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
Yan Wang, Wenhao Zheng, Shuman Mao, Bo Yan, Qingzhi Wu, Yuehang Xu
Summary: This study investigates the degradation of flexible AlGaN/GaN HEMTs under bending tensile strain for the first time. The traps locations were identified and characterized, and the results have important implications for further application of GaN technology in flexible electronics.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Seiya Kawasaki, Takeru Kumabe, Yuto Ando, Manato Deki, Hirotaka Watanabe, Atsushi Tanaka, Yoshio Honda, Manabu Arai, Hiroshi Amano
Summary: This study investigated the effects of junction capacitance and current density on the oscillation characteristics of GaN single-drift-region (SDR) impact ionization avalanche transit-time (IMPATT) diodes. GaN p(+)-n abrupt junction diodes with diameters of 200, 150, and 100 μm, and a depletion layer width of 2 μm were used. The fabricated diodes exhibited avalanche breakdown at 315 V and pulsed microwave oscillation with a peak output power exceeding 30 dBm. The oscillation frequency varied depending on junction diameter and current density, ranging from 8.56 to 21.1 GHz.
IEEE ELECTRON DEVICE LETTERS
(2023)
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
Steffan Gwyn, Scott Watson, Thomas Slight, Martin Knapp, Shaun Viola, Pavlo Ivanov, Weikang Zhang, Amit Yadav, Edik Rafailov, Mohsin Haji, Kevin E. Doherty, Szymon Stanczyk, Szymon Grzanka, Piotr Perlin, Stephen P. Najda, Mike Leszczyski, Anthony E. Kelly
Summary: This study reports on the characterization and analysis of a GaN-based DFB-LD centered at a wavelength of 420 nm, comparing it with FP devices at 450 nm and 520 nm. The DFB showed lower damping rate and parasitic capacitance, higher modulation efficiency, and potential for communications applications. Additionally, the spectral linewidth of a GaN DFB was measured for the first time in this study.
IEEE PHOTONICS JOURNAL
(2021)
Article
Engineering, Electrical & Electronic
Luke Yates, Brendan P. Gunning, Mary H. Crawford, Jeffrey Steinfeldt, Michael L. Smith, Vincent M. Abate, Jeramy R. Dickerson, Andrew M. Armstrong, Andrew Binder, Andrew A. Allerman, Robert J. Kaplar
Summary: This article details the growth and fabrication methods for developing large-area vertical GaN p-n diodes, which have gained significant interest for their high-voltage blocking and high-power efficiency capabilities. Experimental results show that these diodes exhibit high breakdown voltage and low on-resistance.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Computer Science, Information Systems
Alberto Maria Angelotti, Gian Piero Gibiino, Corrado Florian, Alberto Santarelli
Summary: A comprehensive experimental methodology based on multi-bias large-signal transient measurements is proposed for characterizing charge-trapping dynamics in modern GaN HEMT technology. This approach provides rich feature extraction and a complete basis for measurement-based compact modeling.
Article
Engineering, Electrical & Electronic
Tolen Nelson, Prakash Pandey, Daniel G. Georgiev, Michael R. Hontz, Andrew D. Koehler, Karl D. Hobart, Travis J. Anderson, Adrian Ildefonso, Raghav Khanna
Summary: This work examines a new hybrid edge termination structure for vertical GaN diodes. The hybrid structure consists of superimposed guard rings onto a junction termination extension, resulting in zones with alternating implantation depths. By optimizing the geometry design, it achieves a high breakdown voltage response while minimizing computational cost.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Chemistry, Multidisciplinary
Tuba Sarwar, Can Yaras, Xiang Li, Qing Qu, Pei-Cheng Ku
Summary: This study demonstrated a wafer-thin chip-scale portable spectrometer based on a reconstructive algorithm, suitable for wearable applications. By applying local strain engineering in InGaN/GaN multiple quantum well heterostructures, 16 spectral encoders were successfully monolithically integrated on a chip area of 0.16 mm2. The use of a non-negative least-squares algorithm achieved decent spectral reconstruction performance in the wavelength range of 400-645 nm.
Article
Engineering, Electrical & Electronic
Long Hu, Jia Huang, Xianghong Yang, Xin Shen, Yue Sun
Summary: The operation mechanism of a gallium nitride (GaN) photoconductive semiconductor switch (PCSS) based on a semi-insulating (SI) wafer was analyzed using a physics-based numerical simulation. The study found that the switch can achieve quasi-avalanche mode and ultrafast switching under specific bias conditions, which is consistent with experimental results. The physics of multiple powerful avalanche domains and their connection to the negative differential mobility (NDM) of electrons were discussed.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Physics, Multidisciplinary
Mei-Ling Zeng, Yang Wang, Xiang-Liang Jin, Yan Peng, Jun Luo
Summary: This paper reports on the photocapacitance effect and frequency scattering phenomenon of silicon-based single-photon avalanche diodes (SPADs). The test results using the small-signal capacitance-voltage method show that light can increase the capacitance of SPAD devices under low-frequency conditions, and the photocapacitance exhibits frequency-dependent characteristics. The study attributes these results to interfacial traps formed by Si-SiO2 in the devices fabricated using the standard bipolar-CMOS-DMOS process, and suggests that illumination can effectively reduce the lifetime of interfacial traps, causing changes in the junction capacitance inside the SPAD. The paper also proposes an equivalent circuit model considering the photocapacitance effect. Accurate analysis of the capacitance characteristics of SPADs is of great scientific significance and application value for studying the energy level distribution of device interface defect states and improving the interface quality.
Article
Engineering, Electrical & Electronic
Minkyu Cho, Zhiyu Xu, Marzieh Bakhtiary-Noodeh, Hoon Jeong, Chuan-Wei Tsou, Theeradetch Detchprohm, Russell D. Dupuis, Shyh-Chiang Shen
Summary: This study reports high-performance homojunction GaN avalanche photodiodes grown on a low-defect GaN substrate and fabricated with an ion-implantation isolation method. The fabricated GaN APDs showed ultralow dark current density and high photocurrent gain under deep-ultraviolet illumination. Temperature-dependent study indicated a trap-assisted tunneling process predominates the leakage current near the avalanching breakdown.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Physics, Applied
Tianhao Jiang, Jian Wang, Jiaqi Liu, Meixin Feng, Shumeng Yan, Wen Chen, Qian Sun, Hui Yang
Summary: Semiconductor nano-membranes offer a new approach to improve the performance of optical devices. In this study, we present a fabrication method for GaN-based LED membranes, which includes the complete device structure including contact metals from Si substrate. The method involves electrochemical etching of the highly conductive AlN/Si interface, which is naturally formed in GaN-on-Si materials. Photoluminescence and Raman scattering spectra show reduced internal stress, and electrical measurements demonstrate decreased leakage current and series resistance, indicating the successful preservation of the whole structure.
APPLIED PHYSICS EXPRESS
(2022)
Article
Physics, Applied
Seiya Kawasaki, Yuto Ando, Manato Deki, Hirotaka Watanabe, Atsushi Tanaka, Shugo Nitta, Yoshio Honda, Manabu Arai, Hiroshi Amano
Summary: This study presents the first experimental demonstration of microwave oscillation in GaN IMPATT diodes at the X-band, showing low leakage current, clear avalanche breakdown, and high avalanche capability. Microwave testing conducted in an X-band waveguide circuit resulted in oscillations at 9.52 GHz with a power of around 56 mW.
APPLIED PHYSICS EXPRESS
(2021)
Article
Engineering, Electrical & Electronic
Jia-Hong Lin, Fong-Min Ciou, Ting-Chang Chang, Yu-Shan Lin, Jui-Tse Hsu, Fu-Yuan Jin, Kai-Chun Chang, Ting-Tzu Kuo, Kuan-Hsu Chen, Yang-Hao Hung, Yu-Zhe Zheng
Summary: This study investigates the threshold voltage (V-T) degradation mechanism for AlGaN/GaN high electron mobility transistors under hot electron stress (HES) in semi-ON state conditions. The experimental results show that V-T shifts in the positive direction after the stress and continues to shift even after recovery. Comparing with a negative bias stress (NBS) experiment, it is found that hole recombination in pre-existing buffer defects is crucial. Therefore, a comprehensive model of V-T degradation mechanism is proposed and validated through experiments and simulations.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Marco Nicoletto, Alessandro Caria, Carlo De Santi, Matteo Buffolo, Xuanqui Huang, Houqiang Fu, Hong Chen, Yuji Zhao, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: In this article, we extensively investigate the degradation of gallium nitride (GaN)-based high periodicity indium GaN (InGaN)-GaN multiple quantum well (MQW) solar cells under optical stress at high excitation intensity and high temperature. The obtained results suggest that the degradation originates from the diffusion of hydrogen, and the proposed analytical methodology provides insight into MQW solar cell degradation.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(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
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
Energy & Fuels
Marco Nicoletto, Alessandro Caria, Fabiana Rampazzo, Carlo De Santi, Matteo Buffolo, Giovanna Mura, Francesca Rossi, Xuanqui Huang, Houqiang Fu, Hong Chen, Yuji Zhao, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: This study investigates the influence of V-pits on the electrical performance of high periodicity InGaN-GaN multiple quantum wells solar cells. Through combined electrical analysis, microscopy investigation, and simulations, it is found that V-pits can affect the turn-on voltage and current-voltage characteristics of the solar cells. The presence of V-pits allows for a closer connection between the quantum well region and the p-side contact. These findings provide insight into the role of V-pits in the electrical performance of high-periodicity quantum well devices.
IEEE JOURNAL OF PHOTOVOLTAICS
(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
Alessandro Caria, Carlo De Santi, Marco Nicoletto, Matteo Buffolo, Xuanqi Huang, Houqiang Fu, Hong Chen, Yuji Zhao, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: GaN-based multi-quantum wells solar cells have potential for extreme applications. In this study, we performed stress experiments on samples to investigate degradation mechanisms. Results showed that increased current led to changes in resistance and decreased efficiency. Measurements also revealed the generation of defects and correlated variations in charge density and conversion efficiency. These defects may migrate through the devices, as detected at different times by different measurements.
GALLIUM NITRIDE MATERIALS AND DEVICES XVIII
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Marco Nicoletto, Alessandro Caria, Carlo De Santi, Matteo Buffolo, Xuanqi Huang, Houqiang Fu, Hong Chen, Yuji Zhao, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: This study investigates the degradation of high-periodicity GaN-based InGaN-GaN multiple quantum wells (MQWs) solar cells under stress conditions. The findings suggest the presence of a thermally-activated diffusion process of impurities that increases the SRH recombination rate. By analyzing the time-variation of non-radiative Shockley-Read-Hall lifetime, the diffusion coefficient and activation energy of the defect involved in the degradation are determined.
GALLIUM NITRIDE MATERIALS AND DEVICES XVIII
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
F. Piva, M. Buffolo, C. De Santi, M. Pilati, N. Roccato, A. Muhin, N. Susilo, D. Hauer Vidal, L. Sulmoni, T. Wernicke, M. Kneissl, G. Meneghesso, E. Zanoni, M. Meneghini
Summary: The market for ultraviolet (UV) light emitting diodes (LEDs) is expected to grow due to their disinfection properties, but a thorough study of the reliability-limiting processes is needed. This study investigates the degradation mechanisms of AlGaN-based UV single quantum well (SQW) LEDs, revealing increased subthreshold leakage currents and decreased optical output power as major causes of degradation. C-DLTS measurements identify three defects, including one with an activation energy of 700 meV, suggesting gallium vacancies or nitrogen antisites.
GALLIUM NITRIDE MATERIALS AND DEVICES XVIII
(2023)
Proceedings Paper
Engineering, Multidisciplinary
D. Favero, A. Cavaliere, C. De Santi, M. Borga, W. Goncalez Filho, K. Geens, B. Bakeroot, S. Decoutere, G. Meneghesso, E. Zanoni, M. Meneghini
Summary: For the first time, this study investigates the positive threshold voltage instability in GaN-based trench gate MOSFETs at high temperatures (150-240 degrees C). By using inverse Laplace transform, the equivalent distribution of activation energies of the traps responsible for PBTI is determined, with a peak at 0.75 eV from the conduction band of GaN. Additionally, the study demonstrates the non-monotonic trend of recovery transients, attributed to the interplay between electron and hole de-trapping from different traps in the semiconductor.
2023 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM, IRPS
(2023)
