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
Engineering, Electrical & Electronic
Zuoheng Jiang, Mengyuan Hua, Xinran Huang, Lingling Li, Chengcai Wang, Junting Chen, Kevin J. Chen
Summary: In this article, the impacts of off-state gate bias on the dynamic on-resistance in p-GaN Gate high-electron-mobility transistors are investigated. It is found that more negative off-state gate bias can worsen the degradation of dynamic on-resistance, especially when switching with a high drain bias. The influences of off-state gate bias on switching transients and off-state stress are explored to reveal the underlying mechanisms.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Hongkeng Zhu, Elison Matioli
Summary: Accurate characterization of dynamic ON-resistance (R-ON) degradation is crucial for predicting conduction losses in GaN high-electron-mobility transistors. However, inconsistent results of dynamic R-ON based on pulsed measurements are reported in the literature, even for the same device. This study reveals that insufficient test time can lead to spurious dynamic R-ON results and contradictory conclusions. The proposed steady-state method using a hard-switching half-bridge with an active measurement circuit overcomes these challenges and enables accurate measurements of R-ON.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Yi Zhang, Cai Chen, Yue Xie, Teng Liu, Yong Kang, Han Peng
Summary: This article proposes a high-efficiency adaptive method for dynamically adjusting the dead time of GaN inverters to accommodate different operating conditions. The improved model allows for accurate dead time adjustment without the need for additional sensors. Experimental results demonstrate that the dynamic adjustment method significantly reduces power loss.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Computer Science, Information Systems
Wei Wang, Yan Liang, Minghui Zhang, Fang Lin, Feng Wen, Hongxing Wang
Summary: The study investigates the dynamic on-resistance (R-ON) behavior of a commercial GaN HEMT device with p-GaN gate under hard-switching conditions. Results show non-monotonic performance of dynamic R-ON with off-state voltage ranging from 50 to 400 V, attributed to the leaky dielectric model. The highest normalized R-ON value of 1.22 appears at 150 and 200 V. The device shows gradual increase and maximum of dynamic R-ON under prolonged stress time, due to longer trapping time related to deep acceptors and donors, with no obvious degradation at higher V-DS. The dynamic R-ON is insensitive to frequency, with leakage under source and drain contact identified as a key issue in resistance degradation.
Article
Chemistry, Multidisciplinary
Can Zou, Zixuan Zhao, Mingjun Xu, Xingfu Wang, Qing Liu, Kai Chen, Longfei He, Fangliang Gao, Shuti Li
Summary: To address the issue of minority carrier storage time in bipolar transistors, a hot electron transistor (HET) has been proposed. This device offers high working speed and the ability to perform complex logic functions with just one component. A mixed-dimensional HET composed of GaN/AlN microwires, graphene (Gr), and Si has been demonstrated, which achieves high speed hot electrons by injecting electrons between GaN/AlN into graphene through F-N tunneling mechanism, allowing for ballistic transport and collection through low-barrier Si. The device exhibits a record DC gain of 16.2, collection efficiency close to the limit of 99.9% based on GHET, emitter current density of 68.7 A/cm2, high on/off current ratio of approximately 107, and wide current saturation range, making it suitable for potential applications as a power amplifier.
Article
Computer Science, Information Systems
Wei Lin, Maojun Wang, Haozhe Sun, Bing Xie, Cheng P. Wen, Yilong Hao, Bo Shen
Summary: This paper proposes an HEMT structure with a source-connected p-GaN embedded in a carbon-doped semi-insulating buffer to suppress the buffer-induced current collapse effect. Two-dimensional transient simulation demonstrates the successful suppression of current collapse in SCPG-HEMTs compared to conventional HEMTs. The mechanism of ejecting holes from SCPG into the high resistive buffer layer after off-state stress is illustrated to potentially solve the buffer-induced degradation of dynamic on-resistance in GaN power devices.
Article
Chemistry, Multidisciplinary
Enrique Maset, Pedro Martin-Holgado, Yolanda Morilla, David Gilabert, Esteban Sanchis-Kilders, Pedro J. Martinez
Summary: This study investigates the effect of gamma irradiation and temperature on the dynamic on-resistance (R-ON) behavior of commercial GaN-on-Si power HEMTs. The results show that gate voltage bias stress contributes to the degradation of dynamic R-ON during irradiation, and temperature accelerates this degradation. Additionally, a partial reduction in dynamic R-ON is observed when the total ionizing dose is around 140 krad(SiO2) and the base temperature during irradiation is not high.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Electrical & Electronic
Xiangdong Li, Jiahui Yuan, Hongyue Wang, Zongqi Cai, Weiheng Shao, Yiqiang Chen, Xuefeng Zheng, Jincheng Zhang, Yue Hao
Summary: This work investigates the thermo-electro multiphysics coupling failure of GaN HEMTs under high-power microwave pulse stress. It is found that at low power injection, the peak temperature is located at the gate-drain access region, while at high power injection, the hot spot is found in the gate-source access region, overlapping with the electric field concentration.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Mohammad Sajid Nazir, Pragya Kushwaha, Ahtisham Pampori, Sheikh Aamir Ahsan, Yogesh Singh Chauhan
Summary: In this work, a phenomenological cryogenic model for GaN HEMTs is proposed and validated with experimental characterization results. The model accurately captures the negative threshold voltage shifts and kink effects observed at cryogenic temperatures. The impact of temperature, impact ionization, and field-dependent trapping/detrapping on performance is explored and implemented in the model to explain these phenomena.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Automation & Control Systems
Aaron Wadsworth, Matthew G. S. Pearce, Duleepa J. Thrimawithana
Summary: This article presents the design of a cryogenic gallium nitride (GaN) enhancement mode high-electron-mobility transistor (E-HEMT) synchronous buck converter, which achieves high efficiency and uses a nanocrystalline filter inductor within the cryogenic environment. The article also evaluates the selection of magnetic materials and litz wire at cryogenic temperatures. Cryogenically cooling the GaN switches reduces their losses by half compared to operating at room temperature under the same conditions.
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Pengfei Wan, Jianqun Yang, Hao Jiang, Yuanting Huang, Ling Lv, Lei Dong, Xiaoqing Yue, Bin Zhang, Gang Lin, Guojian Shao, Weiqi Li, Xiaodong Xu, Xiuhai Cui, Xingji Li
Summary: This article investigates the synergistic radiation effects on AlGaN/GaN high electron mobility transistors (HEMTs) under different irradiation conditions. The results show that HEMTs have excellent resistance to ionization radiation, but the drain current and carrier mobility decrease significantly under proton irradiation. The degradation rate caused by combined irradiation is three times higher than that caused by individual proton irradiation, indicating a synergistic effect between ionization and displacement effects.
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
(2022)
Article
Engineering, Electrical & Electronic
Pragyey Kumar Kaushik, Sankalp Kumar Singh, Ankur Gupta, Ananjan Basu
Summary: This article investigates the effect of low gate bias on R-L in a small-signal model and shows that channel resistance has strong bias dependence. It is observed that R-L dominates above the threshold voltage and yields significant changes in drain-to-source resistance and capacitance. Matching the intrinsic Y-parameter, R-L is found to be important, with good agreement between simulated and measured S-parameters data up to 40 GHz.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Materials Science, Multidisciplinary
V. Hemaja, D. K. Panda
Summary: An n-polar GaN MIS-HEMT based biosensor is proposed for label-free detection of various bio-molecules by immobilizing the analytes in the underlap region to alter the electrostatic properties of the device, resulting in a significant increase in drain current and output conductance with the addition of different biomolecules in the nanocavity, with a maximum shift in threshold voltage observed for uricase due to its low dielectric constant.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
M. Florovic, J. Kovac, A. Chvala, J. -c. Jacquet, S. L. Delage
Summary: In this article, pinch-off voltage biasing was used for the first time to determine the average channel temperature of the AlGaN/GaN HEMT, excluding the device's electrical parameters dependence in the linear operating mode. The theoretical part focused on the thermal model with temperature-dependent thermal resistance to determine the average temperature of the HEMT under quasi-static operation. The experimental part discussed the appropriate methods for determining the active area average temperature using constant isothermal saturation current or short-pulse current.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Pavan Vudumula, Thibault Cosnier, Olga Syshchyk, Benoit Bakeroot, Stefaan Decoutere
Summary: This paper presents the TCAD-based design and verification of a 200 V GaN-on-SOI integrated circuits platform, which includes depletion-mode MIS-HEMTs and Gated-Edge-Termination Schottky barrier diodes (GET-SBDs). The platform also consists of low-voltage analog/logic devices and passive components to support the GaN ICs. Device simulations were validated through measurements of low voltage test structures, resulting in calibration of various parameters for HEMT and GET-SBD structures.
SOLID-STATE ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Shun-Wei Tang, Benoit Bakeroot, Zhen-Hong Huang, Szu-Chia Chen, Wei-Syuan Lin, Ting-Chun Lo, Matteo Borga, Dirk Wellekens, Niels Posthuma, Stefaan Decoutere, Tian-Li Wu
Summary: The gate current characteristics in AlGaN/GaN high electron mobility transistors (HEMTs) with a p-GaN gate were investigated to explain the threshold voltage shift. The intrinsic gate current conduction mechanisms were identified as thermionic emission (TE) in the AlGaN/GaN region at low bias range (2.5 V < V-G < 4 V) and trap-assisted tunneling (TAT) in the Schottky/p-GaN region at higher bias range (4 V < V-G < 7 V). The threshold voltage shift in the stress phase was found to be consistent with a trap level having an activation energy of E-A similar to 0.6 eV. A physical model considering TAT via hole transport was proposed to explain the negative V-TH shift.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Sarah Tonello, Tiziano Fapanni, Stefano Bonaldo, Giada Giorgi, Claudio Narduzzi, Alessandro Paccagnella, Mauro Serpelloni, Emilio Sardini, Sandro Carrara
Summary: In recent years, there has been increasing interest in wearable devices for continuous monitoring of biochemical profiles in patients and athletes, with lactate being one of the most interesting markers for studying fatigue processes. This study proposes a new, low-cost, rapid, and flexible electrochemical amperometric lactate carbon biosensor fabricated using aerosol jet printing (AJP). The biosensors were combined with a paper-based microfluidic system and chitosan-based stable functionalization for long-term continuous monitoring of human activities. The sensor performances were evaluated through static and dynamic electrochemical tests, showing promising results for the development of standalone wearable patches for noninvasive lactate measurements.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2023)
Article
Computer Science, Information Systems
Stefano Bonaldo, Serena Mattiazzo, Marta Bagatin, Alessandro Paccagnella, Giovanni Margutti, Simone Gerardin
Summary: The total ionizing dose sensitivity of planar 150 nm CMOS technology was evaluated by measuring the DC responses of nMOSFETs at different irradiation steps. The TID sensitivities varied for transistors with different channel dimensions and operating voltages. The experimental results showed a strong relationship between TID sensitivity and the doping profiles in the channel. I/O transistors exhibited the highest TID sensitivity, while transistors designed for low-leakage applications showed near insensitivity to TID.
Article
Physics, Applied
Zequan Chen, Abhishek Mishra, Aditya K. Bhat, Matthew D. Smith, Michael J. Uren, Sandeep Kumar, Masataka Higashiwaki, Martin Kuball
Summary: The frequency dispersion of impedance in lateral beta-Ga2O3 MOSFETs has been studied and a model has been developed to explain the phenomenon. The dispersion is caused by the resistive and capacitive coupling between the terminal contact pads and the buried conducting layer at the unintentionally-doped epitaxy/substrate interface, which also leads to a buried parallel leakage path. It is shown that the dispersion is not related to gate dielectric traps, as commonly assumed. A generalized equivalent circuit model is proposed to explain the experimental results.
APPLIED PHYSICS EXPRESS
(2023)
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
Engineering, Electrical & Electronic
Marta Bagatin, Simone Gerardin, Alessandro Paccagnella, Alessandra Costantino, Veronique Ferlet-Cavrois, Anastasia Pesce, Silvia Beltrami
Summary: This study investigates the heavy-ion single event effect (SEE) response of 3-D NAND flash memory cells with charge-trap-based replacement gate technology. It discusses the error cross sections, threshold voltage shifts, and underlying mechanisms. The behavior of the RG cells is compared with previous generations of flash NAND memory cells with floating-gate architecture, both planar and 3-D. The study also examines the cell array structure, technology parameters, and materials affecting radiation susceptibility of different cell types.
IEEE TRANSACTIONS ON NUCLEAR SCIENCE
(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)
Article
Engineering, Electrical & Electronic
Akhil S. Kumar, Michael J. Uren, Justin Parke, H. George Henry, Robert S. Howell, Martin Kuball
Summary: Multichannel RF power amplifiers provide high frequency operation, high current and RF power, and excellent linearity. By using 3D and 2D simulations, the impact of device architecture on linearity and off-state reliability can be investigated, leading to an improved linear design without compromising reliability. Linearity is assessed using a 2D approximation which is computationally efficient, while off-state reliability is evaluated using a full 3D simulation to measure peak electric field. The study suggests that introducing channel number-dependent doping can enhance transconductance-linearity, and increasing gate dielectric thickness or fin width leads to a strong increase in third order intercept, while maintaining reliability requires increased fin height to reduce electric field.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Alessandro Caria, Carlo De Santi, Matteo Buffolo, Marco Nicoletto, Xuanqi Huang, Houqiang Fu, Hong Chen, Yuji Zhao, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: The aim of this article is to investigate the degradation mechanisms of GaN solar cells under harsh conditions, specifically forward current stress. The results indicate that the main parameters of the cells decrease under this stress, and there is a correlation between the charge distribution inside the active region and the concentration of trap states. The decrease in power conversion efficiency is attributed to a redistribution of charge in the active region, resulting in an increase in midgap states density. These findings fill the gap in the literature regarding the long-term reliability of GaN solar cells under harsh conditions.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(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)
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.
