Article
Computer Science, Information Systems
Yuchen Li, Sen Huang, Xinhua Wang, Qimeng Jiang, Xinyu Liu
Summary: In this study, the temperature-dependent ON-state breakdown BVON of AlGaN/GaN HEMTs with an AlGaN back barrier was investigated using the gate current extraction technique. It was found that the impact ionization of acceptor-like traps is responsible for the ON-state breakdown in HEMTs when the 2DEG channel is marginally turned on. Additionally, the characteristic electric field of impact ionization was extracted and shown to have a U-shaped temperature dependence.
Article
Physics, Applied
Xin Chen, Yaozong Zhong, Shumeng Yan, Xiaolu Guo, Hongwei Gao, Xiujian Sun, Haodong Wang, Fangqing Li, Yu Zhou, Meixin Feng, Ercan Yilmaz, Qian Sun, Hui Yang
Summary: The characteristics of an AlGaN/GaN high-electron-mobility transistor buffer structure are studied and optimized by employing an AlN/GaN superlattice (SL) structure. The influence of buffer traps on carrier transport behaviors and electrical performance for SL buffer structures under a high electric field is analyzed. The AlN/GaN SL buffer structures are further optimized with various AlN/GaN thickness ratios and their total thickness, achieving a high breakdown voltage and suppressing the buffer trapping effect.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
J. Mimila-Arroyo, A. S. Arreola-Pina, F. Jomard, A. Lusson
Summary: This study investigates the effect of hydrogenation experimental parameters (plasma power, sample temperature, and duration) on the dose and distribution of hydrogen throughout the structure. The results reveal that the dose is proportional to the square of the plasma power, increases linearly with hydrogenation time, and is slightly related to the sample temperature. These findings provide insights on how to improve the performance of AlGaN/GaN HEMTs.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2023)
Article
Physics, Applied
Akiyoshi Inoue, Sakura Tanaka, Takashi Egawa, Makoto Miyoshi
Summary: In this study, HFETs based on an Al0.36Ga0.64N-channel heterostructure with a dual AlN/AlGaInN barrier layer were successfully fabricated and characterized. The devices showed improved performance in terms of current density and breakdown voltage. Additionally, the devices adopting the dual AlN/AlGaInN barrier layer exhibited significantly smaller gate leakage currents.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Automation & Control Systems
Moinul Shahidul Haque, Seungdeog Choi
Summary: This article proposes a novel sparse kernel ridge regression assisted particle filter method for estimating the remaining useful life of gallium nitride field-effect transistors in emerging power electronics systems. The method aims to overcome challenges such as large variation in RUL estimation under noise uncertainty and sample degeneracy. By introducing SKRR in resampling the probability density function estimation, the method significantly enhances estimation accuracy and can effectively trace sudden changes in fault precursor trajectories.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Austin Lee Hickman, Reet Chaudhuri, Samuel James Bader, Kazuki Nomoto, Lei Li, James C. M. Hwang, Huili Grace Xing, Debdeep Jena
Summary: The shift to the aluminum nitride platform offers smarter, highly-scaled heterostructure design to improve the performance of III-nitride amplifiers, enabling maximum high-power, high-speed potential for mm-wave communication and high-power logic applications.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2021)
Article
Physics, Applied
Wataru Miyazaki, Hajime Tanaka, Nobuya Mori
Summary: The effects of strain on the band structure of GaN were investigated using an empirical tight-binding method. The impacts on its bandgap, carrier effective mass, and group velocity were discussed. The cause of the variation of the band structure, including effective-mass exchange, was discussed by analyzing the orbital components at the top of the valence band. Analysis of the average group velocity showed that tensile uniaxial or compressive biaxial strain may be beneficial for achieving higher breakdown voltage in vertical GaN devices due to the smaller group velocity of the valence band. Similarly, higher breakdown voltages were predicted for horizontal devices due to tensile biaxial strain.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
Rui Shan Low, Joel T. Asubar, Ali Baratov, Shunsuke Kamiya, Itsuki Nagase, Shun Urano, Shinsaku Kawabata, Hirokuni Tokuda, Masaaki Kuzuhara, Yusui Nakamura, Kenta Naito, Tomohiro Motoyama, Zenji Yatabe
Summary: This study fabricates AlGaN/GaN metal-insulator-semiconductor (MIS) capacitors and high-electron-mobility transistors (MIS-HEMTs) using a 5 nm thick Al2O3 dielectric deposited by mist chemical vapor deposition (mist-CVD) technique. The results show that the mist-Al2O3/AlGaN interface has high quality, and the mist MIS-HEMTs exhibit improved performance compared to traditional HEMTs, indicating the potential of mist-CVD Al2O3 in high-performance GaN-based MIS-HEMT development.
APPLIED PHYSICS EXPRESS
(2021)
Article
Computer Science, Information Systems
Gianni Bosi, Antonio Raffo, Valeria Vadala, Rocco Giofre, Giovanni Crupi, Giorgio Vannini
Summary: In this paper, we investigate the degradation effects observed on 0.15-μm GaN HEMT devices operating under realistic power amplifier conditions through experimental methods. A low-frequency load-pull characterization technique is utilized to apply power amplifier conditions to the devices under test (DUT), providing information consistent with RF operation. The experiments are conducted at different temperatures and compare the degradation effects under different power amplifier operations.
Article
Engineering, Electrical & Electronic
Junya Yaita, Koichi Fukuda, Atsushi Yamada, Takuya Iwasaki, Shu Nakaharai, Junji Kotani
Summary: The study identified the primary reason for the reduced electron mobility in QW GaN-HEMT and proposed a solution to alleviate the electric field and increase electron mobility. As a result, the electron mobility of the QW GaN-HEMT structure was significantly improved.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Yijun Shi, Yiqiang Chen, Yun Huang, Zhiyuan He, Wanjun Chen, Ruize Sun, Bin Yao, Hongyue Wang, Qingzhong Xiao, Guoguang Lu, Bo Zhang
Summary: In this study, a novel GaN electrostatic discharge (ESD) protection clamp is proposed to enhance the ESD reliability of the conventional p-GaN HEMT. The proposed clamp features a low triggering voltage and can withstand a high second breakdown current, effectively discharging and protecting the transient electrostatic charges on the gate structure.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Yasuyuki Miyamoto, Kozo Makiyama
Summary: The high breakdown voltage achieved by loading a high-k film in the gate-drain region was recently studied. However, the uniform high-k film has limitations in modulating the electric field distribution, resulting in a stronger electric field near the gate side compared to the drain side. This study proposes the modulation of high-k film thickness in the lateral direction to control the electric field distribution in the channel of a gallium nitride (GaN) high electron mobility transistor (HEMT). Compared to a uniform film, this modulation weakens the electric field near the gate and creates a negative gradient. Simulation results show a 20% increase in the voltage at which impact ionization occurs, attributed to reduced gate leakage current and improved electric field distribution. The maximum electric field also increases in the proposed structure when the electric field slope is negative.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Chemistry, Multidisciplinary
Jinyuan Xu, Ailing Chen, Linfeng Yu, Donghai Wei, Qikun Tian, Huimin Wang, Zhenzhen Qin, Guangzhao Qin
Summary: In this paper, the stable structure of a monolayer CuI with ultra-low thermal conductivity and an ultra-wide direct bandgap is predicted from first-principles calculations. This material shows potential applications in transparent and wearable electronics.
Article
Engineering, Electrical & Electronic
David Maria Tobaldi, Valentina Trimini, Arianna Creti, Mauro Lomascolo, Stefano Dicorato, Maria Losurdo, Adriana Passaseo, Vittorianna Tasco
Summary: The study successfully developed a remote plasma MOCVD method for epitaxial growth of high-quality GaN/AlGaN heterostructures. This method has lower growth temperature and uses remote plasma instead of ammonia, providing a cost-effective and green approach for high-quality heteroepitaxy.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Engineering, Electrical & Electronic
Prakash Pandey, Tolen M. Nelson, William M. Collings, Michael R. Hontz, Daniel G. Georgiev, Andrew D. Koehler, Travis J. Anderson, James C. Gallagher, Geoffrey M. Foster, Alan Jacobs, Mona A. Ebrish, Brendan P. Gunning, Robert J. Kaplar, Karl D. Hobart, Raghav Khanna
Summary: A simple edge termination structure for a GaN p-n diode is proposed, which has been empirically validated to increase breakdown capability. This technique reduces complexity in manufacturing and improves the device's voltage-blocking ability.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Physics, Multidisciplinary
Ching-Chen Yeh, Siang-Chi Wang, Shun-Tsung Lo, Gil-Ho Kim, D. A. Ritchie, Gottfried Strasser, Chi-Te Liang
Summary: We have observed a temperature-independent point Bc in the longitudinal resistance Rxx of a GaAs-based two-dimensional electron gas during the quantum Hall plateau-plateau transition. This discovery allows us to re-examine the spin-degenerate plateau-plateau transition and calculate the critical exponent kappa by measuring the movement of the Rxx peak with respect to Bc at different temperatures. We propose measuring the maximum derivative of Hall resistivity d(rho xy)/dB similar to T-kappa as well as the movement of Rxx at different temperatures to determine kappa s using two independent methods. When the peak movement deviates significantly from Bc, a kappa value of 0.54 +/- 0.04 can be measured, which is considerably different from the value (0.21 +/- 0.02) in some spin-degenerate systems.
CHINESE JOURNAL OF PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
E. Brusaterra, E. Bahat Treidel, F. Brunner, M. Wolf, A. Thies, J. Wurfl, O. Hilt
Summary: By optimizing the doping concentration of gallium nitride drift layers with a given thickness of 5 μm, we were able to improve the high voltage and low resistance performance of vertical electronic devices. Our optimization procedure used an empirical mobility model to maximize the power figure-of-merit of the devices. We grew quasi-vertical gallium nitride-based pn-diodes on sapphire substrates and compared the results to theoretical breakdown voltage values, finding a pn-diode with 545 V avalanche breakdown voltage and a power figure-of-merit of 874 MW/cm(2), as well as a punch-through pn-diode with 920 V breakdown voltage and a power figure-of-merit of 1.48 GW/cm(2).
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Liad Tadmor, Enrico Brusaterra, Eldad Bahat Treidel, Frank Brunner, Nicole Bickel, Sofie S. T. Vandenbroucke, Christophe Detavernier, Joachim Wuerfl, Oliver Hilt
Summary: This work investigates the properties and robustness of post metallization annealed Al2O3 atomic layers on n-type GaN in terms of chemical, physical, and electrical aspects. The study demonstrates a gate-first process flow with subsequent ohmic contact formation at temperatures up to 600 degrees C using planar metal insulator capacitors. The results show no new bonds or crystallization in the Al2O3 layer due to annealing, but degradation is observed at 600 degrees C. The annealing temperature affects the oxide depletion and deep depletion capacitances, resulting in a reduction of the flat band voltage to zero.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2023)
Article
Optics
Pooja Thakkar, Clement Fleury, Gerald Stocker, Florian Dubois, Thang Duy Dao, Reyhaneh Jannesari, Parviz Saeidi, Gerald Puehringer, Thomas Ostermann, Thomas Grille, Bernhard Jakoby, Andreas Tortschanoff, Cristina Consani
Summary: Non-dispersive infrared (NDIR) absorption spectroscopy is a widely used method for gas sensing due to its selectivity and conceptual simplicity. The design and fabrication of microstructures, specifically waveguides, that can combine high sensitivity with ease of integrability of other sensor elements is a major challenge for fully integrated NDIR sensors. In this study, we investigate a class of coupled strip-array (CSA) waveguides on a SiO2/Si3N4 platform, fabricated using mass semiconductor processes, and demonstrate their comparable sensitivity for various geometries, making it a promising platform for meeting multiple sensor and fabrication requirements without sacrificing performance.
Article
Engineering, Electrical & Electronic
Gao Zhan, Fabiana Rampazzo, Carlo De Santi, Mirko Fornasier, Gaudenzio Meneghesso, Matteo Meneghini, Herve Blanck, Jan Gruenenpuett, Daniel Sommer, Ding Yuan Chen, Kai-Hsin Wen, Jr-Tai Chen, Enrico Zanoni
Summary: DC characteristics of AlGaN/GaN HEMTs with different thickness values of the undoped GaN channel layer were compared. An abnormal transconductance (gm) overshoot accompanied by a negative threshold voltage (V-TH) shift was observed during IDS-V-GS sweep in devices with thinner GaN layer. At the same time, a non-monotonic increase in gate current was observed. In OFF-state, electron trapping occurs in the undoped GaN layer or at the GaN/AlN interface, leading to a positive VTH shift. When the device is turning on at a sufficiently high V-DS, electron de-trapping occurs due to trap impact-ionization; consequently, V-TH and therefore ID suddenly recovers, leading to the gm overshoot effect. These effects are attributed to electron trap impact-ionization and consequent modulation of the device's electric field.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Materials Science, Multidisciplinary
Nicola Trivellin, Francesco Piva, Davide Fiorimonte, Matteo Buffolo, Carlo De Santi, Enrico Zanoni, Gaudenzio Meneghesso, Matteo Meneghini
Summary: This study reports on the reliability of commercial ultraviolet-C (UV-C) light-emitting diodes (LEDs) under constant current stress. Electrical, optical, and spectral analyses were conducted on UV-C LEDs with a peak emission at 275 nm and a nominal power of 12 mW at 100 mA. Degradation tests were performed at maximum rated current, double the maximum, and three times the maximum. The results show that LED lifetime is inversely proportional to the stress current density, potentially due to high-energy electrons from Auger-Meitner recombination.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Editorial Material
Materials Science, Multidisciplinary
Michael Kneissl, Juergen Christen, Axel Hoffmann, Bo Monemar, Tim Wernicke, Ulrich Schwarz, Asa Haglund, Matteo Meneghini
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Engineering, Electrical & Electronic
Nicola Modolo, Carlo De Santi, Giulio Baratella, Andrea Minetto, Luca Sayadi, Sebastien Sicre, Gerhard Prechtl, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: Ideally, the emission profile in semiconductors should follow a pure exponential decay, but complex devices often exhibit a strongly stretched exponential shape. Conventional methodologies for mapping capture/emission time constants may lead to inaccuracies. In this article, a new methodology based on the double inverse Laplace transform is introduced to accurately extract the capture-emission time map of defects. The proposed approach is compared with conventional approximations, providing insight into the accuracy of simplified methods. The method is tested on custom-generated functions and successfully applied to extract the capture/emission time map from a power GaN HEMT subjected to positive bias instability test.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Sarah Risquez, Sebastian Redolfi, Clement Fleury, Matthias Wulf, Ali Roshanghias, Adrien Piot, Jeremy Streque, Kerstin Schmoltner, Thang Duy Dao, Markus Puff, Mohssen Moridi
Summary: This paper reports the integration of a non-CMOS transition metal oxide composite thin film with a high negative temperature coefficient resistance (NTCR) on a silicon nitride membrane for uncooled infrared microbolometer. The NTC thin film is fabricated by a chemical solution process requiring high crystallization temperature (>750 degrees C). Silicon-nitride membrane-supported bolometers with different pixel sizes (1, 2x2, and 4x4) are successfully fabricated and packaged in a vacuum-shielded TO housing. The fabricated devices exhibit a low noise equivalent temperature difference (NETD) value and a high specific detectivity.
2023 IEEE 36TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS, MEMS
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Takashi Sasaki, Adrien Piot, Anton Lagosh, Clement Fleury, Markus Bainschab, Yanfen Zhai, Marcus Baumgart, Sara Guerreiro, Dominik Holzmann, Ales Travnik, Mohssen Moridi
Summary: This paper presents a technique for reinforcing two-dimensional resonant scanning mirrors from the backside. The backside reinforcement patterns are generated based on the product of surface stress and distance from the rotation axis, and the patterns are combined for both axes. Through inhouse fabrication, piezoelectrically actuated two-dimensional micromirrors can achieve backside reinforcement of any desired thickness. Experimental results demonstrate a reduction of more than 50% in deformation for torsion mode and 40% for rocking mode, with a minimal increase in moment of inertia: 3% and 9% respectively.
2023 IEEE 36TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS, MEMS
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Takashi Sasaki, Adrien Piot, Jaka Pribosek, Anton Lagosh, Clement Fleury, Markus Bainschab, Yanfen Zhai, Marcus Baumgart, Sara Guerreiro, Dominik Holzmann, Ales Travnik, Mohssen Moridi
Summary: This paper presents a piezoelectrically actuated micromirror capable of actively controlling dynamic deformation. The proposed approach enables a reduction in dynamic deformation without increasing moment of inertia, a first in the field. A 75% reduction in dynamic deformation at the center of the mirror was calculated, and dynamic mirror shape correction was experimentally verified on fabricated devices.
2023 IEEE 36TH INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS, MEMS
(2023)
Article
Computer Science, Information Systems
Alexander Herzog, Simon Benkner, Babak Zandi, Matteo Buffolo, Willem D. Van Driel, Matteo Meneghini, Tran Quoc Khanh
Summary: This study reports on the degradation mechanisms and dynamics of silicone encapsulated high-power ultraviolet A (UV-A) light-emitting diodes (LEDs) with a peak wavelength of 365 nm. Stress tests were conducted for 8665 hours at forward currents ranging from 350 mA to 700 mA and junction temperatures up to 132 degrees C. The results showed a significant decrease in optical power, with faster degradation at higher operating conditions. The degradation mechanisms were analyzed, and a degradation model was proposed to estimate the device lifetime under different operating parameters. Additional stress test data was used to validate the accuracy of the model's lifetime predictions.
Article
Biochemical Research Methods
Florian Pilat, Benedikt Schwarz, Bettina Baumgartner, Daniela Ristanic, Hermann Detz, Aaron M. M. Andrews, Bernhard Lendl, Gottfried Strasser, Borislav Hinkov
Summary: Quality control of liquids plays a crucial role in analytical chemistry, and the gold standard for measuring residual water in organic solvents and pharmaceutical applications is Karl Fischer titration. A high-performance lab-on-a-chip sensor based on mid-IR spectroscopy is proposed for real-time analysis of residual water concentration in isopropyl alcohol. Two experiments demonstrate its ability to detect water content with high sensitivity and rapid response time. The sensor achieves a limit of detection between 120 ppm and 150 ppm for the flow cell configuration and 1.5 x 10(-2)%(vol) to 19%(vol) in the in situ configuration.
Proceedings Paper
Optics
Borislav Hinkov, Florian Pilat, Mauro David, Andreas Schwaighofer, Patricia L. Souza, Laurin Lux, Bettina Baumgartner, Daniela Ristanic, Benedikt Schwarz, Hermann Detz, Aaron M. Andrews, Bernhard Lendl, Gottfried Strasser
Summary: A monolithic mid-infrared lab-on-a-chip is presented for sensitive and selective real-time spectroscopy of liquids. The state-of-the-art operation of the fingertip-sized sensor devices is demonstrated through in-situ reaction monitoring experiments and dynamical residual-water analysis in a solvent.
2022 EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION (ECOC)
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
M. Jaidl, N. Opacak, M. A. Kainz, D. Theiner, B. Limbacher, M. Beiser, M. Giparakis, A. M. Andrews, G. Strasser, B. Schwarz, J. Darmo, K. Unterrainer
Summary: This research demonstrates terahertz quantum cascade lasers implemented in defect-free ring resonators that are mounted upside-down on a silicon substrate using die-bonding technique. The devices exhibit significantly reduced threshold current densities and allow for free-running comb formation.
2022 47TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES (IRMMW-THZ 2022)
(2022)
Article
Engineering, Electrical & Electronic
Zhiqiang Wang, Siyang Dai, Yao Zhao, Guofeng Li, Bing Ji, Volker Pickert, Bowen Gu, Shuai Ding
Summary: This paper proposes a lumped-charge model for IEGT single chip, considering the effect of carrier injection enhancement in the emitter. The parasitic inductance of the parallel branches in PP-IEGT is extracted using Ansys simulation, and the validity of Ansys simulation is verified. Furthermore, the switching inconsistency is evaluated by combining the electrical model and the effect of mutual inductance, and it is found that mutual inductance is an important factor influencing electrical parameter distribution.
MICROELECTRONICS RELIABILITY
(2024)
Article
Engineering, Electrical & Electronic
Sankha Subhra Ghosh, Surajit Chattopadhyay, Arabinda Das, Nageswara Rao Medikondu, Abdulkarem H. M. Almawgani, Adam R. H. Alhawari, Sudipta Das
Summary: This article describes a method for identifying the IGBT switch breakdown failure in a 3-phase, 3-level Voltage Source Converter linked to the photovoltaic grid. Comparative learning has been used to detect the specific parameter suitable for the detection of the failure.
MICROELECTRONICS RELIABILITY
(2024)
Article
Engineering, Electrical & Electronic
Milad Khajehvand, Henri Seppanen, Panthea Sepehrband
Summary: Using SEM/EDX analysis, microscale fracture at the bond-pad is detected during the wedge bonding process of Cu wire to a Cu or Al substrate. It is observed that the fracture of the bond leads to the formation of a bulge on the wire and a cavity in the substrate, causing fracture in the original substrate. 3D optical profiler reveals that the depth, radius, and surface area of the cavity increase with bond time for a constant bond force and power. These metrics are suggested as new factors for optimizing the wedge bonding process. The optimal bonding parameters should maximize the cavity's surface area (related to bond's pull force) while minimizing the cavity's depth relative to the substrate's thickness to avoid substrate damage. Furthermore, Molecular Dynamics simulations propose a potential plastic deformation mechanism for bond-pad damage, suggesting the benefits of using a small-grain-sized substrate, low transducer's vibration amplitude, and high transducer's frequency to minimize the cavity's depth.
MICROELECTRONICS RELIABILITY
(2024)