM 2025), 703 (2025)
(INSEKT)
(29) Impact of the Series Resistance on Switching Characteristics of 1T1R HfO2-based RRAM Devices
E. Perez, D. Maldonado, S. Pechmann, K.D.S. Reddy, M. Uhlmann, A. Hagelauer, J.B. Roldan, Ch. Wenger
Proc. 15th Spanish Conference on Electron Devices (CDE 2025), (2025)
DOI: 10.1109/CDE66381.2025.11038868, (KI-IoT)
(30) Analytical Model for Parasitic Resistances of Crossbar Arrays Suitable for Open-Loop Programming Schemes Reliability Analysis
T. Rizzi, T. Zanotti, N. Lepri, E. Pérez, F.M. Puglisi, D. Ielmini, C. Zambelli
Proc. IEEE International Integrated Reliability Workshop (IIRW 2024), (2025)
DOI: 10.1109/IIRW62856.2024.10947147, (HYB-RISC)
(31) Monolithically Integrated GaAs Nanoislands on CMOS-Compatible Si Nanotips using GS-MBE
A. Rodrigues, A. Kamath, H. Illner, N. Kafi, O. Skibitzki, M. Schmidbauer, F. Hatami
Nanomaterials (MDPI) 15(14), 1083 (2025)
DOI: 10.3390/nano15141083, (NHEQuanLEA)
The monolithic integration of III-V semiconductors with silicon (Si) is a critical step toward advancing optoelectronic and photonic devices. In this work, we present GaAs nanoheteroepitaxy (NHE) on Si nanotips using gas-source molecular beam epitaxy (GS-MBE). We discuss the selective growth of fully relaxed GaAs nanoislands on complementary metal oxide semiconductor (CMOS)-compatible Si(001) nanotip wafers. Nanotip wafers were fabricated using a state-of-the-art 0.13 μm SiGe Bipolar CMOS pilot line on 200 mm wafers. Our investigation focuses on understanding the influence of the growth conditions on the morphology, crystalline structure, and defect formation of the GaAs islands. The morphological, structural, and optical properties of the GaAs islands were characterized using scanning electron microscopy, high-resolution X-ray diffraction, and photoluminescence spectroscopy. For samples with less deposition, the GaAs islands exhibit a monomodal size distribution, with an average effective diameter ranging between 100 and 280 nm. These islands display four distinct facet orientations corresponding to the {001} planes. As the deposition increases, larger islands with multiple crystallographic facets emerge, accompanied by a transition from a monomodal to a bimodal growth mode. Single twinning is observed in all samples. However, with increasing deposition, not only a bimodal size distribution occurs, but also the volume fraction of the twinned material increases significantly. These findings shed light on the growth dynamics of nanoheteroepitaxial GaAs and contribute to ongoing efforts toward CMOS-compatible Si-based nanophotonic technologies.
(32) Investigation of Dislocations Introduced in Si Wafer During Flash Lamp Annealing by Photoluminescence Spectroscopy
D. Ryzhak, G. Kissinger, A. Ehlert, A. Sattler, D. Spirito, D. Kot
Physica Status Solidi A 222(8), 2400753 (2025)
DOI: 10.1002/pssa.202400753, (Siltronic Project)
Dislocations are generated in Si wafers during flash lamp annealing for 20 ms. The samples have been etched to different depths and macro-photoluminescence (PL) spectra have been recorded for different dislocation densities. A micro-PL investigation is also carried out on a cross section of a sample. Four characteristic emission peaks are found, which are the well-known D1, D2, D3, and D4 lines. The findings demonstrate a significant influence of the defect densities on the PL spectra of the D lines by using both the micro- and the macro-PL setups, and show a correlation of the PL intensities with etch pit density measured against the depth of the wafer. Additionally, the D lines dependency on temperature is explored, offering insights into the underlying mechanisms. The D lines exhibit a pronounced temperature dependence, which can be attributed to various factors including phonon interactions and thermal expansion effects. The influence of nickel contamination is also examined.
(33) Photoluminescence Enhancement in Germanium All-Dielectric Metasurfaces
J. Schlipf, D. Ryzhak, P. Oleynik, G. Capellini, Y. Yamamoto, O. Skibitzki, I.A. Fischer
Proc. 10th International Symposium on Control of Semiconductor Interfaces (ISCSI-X), the International Conference on Silicon Epitaxy and International SiGe Technology and Device Meeting (ICSI/ISTDM 2025), 177 (2025)
(OASYS)
(34) Photoluminescence Enhancement in Germanium All-Dielectric Metasurfaces
J. Schlipf, D. Ryzhak, P. Oleynik, G. Capellini, Y. Yamamoto, O. Skibitzki, I.A. Fischer
Proc. 10th International Symposium on Control of Semiconductor Interfaces (ISCSI-X), the International Conference on Silicon Epitaxy and International SiGe Technology and Device Meeting (ICSI/ISTDM 2025), 177 (2025)
(iCampus II)
(35) AI-Driven Model for Optimized Pulse Programming of Memristive Devices
B. Spetzler, M. Fritscher, S. Park, N. Kim, Ch. Wenger, M. Ziegler
APL Machine Learning 3(2), 026103 (2025)
DOI: 10.1063/5.0251113, (DI-SIGN-HEP)
Next-generation artificial intelligence (AI) hardware based on memristive devices offers a promising approach to reducing the increasingly large energy consumption of AI applications. However, programming memristive AI hardware to achieve a desired synaptic weight configuration remains challenging because it requires accurate and energy-efficient algorithms for selecting the optimal weight-update pulses. Here, we present a computationally efficient AI model for predicting the weight update of memristive devices and guiding device programming. The synaptic weight-update behavior of bilayer HfO2/TiO2 memristive devices is characterized over a range of pulse parameters to provide experimental data for the AI model. Three different artificial neural network (ANN) configurations are trained and evaluated regarding the amount of training data required for accurate predictions and the computational costs. Finally, we apply the model to an antipulse weight-update process to demonstrate its performance. The results show that accurate and computationally inexpensive predictions are possible with comparatively few datasets and small ANNs. The normalized weight-update processes are predicted with accuracies comparable with larger model architectures but require only 896 floating point operations and 8.33 nJ per inference. This makes the model a promising candidate for integration into AI-driven device controllers as a precise and energy-efficient solution for memristive device programming.
(36) AI-Driven Model for Optimized Pulse Programming of Memristive Devices
B. Spetzler, M. Fritscher, S. Park, N. Kim, Ch. Wenger, M. Ziegler
APL Machine Learning 3(2), 026103 (2025)
DOI: 10.1063/5.0251113, (HYB-RISC)
Next-generation artificial intelligence (AI) hardware based on memristive devices offers a promising approach to reducing the increasingly large energy consumption of AI applications. However, programming memristive AI hardware to achieve a desired synaptic weight configuration remains challenging because it requires accurate and energy-efficient algorithms for selecting the optimal weight-update pulses. Here, we present a computationally efficient AI model for predicting the weight update of memristive devices and guiding device programming. The synaptic weight-update behavior of bilayer HfO2/TiO2 memristive devices is characterized over a range of pulse parameters to provide experimental data for the AI model. Three different artificial neural network (ANN) configurations are trained and evaluated regarding the amount of training data required for accurate predictions and the computational costs. Finally, we apply the model to an antipulse weight-update process to demonstrate its performance. The results show that accurate and computationally inexpensive predictions are possible with comparatively few datasets and small ANNs. The normalized weight-update processes are predicted with accuracies comparable with larger model architectures but require only 896 floating point operations and 8.33 nJ per inference. This makes the model a promising candidate for integration into AI-driven device controllers as a precise and energy-efficient solution for memristive device programming.
(37) AI-Driven Model for Optimized Pulse Programming of Memristive Devices
B. Spetzler, M. Fritscher, S. Park, N. Kim, Ch. Wenger, M. Ziegler
APL Machine Learning 3(2), 026103 (2025)
DOI: 10.1063/5.0251113, (6G-RIC)
Next-generation artificial intelligence (AI) hardware based on memristive devices offers a promising approach to reducing the increasingly large energy consumption of AI applications. However, programming memristive AI hardware to achieve a desired synaptic weight configuration remains challenging because it requires accurate and energy-efficient algorithms for selecting the optimal weight-update pulses. Here, we present a computationally efficient AI model for predicting the weight update of memristive devices and guiding device programming. The synaptic weight-update behavior of bilayer HfO2/TiO2 memristive devices is characterized over a range of pulse parameters to provide experimental data for the AI model. Three different artificial neural network (ANN) configurations are trained and evaluated regarding the amount of training data required for accurate predictions and the computational costs. Finally, we apply the model to an antipulse weight-update process to demonstrate its performance. The results show that accurate and computationally inexpensive predictions are possible with comparatively few datasets and small ANNs. The normalized weight-update processes are predicted with accuracies comparable with larger model architectures but require only 896 floating point operations and 8.33 nJ per inference. This makes the model a promising candidate for integration into AI-driven device controllers as a precise and energy-efficient solution for memristive device programming.
L. Augel, S. Reiter, A. Sengül, Ch. Mai, C.A. Chavarin, P. Oleynik, F. Berkmann, Ch. Wenger, I.A. Fischer
Proc. 11. MikroSystemTechnik Kongress (MST 2025), 180 (2025)
(iCampus II)
(2) Enhancing RRAM Reliability: Exploring the Effects of Al Doping on HfO2-Based Devices
A. Baroni, E. Pérez, K.D.S. Reddy, S. Pechmann, Ch. Wenger, D. Ielmini, C. Zambelli
IEEE Transactions on Device and Materials Reliability 25(3), 379 (2025)
DOI: 10.1109/TDMR.2025.3581061
This study provides a comprehensive evaluation of RRAM devices based on HfO2 and Al-doped HfO2 insulators, focusing on critical performance metrics, including Forming yield, Post-Programming Stability (PPS), Fast Drift, Endurance, and Retention at elevated temperatures (125 ∘C). Aluminum doping significantly enhances device reliability and stability, improving Forming yield, reducing current drift during programming and Retention tests, and minimizing variability during Endurance cycling. While Al5%:HfO2 achieves most of the observed benefits compared to pure HfO2, Al7%:HfO2 offers incremental advantages for scenarios requiring extreme reliability. These findings position Al-doped HfO2 devices as a promising solution for RRAM-based systems in memory and neuromorphic computing, highlighting the potential trade-off between performance gains and increased fabrication complexity. This work underlines the importance of material engineering for optimizing RRAM devices in application-specific contexts.
(3) Comparing Short and Long-Term Reliability of HfO2 and Al:HfO2 RRAM Devices
A. Baroni, E. Pérez, K.D.S. Reddy, S. Pechmann, Ch. Wenger, D. Ielmini, C. Zambelli
Proc. IEEE International Integrated Reliability Workshop (IIRW 2024), (2025)
DOI: 10.1109/IIRW62856.2024.10947134
(4) On-Chip-Brechungsindex-Sensoren in 200-mm-Wafer-Siliziumtechnologie
F. Berkmann, S. Reiter, A. Sengül, Ch. Mai, C.A. Chavarin, Ch. Wenger, I.A. Fischer
Proc. 11. MikroSystemTechnik Kongress (MST 2025), 476 (2025)
(iCampus II)
(5) Evaluating Device Variability in RRAM-Based Single and Multi-Layer Perceptrons
A. Blumenstein, E. Perez, Ch. Wenger, N. Dersch, A. Kloes, B. Iniguez, M. Schwarz
Proc. 32nd International Conference Mixed Design of Integrated Circuits and Systems (MIXDES 2025), abstr. book 33 (2025)
(AVMMSafe)
(6) Evaluating Device Variability in RRAM-Based Single- and Multi-Layer Perceptrons
A. Blumenstein, E. Perez, Ch. Wenger, N. Dersch, A. Kloes, B. Iniguez, M. Schwarz
Proc. 32nd International Conference Mixed Design of Integrated Circuits and Systems (MIXDES 2025), 74 (2025)
DOI: 10.23919/MIXDES66264.2025.11092102, (AVMMSafe)
(7) CMOS-Compatible Ge Metasurface Nanostructures with FTIR-Validated Resonance Optimization
W.-H. Chen, J. Schlipf, G. Capellini, P. Oleynik, D. Ryzhak, Y. Yamamoto, W.-C. Wen, K. Hnida-Gut, Ch. Wenger, I.A. Fischer, O. Skibitzki
Proc. 10th International Symposium on Control of Semiconductor Interfaces (ISCSI-X), the International Conference on Silicon Epitaxy and International SiGe Technology and Device Meeting (ICSI/ISTDM 2025), 205 (2025)
(OASYS)
(8) CW Electrically Pumped GeSn/SiGeSn MQW Lasers
O. Concepción, L. Seidel, T. Liu, G. Capellini, M. Oehme, D. Grützmacher, D. Buca
Proc. IEEE Silicon Photonics Conference (SiPhotonics 2025), ThB6 (2025)
DOI: 10.1109/SiPhotonics64386.2025.10985491
(9) Statistical Model for the Calculation of Conductance Variations of Memristive Devices
N. Dersch, E. Perez, Ch. Wenger, M. Lanza, K. Zhu, M. Schwarz, B. Iniguez, A. Kloes
Proc. 51st IEEE European Solid-State Electronics Research Conference (ESSERC 2025), 373 (2025)
DOI: 10.1109/ESSERC66193.2025.11213973, (AVMMSafe)
(10) A Closed-Form Model for Programming of Oxide-Based Resistive Random Access Memory Cells Derived From the Stanford Model
N. Dersch, E. Perez, Ch. Wenger, M. Schwarz, B. Iniguez, A. Kloes
Solid-State Electronics 230, 109238 (2025)
DOI: 10.1016/j.sse.2025.109238
This paper presents a closed-form model for pulse-based programming of oxide-based resistive random access memory devices. The Stanford model is used as a basis and solved in a closed-form for the programming cycle. A constant temperature is set for this solution. With the closed-form model, the state of the device after programming or the required programming settings for achieving a specific device conductance can be calculated directly and quickly. The Stanford model requires time-consuming iterative calculations for high accuracy in transient analysis, which is not necessary for the closed-form model. The closed-form model is scalable across different programming pulse widths and voltages.
(11) Performance of Pulse-Programmed Memristive Crossbar Array with Bimodally Distributed Stochastic Synaptic Weights
N. Dersch, E. Perez, Ch. Wenger, Ch. Roemer, M. Schwarz, B. Iniguez, A. Kloes
Solid-State Electronics 227, 109128 (2025)
DOI: 10.1016/j.sse.2025.109128, (KI-IoT)
In this paper, we present a method of implementing memristive crossbar arrays with bimodally distributed weights. The bimodal distribution is a result of pulse-based programming. The memristive devices are used for implementing synaptic weights and can only have an ON (logical “1″) or an OFF (logical ”0″) state. The state of the memristive device after programming is determined by the bimodal distribution. The highly efficient noise-based variability approach is used to simulate this stochasticity. The memristive crossbar array is used to classify the MNIST data set and comprises more than 15,000 weights. The interpretation of these weights is investigated. In addition, the influence of the stochasticity of the weights and the accuracy of the weights on the classification results is considered and various programming settings are examined.
(12) CSiGeSn Epitaxy: Future Isovalent Isomorphism in Group-IV Materials
A.J. Devaiya, O. Concepcion, T. Fischer, A. Tiedemann, G. Capellini, S. Mathur, D. Grützmacher, D. Buca
Proc. 16th International Workshop on New Group IV Semiconductor Nanoelectronics (El4GroupIV 2025), 35 (2025)
(13) RISC-V CPU Design using RRAM-CMOS Standard Cells
M. Fritscher, M. Uhlmann, P. Ostrovskyy, D. Reiser, J.-C. Chen, J. Wen, C. Schulze, G. Kahmen, D. Fey, M. Reichenbach, M. Krstic, Ch. Wenger
IEEE Transactions on Very Large Scale Integration (VLSI) Systems 33(9), 2406 (2025)
DOI: 10.1109/TVLSI.2025.3554476, (iCampus II)
The breakdown of Dennard scaling has been the driver for many innovations such as multicore CPUs and has fueled the research into novel devices such as resistive random access memory (RRAM). These devices might be a means to extend the scalability of integrated circuits since they allow for fast and nonvolatile operation. Unfortunately, large analog circuits need to be designed and integrated in order to benefit from these cells, hindering the implementation of large systems. This work elaborates on a novel solution, namely creating digital standard cells utilizing RRAM devices. Albeit this approach can be used both for small gates and large macroblocks we illustrate it for a 2T2R-cell. Since RRAM devices can be vertically stacked with transistors this enables us to construct a NAND standard cell which merely consumes the area of two transistors. This leads to a 25% area reduction compared to an equivalent CMOS NAND gate. We illustrate achievable area savings with a halfadder circuit and integrate this novel cell into a digital standard cell library. A synthesized RISC-V core using RRAM-based cells results in a 10.7% smaller area than the equivalent design using standard CMOS gates.
(14) RISC-V CPU Design using RRAM-CMOS Standard Cells
M. Fritscher, M. Uhlmann, P. Ostrovskyy, D. Reiser, J.-C. Chen, J. Wen, C. Schulze, G. Kahmen, D. Fey, M. Reichenbach, M. Krstic, Ch. Wenger
IEEE Transactions on Very Large Scale Integration (VLSI) Systems 33(9), 2406 (2025)
DOI: 10.1109/TVLSI.2025.3554476, (6G-RIC)
The breakdown of Dennard scaling has been the driver for many innovations such as multicore CPUs and has fueled the research into novel devices such as resistive random access memory (RRAM). These devices might be a means to extend the scalability of integrated circuits since they allow for fast and nonvolatile operation. Unfortunately, large analog circuits need to be designed and integrated in order to benefit from these cells, hindering the implementation of large systems. This work elaborates on a novel solution, namely creating digital standard cells utilizing RRAM devices. Albeit this approach can be used both for small gates and large macroblocks we illustrate it for a 2T2R-cell. Since RRAM devices can be vertically stacked with transistors this enables us to construct a NAND standard cell which merely consumes the area of two transistors. This leads to a 25% area reduction compared to an equivalent CMOS NAND gate. We illustrate achievable area savings with a halfadder circuit and integrate this novel cell into a digital standard cell library. A synthesized RISC-V core using RRAM-based cells results in a 10.7% smaller area than the equivalent design using standard CMOS gates.
(15) RISC-V CPU Design using RRAM-CMOS Standard Cells
M. Fritscher, M. Uhlmann, P. Ostrovskyy, D. Reiser, J.-C. Chen, J. Wen, C. Schulze, G. Kahmen, D. Fey, M. Reichenbach, M. Krstic, Ch. Wenger
IEEE Transactions on Very Large Scale Integration (VLSI) Systems 33(9), 2406 (2025)
DOI: 10.1109/TVLSI.2025.3554476, (HYB-RISC)
The breakdown of Dennard scaling has been the driver for many innovations such as multicore CPUs and has fueled the research into novel devices such as resistive random access memory (RRAM). These devices might be a means to extend the scalability of integrated circuits since they allow for fast and nonvolatile operation. Unfortunately, large analog circuits need to be designed and integrated in order to benefit from these cells, hindering the implementation of large systems. This work elaborates on a novel solution, namely creating digital standard cells utilizing RRAM devices. Albeit this approach can be used both for small gates and large macroblocks we illustrate it for a 2T2R-cell. Since RRAM devices can be vertically stacked with transistors this enables us to construct a NAND standard cell which merely consumes the area of two transistors. This leads to a 25% area reduction compared to an equivalent CMOS NAND gate. We illustrate achievable area savings with a halfadder circuit and integrate this novel cell into a digital standard cell library. A synthesized RISC-V core using RRAM-based cells results in a 10.7% smaller area than the equivalent design using standard CMOS gates.
(16) Sensing of Hemin Binding to Albumin using Ge-based Plasmonic Antennas Operating in the THz Range
E. Hardt, R. Varricchio, C.A. Chavarin, G. De Simone, O. Skibitzki, P. Ascenzi, A. di Masi, G. Capellini
IEEE Sensors Journal 25(8), 12881 (2025)
DOI: 10.1109/JSEN.2025.3545736, (IHP- Roma Tre University Joint Lab)
Albumin-based biofunctionalized biosensors have the potential to be utilized for the detection of physiological ligands (e.g., heme) and of pathogenic proteins. In human cells, heme is always bound to proteins due to its toxic nature. However, free heme can be present within tissue and in the bloodstream as a consequence of hemolysis or under pathological conditions like malaria or sickle cell anemia. Therefore, the development of an albumin-based heme biosensor could be relevant from a biomedical viewpoint. In this study, we developed a protein-sensing platform by immobilizing albumin on CMOS-compatible Ge-based THz plasmonic antennas via drop-cast biofunctionalization. To set up the biosensor, the sensing platform was used to quantitatively measure the binding of hemin, a well-known physiological ligand of albumin. This measurement was performed using THz time-domain spectroscopy in dichroic transmission mode, achieving a sensitivity of approximately ~ 200 GHz/mM of the HSA:hemin complex. These preliminary results support the use of CMOS-compatible Ge-based THz plasmonic antennas as innovative sensors that could be monolithically integrated with conventional electronics for storage, processing, and communication into an all-in-one system.
(17) Sensing of Hemin Binding to Albumin using Ge-based Plasmonic Antennas Operating in the THz Range
E. Hardt, R. Varricchio, C.A. Chavarin, G. De Simone, O. Skibitzki, P. Ascenzi, A. di Masi, G. Capellini
IEEE Sensors Journal 25(8), 12881 (2025)
DOI: 10.1109/JSEN.2025.3545736, (iCampus II)
Albumin-based biofunctionalized biosensors have the potential to be utilized for the detection of physiological ligands (e.g., heme) and of pathogenic proteins. In human cells, heme is always bound to proteins due to its toxic nature. However, free heme can be present within tissue and in the bloodstream as a consequence of hemolysis or under pathological conditions like malaria or sickle cell anemia. Therefore, the development of an albumin-based heme biosensor could be relevant from a biomedical viewpoint. In this study, we developed a protein-sensing platform by immobilizing albumin on CMOS-compatible Ge-based THz plasmonic antennas via drop-cast biofunctionalization. To set up the biosensor, the sensing platform was used to quantitatively measure the binding of hemin, a well-known physiological ligand of albumin. This measurement was performed using THz time-domain spectroscopy in dichroic transmission mode, achieving a sensitivity of approximately ~ 200 GHz/mM of the HSA:hemin complex. These preliminary results support the use of CMOS-compatible Ge-based THz plasmonic antennas as innovative sensors that could be monolithically integrated with conventional electronics for storage, processing, and communication into an all-in-one system.
(18) Broadband Light Emission from GaAsP and GaInP Islands Grown on Silicon Nanotips Wafer via Nanoheteroepitaxy
N. Kafi, A. Rodrigues, I. Häusler, H. Ma, C. Netzel, A. Hammud, O. Skibitzki, M. Schmidbauer, F. Hatami
Applied Physics Letters 127(19), 191106 (2025)
DOI: 10.1063/5.0285546, (NHEQuanLEA)
We present the monolithic integration of GaAsxP1−x and GaxIn1−xP islands, selectively grown on a Si(001) nanotip wafer using gas-source molecular-beam epitaxy via a nanoheteroepitaxy approach. Optimal growth temperatures balancing selectivity and compositional control are 520–580 °C for GaAsP and 500–510 °C for GaInP. By adjusting the group III and V fluxes, island luminescence is tuned across a broad spectral range from 1.5 to 2.1 eV. High-resolution x-ray diffraction measurements on ensembles exceeding one million islands confirm that both GaAsP and GaInP islands are relaxed, while broad diffraction linewidths point to alloy fluctuations. Scanning transmission electron microscopy combined with energy-dispersive x-ray spectroscopy reveals compositional variations of up to 6% among the GaAsP islands, with nearly uniform composition within individual islands. In the case of GaInP, indium-rich regions are observed within single islands, with up to 11% variation across the ensemble. These compositional variations result in broadened or multiple luminescence peaks. Despite challenges in achieving full uniformity, this work demonstrates an alternative pathway for the monolithic integration of scalable III–V infrared-to-visible light emitters and detectors on silicon, advancing the development of microscale light sources for the silicon platform.
(19) Character Recognition Application of a Neural Circuit Including Lateral Inhibitory Mechanisms
D. Llobet Muñoz, I.K. Chatzipaschalis, A. Calomarde, A. Rubio
Proc. 40th Conference on Design of Circuits and Integrated Systems (DCIS 2025), 108 (2025)
DOI: 10.1109/DCIS67520.2025.11281935
(20) A Comprehensive Statistical Study of the Post-Programming Conductance Drift in HfO2-based Memristive Devices
D. Maldonado, C. Acal, H. Ortiz, A.M. Aguilera, J.E. Ruiz-Castro, A. Cantudo, A. Baroni, K.D.S. Reddy, S. Pechmann, M. Uhlmann, Ch. Wenger, E. Perez, J.B. Roldan
Materials Science in Semiconductor Processing 196, 109668 (2025)
DOI: 10.1016/j.mssp.2025.109668, (KI-IoT)
(21) Effects of the Compliance Current on the Switching of HfO2 and Al:HfO2 Memristive Devices: Characterization and Modeling
D. Maldonado, K.D.S. Reddy, S. Pechmann, Ch. Wenger, J.B. Roldán, E. Pérez
Proc. 15th Spanish Conference on Electron Devices (CDE 2025), (2025)
DOI: 10.1109/CDE66381.2025.11038898, (KI-IoT)
(22) A Statistical and Modeling Study on the Effects of Radiation on Au/Ta/ZrO2(Y)/Pt/Ti Memristive Devices
D. Maldonado, A. Cantudo, D.V. Guseinov, M.N. Koryazhkina, E.V. Okulich, D.I. Tetelbaum, N.O. Bartev, N.G. Danchenko, V.A. Pikar, A.V. Teterevkov, F. Jiménez-Molinos, A.N. Mikhaylov, J.B. Roldán
Chaos, Solitons & Fractals 191, 115909 (2025)
DOI: 10.1016/j.chaos.2024.115909
In this study we have investigated the impact of radiation on the performance and reliability of Au/Ta/ZrO2(Y)/Pt/Ti memristive devices, with a particular focus on understanding the changes induced by ion irradiation. A comprehensive experimental approach was employed, involving irradiation with various ion species, including H⁺, Ne⁺, O⁺, and Kr⁺ to simulate different radiation environments. Thus, advanced statistical and modeling techniques to analyze the effects of irradiation on the resistive switching (RS) characteristics of the devices have been employed. Results revealed significant alterations in the RS parameters post-irradiation, including set and reset voltages and currents. These changes were found to vary depending on the ion species and dosage, with heavier ions such as Kr⁺ causing more pronounced effects. The findings are supported by detailed Monte Carlo simulations, which provided insights into the distribution of vacancies within the memristive devices under neutron irradiation. The experimental data, combined with the modeling results, indicate that ion irradiation can lead to the formation of defect structures that critically affect the performance of memristive devices.
(23) Dependable Neuromorphic Computing-in-Memory Architectures
F. Merchant, A. Bende, M. Fritscher, S. Kvatinsky, S. Singh, V. Rana, R. Dittmann, K.D.S. Reddy, Ch. Wenger, F. Mir, M. Taouil, M. Dev Gomony, S. Hamdioui, H. Corporaal
Proc. 30th IEEE European Test Symposium (ETS 2025), (2025)
DOI: 10.1109/ETS63895.2025.11049617, (HYB-RISC)
(24) Hydrogen Sensing via Heterolytic H2 Activation at Room Temperature by Atomic Layer Deposited Ceria
C. Morales, R. Tschammer, E. Pozarowska, J. Kosto, I.J. Villar-Garcia, V. Pérez-Dieste, M. Favaro, D. Starr, P. Kapuscik, M. Mazur, D. Wojcieszak, J. Domaradzki, C.A. Chavarin, Ch. Wenger, K. Henkel, J.I. Flege
ChemSusChem 18(13), e202402342 (2025)
DOI: 10.1002/cssc.202402342, (iCampus II)
Ultrathin atomic layer deposited ceria films (< 20 nm) are capable of H2 heterolytic activation at room temperature, undergoing a significant reduction regardless of the absolute pressure, as measured under in-situ conditions by near ambient pressure X-ray photoelectron spectroscopy. ALD-ceria can gradually reduce as a function of H2 concentration under H2/O2 environments, especially for diluted mixtures below 10%. At room temperature, this reduction is limited to the surface region, where the hydroxylation of the ceria surface induces a charge transfer towards the ceria matrix, reducing Ce4+ cations to Ce3+. Thus, ALD-ceria replicates the expected sensing mechanism of metal oxides at low temperatures without using any noble metal decorating the oxide surface to enhance H2 dissociation. The intrinsic defects of the ALD deposit seem to play a crucial role since the post-annealing process capable of healing these defects leads to decreased film reactivity. The sensing behavior was successfully demonstrated in sensor test structures by resistance changes towards low concentrations of H2 at low operating temperatures without using noble metals. These promising results call for combining ALD-ceria with more conductive metal oxides, taking advantage of the charge transfer at the interface and thus modifying the depletion layer formed at the heterojunction.
(25) Bottom-Up Strategy to Develop Ultrathin Active Layers by Atomic Layer Deposition for Room Temperature Hydrogen Sensors
C. Morales, R. Tschammer, D. Guttmann, K. Henkel, J.I. Flege, C. Ruffert, C.A. Chavarin, Ch. Wenger,
Proc. 11. MikroSystemTechnik Kongress (MST 2025), 71 (2025)
(iCampus II)
(26) In Situ X-Ray Photoelectron Spectroscopy Study of Atomic Layer Deposited Cerium Oxide on SiO2: Substrate Influence on the Reaction Mechanism During the Early Stages of Growth
C. Morales, M. Gertig, M. Kot, C.A. Chavarin, M.A. Schubert, M.H. Zoellner, Ch. Wenger, K. Henkel, J.I. Flege
Advanced Materials Interfaces 12(5), 2400537 (2024)
DOI: 10.1002/admi.202400537, (iCampus II)
Thermal atomic layer deposition (ALD) of cerium oxide using commercial Ce(thd)4 precursor and O3 on SiO2 substrates is studied employing in-situ X-ray photoelectron spectroscopy (XPS). The system presents a complex growth behavior determined by the change in the reaction mechanism when the precursor interacts with the substrate or the cerium oxide surface. During the first growth stage, non-ALD side reactions promoted by the substrate affect the growth per cycle, the amount of carbon residue on the surface, and the oxidation degree of cerium oxide. On the contrary, the second growth stage is characterized by a constant growth per cycle in good agreement with the literature, low carbon residues, and almost fully oxidized cerium oxide films. This distinction between two growth regimes is not unique to the CeOx/SiO2 system but can be generalized to other metal oxide substrates. Furthermore, the film growth deviates from the ideal layer-by-layer mode, forming micrometric inhomogeneous and defective flakes that eventually coalesce for deposit thicknesses above 10 nm. The ALD-cerium oxide films present less order and a higher density of defects than films grown by physical vapor deposition techniques, likely affecting their reactivity in oxidizing and reducing conditions.
(27) Effects of Temperature and Light on CeO2/SnO2 Thin-Film Hydrogen Sensors
A. Mudundi, A. Kalra, R. Tschammer, C. Morales, J.I. Flege, I.A. Fischer, C.A. Chavarin, Ch. Wenger
Proc. 11. MikroSystemTechnik Kongress (MST 2025), 20 (2025)
(iCampus II)
(28) Cryogenic Characterization of HfO₂-Based RRAM: Exploring Multilevel Switching from 300 K to 1.5 K for Neuromorphic Quantum Computing
E. Perez-Bosch Quesada, A. Mistroni, R. Jia, K.D.S. Reddy, M. Fritscher, F. Reichmann, H. Castan, S. Dueñas, Ch. Wenger, E. Perez
Proc. 57th International Conference on Solid State Devices and Materials (SSDM 2025), 703 (2025)
(INSEKT)
(29) Impact of the Series Resistance on Switching Characteristics of 1T1R HfO2-based RRAM Devices
E. Perez, D. Maldonado, S. Pechmann, K.D.S. Reddy, M. Uhlmann, A. Hagelauer, J.B. Roldan, Ch. Wenger
Proc. 15th Spanish Conference on Electron Devices (CDE 2025), (2025)
DOI: 10.1109/CDE66381.2025.11038868, (KI-IoT)
(30) Analytical Model for Parasitic Resistances of Crossbar Arrays Suitable for Open-Loop Programming Schemes Reliability Analysis
T. Rizzi, T. Zanotti, N. Lepri, E. Pérez, F.M. Puglisi, D. Ielmini, C. Zambelli
Proc. IEEE International Integrated Reliability Workshop (IIRW 2024), (2025)
DOI: 10.1109/IIRW62856.2024.10947147, (HYB-RISC)
(31) Monolithically Integrated GaAs Nanoislands on CMOS-Compatible Si Nanotips using GS-MBE
A. Rodrigues, A. Kamath, H. Illner, N. Kafi, O. Skibitzki, M. Schmidbauer, F. Hatami
Nanomaterials (MDPI) 15(14), 1083 (2025)
DOI: 10.3390/nano15141083, (NHEQuanLEA)
The monolithic integration of III-V semiconductors with silicon (Si) is a critical step toward advancing optoelectronic and photonic devices. In this work, we present GaAs nanoheteroepitaxy (NHE) on Si nanotips using gas-source molecular beam epitaxy (GS-MBE). We discuss the selective growth of fully relaxed GaAs nanoislands on complementary metal oxide semiconductor (CMOS)-compatible Si(001) nanotip wafers. Nanotip wafers were fabricated using a state-of-the-art 0.13 μm SiGe Bipolar CMOS pilot line on 200 mm wafers. Our investigation focuses on understanding the influence of the growth conditions on the morphology, crystalline structure, and defect formation of the GaAs islands. The morphological, structural, and optical properties of the GaAs islands were characterized using scanning electron microscopy, high-resolution X-ray diffraction, and photoluminescence spectroscopy. For samples with less deposition, the GaAs islands exhibit a monomodal size distribution, with an average effective diameter ranging between 100 and 280 nm. These islands display four distinct facet orientations corresponding to the {001} planes. As the deposition increases, larger islands with multiple crystallographic facets emerge, accompanied by a transition from a monomodal to a bimodal growth mode. Single twinning is observed in all samples. However, with increasing deposition, not only a bimodal size distribution occurs, but also the volume fraction of the twinned material increases significantly. These findings shed light on the growth dynamics of nanoheteroepitaxial GaAs and contribute to ongoing efforts toward CMOS-compatible Si-based nanophotonic technologies.
(32) Investigation of Dislocations Introduced in Si Wafer During Flash Lamp Annealing by Photoluminescence Spectroscopy
D. Ryzhak, G. Kissinger, A. Ehlert, A. Sattler, D. Spirito, D. Kot
Physica Status Solidi A 222(8), 2400753 (2025)
DOI: 10.1002/pssa.202400753, (Siltronic Project)
Dislocations are generated in Si wafers during flash lamp annealing for 20 ms. The samples have been etched to different depths and macro-photoluminescence (PL) spectra have been recorded for different dislocation densities. A micro-PL investigation is also carried out on a cross section of a sample. Four characteristic emission peaks are found, which are the well-known D1, D2, D3, and D4 lines. The findings demonstrate a significant influence of the defect densities on the PL spectra of the D lines by using both the micro- and the macro-PL setups, and show a correlation of the PL intensities with etch pit density measured against the depth of the wafer. Additionally, the D lines dependency on temperature is explored, offering insights into the underlying mechanisms. The D lines exhibit a pronounced temperature dependence, which can be attributed to various factors including phonon interactions and thermal expansion effects. The influence of nickel contamination is also examined.
(33) Photoluminescence Enhancement in Germanium All-Dielectric Metasurfaces
J. Schlipf, D. Ryzhak, P. Oleynik, G. Capellini, Y. Yamamoto, O. Skibitzki, I.A. Fischer
Proc. 10th International Symposium on Control of Semiconductor Interfaces (ISCSI-X), the International Conference on Silicon Epitaxy and International SiGe Technology and Device Meeting (ICSI/ISTDM 2025), 177 (2025)
(OASYS)
(34) Photoluminescence Enhancement in Germanium All-Dielectric Metasurfaces
J. Schlipf, D. Ryzhak, P. Oleynik, G. Capellini, Y. Yamamoto, O. Skibitzki, I.A. Fischer
Proc. 10th International Symposium on Control of Semiconductor Interfaces (ISCSI-X), the International Conference on Silicon Epitaxy and International SiGe Technology and Device Meeting (ICSI/ISTDM 2025), 177 (2025)
(iCampus II)
(35) AI-Driven Model for Optimized Pulse Programming of Memristive Devices
B. Spetzler, M. Fritscher, S. Park, N. Kim, Ch. Wenger, M. Ziegler
APL Machine Learning 3(2), 026103 (2025)
DOI: 10.1063/5.0251113, (DI-SIGN-HEP)
Next-generation artificial intelligence (AI) hardware based on memristive devices offers a promising approach to reducing the increasingly large energy consumption of AI applications. However, programming memristive AI hardware to achieve a desired synaptic weight configuration remains challenging because it requires accurate and energy-efficient algorithms for selecting the optimal weight-update pulses. Here, we present a computationally efficient AI model for predicting the weight update of memristive devices and guiding device programming. The synaptic weight-update behavior of bilayer HfO2/TiO2 memristive devices is characterized over a range of pulse parameters to provide experimental data for the AI model. Three different artificial neural network (ANN) configurations are trained and evaluated regarding the amount of training data required for accurate predictions and the computational costs. Finally, we apply the model to an antipulse weight-update process to demonstrate its performance. The results show that accurate and computationally inexpensive predictions are possible with comparatively few datasets and small ANNs. The normalized weight-update processes are predicted with accuracies comparable with larger model architectures but require only 896 floating point operations and 8.33 nJ per inference. This makes the model a promising candidate for integration into AI-driven device controllers as a precise and energy-efficient solution for memristive device programming.
(36) AI-Driven Model for Optimized Pulse Programming of Memristive Devices
B. Spetzler, M. Fritscher, S. Park, N. Kim, Ch. Wenger, M. Ziegler
APL Machine Learning 3(2), 026103 (2025)
DOI: 10.1063/5.0251113, (HYB-RISC)
Next-generation artificial intelligence (AI) hardware based on memristive devices offers a promising approach to reducing the increasingly large energy consumption of AI applications. However, programming memristive AI hardware to achieve a desired synaptic weight configuration remains challenging because it requires accurate and energy-efficient algorithms for selecting the optimal weight-update pulses. Here, we present a computationally efficient AI model for predicting the weight update of memristive devices and guiding device programming. The synaptic weight-update behavior of bilayer HfO2/TiO2 memristive devices is characterized over a range of pulse parameters to provide experimental data for the AI model. Three different artificial neural network (ANN) configurations are trained and evaluated regarding the amount of training data required for accurate predictions and the computational costs. Finally, we apply the model to an antipulse weight-update process to demonstrate its performance. The results show that accurate and computationally inexpensive predictions are possible with comparatively few datasets and small ANNs. The normalized weight-update processes are predicted with accuracies comparable with larger model architectures but require only 896 floating point operations and 8.33 nJ per inference. This makes the model a promising candidate for integration into AI-driven device controllers as a precise and energy-efficient solution for memristive device programming.
(37) AI-Driven Model for Optimized Pulse Programming of Memristive Devices
B. Spetzler, M. Fritscher, S. Park, N. Kim, Ch. Wenger, M. Ziegler
APL Machine Learning 3(2), 026103 (2025)
DOI: 10.1063/5.0251113, (6G-RIC)
Next-generation artificial intelligence (AI) hardware based on memristive devices offers a promising approach to reducing the increasingly large energy consumption of AI applications. However, programming memristive AI hardware to achieve a desired synaptic weight configuration remains challenging because it requires accurate and energy-efficient algorithms for selecting the optimal weight-update pulses. Here, we present a computationally efficient AI model for predicting the weight update of memristive devices and guiding device programming. The synaptic weight-update behavior of bilayer HfO2/TiO2 memristive devices is characterized over a range of pulse parameters to provide experimental data for the AI model. Three different artificial neural network (ANN) configurations are trained and evaluated regarding the amount of training data required for accurate predictions and the computational costs. Finally, we apply the model to an antipulse weight-update process to demonstrate its performance. The results show that accurate and computationally inexpensive predictions are possible with comparatively few datasets and small ANNs. The normalized weight-update processes are predicted with accuracies comparable with larger model architectures but require only 896 floating point operations and 8.33 nJ per inference. This makes the model a promising candidate for integration into AI-driven device controllers as a precise and energy-efficient solution for memristive device programming.
