TY - JOUR AU - Darwish, Mahmoud Ibrahim Azmi AU - Zhabura, Yana AU - Pohl, László TI - Recent Advances of VO2 in Sensors and Actuators JF - NANOMATERIALS J2 - NANOMATERIALS-BASEL VL - 14 PY - 2024 IS - 7 PG - 22 SN - 2079-4991 DO - 10.3390/nano14070582 UR - https://m2.mtmt.hu/api/publication/34761133 ID - 34761133 N1 - Department of Electron Devices, Faculty of Electrical Engineering and Informatics, Budapest University of Technology and Economics, Budapest, 1111, Hungary Department of Electrical Engineering and Automation, School of Electrical Engineering, Aalto University, Espoo, 02150, Finland Export Date: 22 April 2024 Correspondence Address: Darwish, M.; Department of Electron Devices, Hungary; email: darwishm@edu.bme.hu Correspondence Address: Pohl, L.; Department of Electron Devices, Hungary; email: pohl.laszlo@vik.bme.hu AB - Vanadium dioxide (VO2) stands out for its versatility in numerous applications, thanks to its unique reversible insulator-to-metal phase transition. This transition can be initiated by various stimuli, leading to significant alterations in the material’s characteristics, including its resistivity and optical properties. As the interest in the material is growing year by year, the purpose of this review is to explore the trends and current state of progress on some of the applications proposed for VO2 in the field of sensors and actuators using literature review methods. Some key applications identified are resistive sensors such as strain, temperature, light, gas concentration, and thermal fluid flow sensors for microfluidics and mechanical microactuators. Several critical challenges have been recognized in the field, including the expanded investigation of VO2-based applications across multiple domains, exploring various methods to enhance device performance such as modifying the phase transition temperature, advancing the fabrication techniques for VO2 structures, and developing innovative modelling approaches. Current research in the field shows a variety of different sensors, actuators, and material combinations, leading to different sensor and actuator performance input ranges and output sensitivities. LA - English DB - MTMT ER - TY - JOUR AU - Darwish, Mahmoud Ibrahim Azmi AU - Pohl, László TI - Insulator Metal Transition-Based Selector in Crossbar Memory Arrays JF - ELECTRONIC MATERIALS J2 - ELECTRON MATER VL - 5 PY - 2024 IS - 1 SP - 17 EP - 29 PG - 13 SN - 2673-3978 DO - 10.3390/electronicmat5010002 UR - https://m2.mtmt.hu/api/publication/34681240 ID - 34681240 N1 - Export Date: 5 April 2024 Correspondence Address: Pohl, L.; Department of Electron Devices, Hungary; email: pohl.laszlo@vik.bme.hu AB - This article investigates resistive random access memory (ReRAM) crossbar memory arrays, which is a notable development in non-volatile memory technology. We highlight ReRAM’s competitive edge over NAND, NOR Flash, and phase-change memory (PCM), particularly in terms of endurance, speed, and energy efficiency. This paper focuses on the architecture of crossbar arrays, where memristive devices are positioned at intersecting metal wires. We emphasize the unique resistive switching mechanisms of memristors and the challenges of sneak path currents and delve into the roles and configurations of selectors, particularly focusing on the one-selector one-resistor (1S1R) architecture with an insulator–metal transition (IMT) based selector. We use SPICE simulations based on defined models to examine a 3 × 3 1S1R ReRAM array with vanadium dioxide selectors and titanium dioxide film memristors, assessing the impact of ambient temperature and critical IMT temperatures on array performance. We highlight the operational regions of low resistive state (LRS) and high resistive state (HRS), providing insights into the electrical behavior of these components under various conditions. Lastly, we demonstrate the impact of selector presence on sneak path currents. This research contributes to the overall understanding of ReRAM crossbar arrays integrated with IMT material-based selectors. LA - English DB - MTMT ER - TY - CHAP AU - Pohl, László ED - Poppe, András TI - HexMG: A Circuit-Model Based Finite Multi-Domain Simulator T2 - 2023 29th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC) PB - IEEE CY - Budapest SN - 9798350318623 PY - 2023 PG - 7 DO - 10.1109/THERMINIC60375.2023.10325907 UR - https://m2.mtmt.hu/api/publication/34448278 ID - 34448278 N1 - Conference code: 194796 Export Date: 22 December 2023 Correspondence Address: Pohl, L.; Budapest University of Technology and Economics Megyetem, Hungary; email: pohl.laszlo@vik.bme.hu AB - This paper presents a new open-source simulator that aims to provide a tool to study a wide range of current and future problems requiring high-resolution distributed simula tion in engineering practice, especially in microelectronics. The problem to be studied is defined as a circuit model, which can be specified by a SPICE-like description. The simulator solves this circuit using the highly efficient Successive Network Reduction Method, optimized specifically for solving circuit models of fields discretized by the Finite Differences or Finite Volumes methods. The circuits can be extended with programmable special components: controllers, to easily implement special tasks such as hysteresis or ray tracing modelling. © 2023 IEEE. LA - English DB - MTMT ER - TY - CHAP AU - Darwish, Mahmoud Ibrahim Azmi AU - Pohl, László ED - Poppe, András TI - SPICE Modeling of Insulator-Metal Transition Devices with Hysteresis T2 - 2023 29th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC) PB - IEEE CY - Budapest SN - 9798350318623 PY - 2023 PG - 5 DO - 10.1109/THERMINIC60375.2023.10325868 UR - https://m2.mtmt.hu/api/publication/34448274 ID - 34448274 N1 - Conference code: 194796 Export Date: 22 December 2023 Correspondence Address: Darwish, M.; Budapest University of Technology and Economics, Hungary; email: darwishm@edu.bme.hu AB - A New SPICE model for insulator-metal transition (IMT) devices is presented in this paper. The combined influences of the electric field and Joule heating are considered, allowing a transition from the high-resistance monoclinic phase to the low-resistance metallic one. Hysteresis, observed in specific IMT materials such as vanadium dioxide, is effectively addressed. The model's accuracy was validated using experimental results and electro-thermal FVM simulations. It has been implemented in VHDL-AMS, ensuring its compatibility with SPICE simulators like Xpedition AMS and PartQuest Explore, which were employed in this research. The model characterizes three specific device states, heating, cooling, and equilibrium. Transition dynamics between these states are tied to historical temperature data, represented as the device's temperature time derivative. To our knowledge, this model is the first IMT compact model that addresses hysteresis and is the first VHDL-AMS for IMT devices. With this development, circuit designers are provided with tools to fully explore the potential of VO2 and similar IMT devices to design and realize next-generation electrical circuits. © 2023 IEEE. LA - English DB - MTMT ER - TY - CHAP AU - Darwish, Mahmoud Ibrahim Azmi AU - Al-abassi, Salam AU - Neumann, Péter Lajos AU - Mizsei, János AU - Pohl, László ED - Vadim, Tsoi ED - Lorenzo, Codecasa ED - Bernhard, Wunderle TI - Application of Vanadium Dioxide for Thermal Sensing T2 - Proceedings of the 27th International Workshop on THERMal INvestigations of ICs and Systems (THERMINIC'21 online) PB - IEEE CY - Piscataway (NJ) SN - 9781665418973 PY - 2021 SP - 249 EP - 252 PG - 4 DO - 10.1109/THERMINIC52472.2021.9626518 UR - https://m2.mtmt.hu/api/publication/32236564 ID - 32236564 N1 - Funding Agency and Grant Number: Stipendium Hungaricum Scholarship Program of the Hungarian Government Funding text: The research reported in this paper and carried out at Budapest University of Technology and Economics was supported by the Stipendium Hungaricum Scholarship Program of the Hungarian Government. AB - Thermal sensors are widely used in different areas such as, automotive, defense, healthcare, and fire protection. Heat management is a hot topic nowadays, especially in electronics and power electronic packages, due to the miniaturization of semiconductor devices dimensions. New materials and concepts are studied to develop thermal sensors with more excellent reliability and sensitivity. Vanadium dioxide is a strongly correlated electron material with interesting thermal and optical properties due to its transition from a low-conducting phase to a high-conducting phase called metal-to-insulator transition. This study investigates two different models to use vanadium dioxide as a sensing element by presenting simulations performed on SUNRED simulator. LA - English DB - MTMT ER - TY - CHAP AU - Al-abassi, Salam AU - Darwish, Mahmoud Ibrahim Azmi AU - Pohl, László AU - Mizsei, János AU - Neumann, Péter Lajos ED - Vadim, Tsoi ED - Lorenzo, Codecasa ED - Bernhard, Wunderle TI - Comparative multiphysics simulation of VO2 based lateral devices T2 - Proceedings of the 27th International Workshop on THERMal INvestigations of ICs and Systems (THERMINIC'21 online) PB - IEEE CY - Piscataway (NJ) SN - 9781665418973 PY - 2021 SP - 178 EP - 181 PG - 4 DO - 10.1109/THERMINIC52472.2021.9626517 UR - https://m2.mtmt.hu/api/publication/32236558 ID - 32236558 AB - Due to reaching the end of Moore’s era and minimising CMOS technology becomes difficult. Finding different materials to keep electronic devices evolving is a matter of scientists. A thermal electronic logic circuit (TELC) is one of the most prominent alternatives that has been proposed recently. Vanadium dioxide (VO2) is an essential material that has been utilised in TELC due to its thermal and electrical properties. VO2 transits its electrical property from the semiconductor phase into the metal phase at around 67oC. In this paper, two numerical methods were used to determine the electrical and thermal characteristics of VO2, and measured data compared the results. The phase-change material behaviour was modelled by two different softwares using different simulation methods, finite volume method FVM and finite element method FEM. The sample preparation and the thermal and electrical measurements were carried out in our cleanroom. LA - English DB - MTMT ER - TY - CHAP AU - Darwish, Mahmoud Ibrahim Azmi AU - Neumann, Péter Lajos AU - Mizsei, János AU - Pohl, László ED - IEEE, , TI - Study of Dynamic Simulation for Thermal-Electronic Logic Circuits T2 - Proceedings of the 26th International Workshop on THERMal INvestigations of ICs and Systems (THERMINIC) PB - IEEE CY - Piscataway (NJ) SN - 9781728176437 PY - 2020 SP - 97 EP - 102 PG - 6 DO - 10.1109/THERMINIC49743.2020.9420495 UR - https://m2.mtmt.hu/api/publication/31778148 ID - 31778148 N1 - Export Date: 9 June 2022 Correspondence Address: Darwish, M.; Budapest University of Technology and Economics (BME)Hungary; email: mahmoud@eet.bme.hu AB - Emerging devices and materials in computing industry are recently of great interest because classical silicon-based circuit development is saturating due to scaling limits. Thermal-electronic logic circuit (TELC) concept is a promising approach to enhance conventional CMOS circuits or even replace them. Semiconductor-to-metal transition (SMT) of vanadium dioxide (VO2) is the main part of TELC as it allows transmission and control of information flow both electrically and thermally. The first TELC inverter is introduced in this article, dynamic simulations are performed to test its behavior and relation between propagation delay and input voltage is demonstrated. A new phase transition model is used to upgrade our SUNRED simulator. This new version is accurate and proved to be suitable for dynamic simulations. This article presents first dynamic simulation of SMT material. LA - English DB - MTMT ER - TY - JOUR AU - Pohl, László AU - Hantos, Gusztáv AU - Hegedüs, János AU - Németh, Márton AU - Kohári, Zsolt AU - Poppe, András TI - Mixed Detailed and Compact Multi-Domain Modeling to Describe CoB LEDs JF - ENERGIES J2 - ENERGIES VL - 13 PY - 2020 IS - 16 PG - 38 SN - 1996-1073 DO - 10.3390/en13164051 UR - https://m2.mtmt.hu/api/publication/31395925 ID - 31395925 AB - Large area multi-chip LED devices, such as chip-on-board (CoB) LEDs, require the combined use of chip-level multi-domain compact LED models (Spice-like compact models) and the proper description of distributed nature of the thermal environment (the CoB substrate and phosphor) of the LED chips. In this paper, we describe such a new numerical solver that was specifically developed for this purpose. For chip-level, the multi-domain compact modeling approach of the Delphi4LED project is used. This chip-level model is coupled to a finite difference scheme based numerical solver that is used to simulate the thermal phenomena in the substrate and in the phosphor (heat transfer and heat generation). Besides solving the 3D heat-conduction problem, this new numerical simulator also tracks the propagation and absorption of the blue light emitted by the LED chips, as well as the propagation and absorption of the longer wavelength light that is converted by the phosphor from blue. Heat generation in the phosphor, due to conversion loss (Stokes shift), is also modeled. To validate our proposed multi-domain model of the phosphor, dedicated phosphor and LED package samples with known resin—phosphor powder ratios and known geometry were created. These samples were partly used to identify the nature of the temperature dependence of phosphor-conversion efficiency and were also used as simple test cases to “calibrate” and test the new numerical solver. With the models developed, combined simulation of the LED chip and the CoB substrate + phosphor for a known CoB LED device is shown, and the simulation results are compared to measurement results. LA - English DB - MTMT ER - TY - JOUR AU - Darwish, Mahmoud Ibrahim Azmi AU - Neumann, Péter Lajos AU - Mizsei, János AU - Pohl, László TI - Electro-Thermal Simulation of Vertical VO2 Thermal-Electronic Circuit Elements JF - ENERGIES J2 - ENERGIES VL - 13 PY - 2020 IS - 13 SN - 1996-1073 DO - 10.3390/en13133447 UR - https://m2.mtmt.hu/api/publication/31369246 ID - 31369246 N1 - Cited By :2 Export Date: 21 September 2022 Correspondence Address: Pohl, L.; Department of Electron Devices, Hungary; email: pohl@eet.bme.hu AB - Advancement of classical silicon-based circuit technology is approaching maturity and saturation. The worldwide research is now focusing wide range of potential technologies for the “More than Moore” era. One of these technologies is thermal-electronic logic circuits based on the semiconductor-to-metal phase transition of vanadium dioxide, a possible future logic circuits to replace the conventional circuits. In thermal-electronic circuits, information flows in a combination of thermal and electronic signals. Design of these circuits will be possible once appropriate device models become available. Characteristics of vanadium dioxide are under research by preparing structures in laboratory and their validation by simulation models. Modeling and simulation of these devices is challenging due to several nonlinearities, discussed in this article. Introduction of custom finite volumes method simulator has however improved handling of special properties of vanadium dioxide. This paper presents modeling and electro-thermal simulation of vertically structured devices of different dimensions, 10 nm to 300 nm layer thicknesses and 200 nm to 30 um radii. Results of this research will facilitate determination of sample sizes in the next phase of device modeling. LA - English DB - MTMT ER - TY - JOUR AU - Bognár, György AU - Takács, Gábor AU - Szabó, Péter Gábor AU - Rózsás, Gábor AU - Pohl, László AU - Plesz, Balázs TI - Integrated Thermal Management in System-on-Package Devices JF - PERIODICA POLYTECHNICA-ELECTRICAL ENGINEERING AND COMPUTER SCIENCE J2 - PERIOD POLYTECH ELECTR ENG COMP SCI VL - 64 PY - 2020 IS - 2 SP - 200 EP - 210 PG - 11 SN - 2064-5260 DO - 10.3311/PPee.14986 UR - https://m2.mtmt.hu/api/publication/31028059 ID - 31028059 N1 - Export Date: 28 September 2022 Correspondence Address: Bognár, G.; Department of Electron Devices, P.O.B. 91, Hungary; email: bognar@eet.bme.h AB - Thanks to the System-on-Package technology (SoP) the integration of different elements into a single package was enabled. However, from the thermal point of view the heat removal path in modern packaging technologies (FCBGA) goes through several layers of thermal interface material (TIM) that together with the package material create a relatively high thermal resistance which may lead to elevated chip temperature which causes functional error or other malfunctions. In our concept, we overcome this problem by creating integrated microfluidic channel based heat sink structures that can be used for cooling the high heat dissipation semiconductor devices (e.g.: processors, high power transistor or concentrated solar cells). These microchannel cooling assemblies can be integrated into the backside of the substrate of the semiconductor devices or into the system assemblies in SoP technology. In addition to the realization of the novel CMOS compatible microscale cooling device we have developed precise and valid measurement methodology, simulation cases studies and a unique compact model that can be added to numerical simulators as an external node. In this paper the achievements of a larger research are summarized as it required the cooperation of several experts in their fields to fulfil the goal of creating a state-of-the-art demonstrator. LA - English DB - MTMT ER -