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- 摘要
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- 实验方案
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[IEEE 2019 IEEE Conference on Power Electronics and Renewable Energy (CPERE) - Aswan City, Egypt (2019.10.23-2019.10.25)] 2019 IEEE Conference on Power Electronics and Renewable Energy (CPERE) - Thermal Performance Evaluation of 1500-VDC Photovoltaic Inverters Under Constant Power Generation Operation
摘要： A technique is described, to efficiently evaluate the reliability of an RF semiconductor device when several different mechanisms contribute simultaneously to its wearout. This is of interest for present-day GaN HEMT devices because symptoms of several simultaneous degradation mechanisms have been reported widely. The technique involves first finding DC parameters that are “signatures” of each mechanism. Then, separate DC-stress lifetests are performed to find the degradation rates for the signature parameters, at several temperatures, and the corresponding Arrhenius curves. Next, an RF-stress lifetest (with only one stress condition) is performed, while monitoring all of the signature parameters and the RF performance. This is utilized to determine the “scaling factors” between the rates of change in the DC lifetests and the rates of change in the RF application. Applying these scaling factors to the original Arrhenius curves gives an “overall” Arrhenius plot for the RF application with several different lines, for the different degradation mechanisms. The technique can be extended to further degradation mechanisms, by conducting further DC and RF lifetests while monitoring appropriate signature parameters.
关键词： semiconductor device reliability,lifetesting,gallium nitride,HEMTs,Failure analysis
更新于2025-09-19 17:13:59
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[IEEE 2019 21st International Conference on Transparent Optical Networks (ICTON) - Angers, France (2019.7.9-2019.7.13)] 2019 21st International Conference on Transparent Optical Networks (ICTON) - Applications of Single Frequency Blue Lasers
摘要： Gallium nitride (GaN) sources are becoming a regular part of today’s world and are now key devices for lighting infrastructures, communications systems and quantum applications, amongst others. In particular, many applications have seen the shift from LEDs to laser diodes to make use of higher powers, higher bandwidths and increased transmission distances. Laser communication systems are well established, however there are applications where the ability to select a single emitted wavelength is highly desirable, such as quantum atomic clocks or in filtered communication systems. Distributed feedback (DFB) lasers have been realised emitting at a single wavelength where the grating structure is etched into the sidewall of the ridge. The main motivation in developing these lasers is for the cooling of ions in atomic clocks; however their feasibility for optical communications is also explored. Narrow linewidth lasers are desirable and this paper will explore how this is achieved. Data rates in excess of 1 Gbit/s have also been achieved in a directly modulated, unfiltered system. These devices lend themselves towards wavelength division multiplexing and filtered optical communications systems and this will be analysed further in the work presented here.
关键词： gallium nitride,optical atomic clocks,optical communications,distributed feedback lasers
更新于2025-09-19 17:13:59
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Local atomic structure of the GaN-side of the Al2O3/GaN interface revealed by X-ray absorption spectroscopy
摘要： The interface between a gate insulator (Al2O3) and a semiconductor (GaN) was investigated via surface-sensitive Ga K-edge extended X-ray absorption fine structure spectroscopy, achieved by detecting the Ga LMM Auger electrons originated from the Ga K-shell absorption. This GaN-side interface study was conducted on Al2O3 thin films formed via atomic layer deposition. The determined atomic structures revealed GaN crystalline changes and the formation of Ga–O bonds due to nitrogen annealing.
关键词： Aluminum oxide (Al2O3),Interface,Post-deposition annealing (PDA),Gallium nitride (GaN),Extended X-ray absorption fine structure (EXAFS),Atomic layer deposition (ALD)
更新于2025-09-19 17:13:59
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Laser Molecular Beam Epitaxy (LMBE) Technique grown GaN p-n junction
摘要： Gallium Nitride (GaN) thin films have been prepared using Laser Molecular Beam Epitaxy (LMBE) technique at moderate growth temperature in N2 gas ambience. The structural and optical properties of the films were optimized. A p-n junction diode has been successfully realised using GaN film grown by UHV-LMBE technique and p-type Mg:GaN/Sapphire substrate. Rectifying diode characteristics with low knee voltage of 1.2V were obtained for the prepared p-n junction, highlighting the promising prospects of employing LMBE technique for the realization of GaN based LEDs.
关键词： Gallium Nitride,Laser MBE,p-n heterojunction
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Ottawa, ON, Canada (2019.7.8-2019.7.12)] 2019 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Energy Efficiency Analysis of GaN-based Superluminescent Diodes
摘要： Gallium-nitride-based superluminescent light-emitting diodes (SLEDs) are attractive light sources for augmented or virtual reality devices and other applications. However, the energy efficiency of SLEDs is still far below the peak values reported for LEDs and laser diodes. Utilizing advanced numerical device simulation, this paper investigates the internal physical processes that cause the low SLED efficiency.
关键词： superluminescent light-emitting diode,Gallium Nitride,SLED,efficiency
更新于2025-09-16 10:30:52
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Transfer-Free Graphene-Like Thin Films on GaN LED Epiwafers Grown by PECVD Using an Ultrathin Pt Catalyst for Transparent Electrode Applications
摘要： In this work, we grew transfer-free graphene-like thin films (GLTFs) directly on gallium nitride (GaN)/sapphire light-emitting diode (LED) substrates. Their electrical, optical and thermal properties were studied for transparent electrode applications. Ultrathin platinum (2 nm) was used as the catalyst in the plasma-enhanced chemical vapor deposition (PECVD). The growth parameters were adjusted such that the high temperature exposure of GaN wafers was reduced to its minimum (deposition temperature as low as 600 °C) to ensure the intactness of GaN epilayers. In a comparison study of the Pt-GLTF GaN LED devices and Pt-only LED devices, the former was found to be superior in most aspects, including surface sheet resistance, power consumption, and temperature distribution, but not in optical transmission. This confirmed that the as-developed GLTF-based transparent electrodes had good current spreading, current injection and thermal spreading functionalities. Most importantly, the technique presented herein does not involve any material transfer, rendering a scalable, controllable, reproducible and semiconductor industry-compatible solution for transparent electrodes in GaN-based optoelectronic devices.
关键词： transparent electrodes,transfer-free,PECVD,LEDs,heat spreading,gallium nitride,graphene
更新于2025-09-12 10:27:22
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Dual-surface lens with ring-shaped structures for optical tuning of GaN ultraviolet photodetectors at low temperature
摘要： This study aims to enhance the optical sensitivity of gallium nitride ultraviolet (UV) photodetectors at low temperatures using a multifunctional microlens with ring-shaped structures. This dual-surface lens with ring-shaped structures (i.e., DSLR), a unique microlens, was fabricated by employing a curable polymer and three-dimensional printed mold, and it has two primary regions: An upper and a lower region. The upper region of the DSLR serves as a smooth lens surface to focus the incident UV rays by delaying frost formation at low temperatures. The lower region captures condensed water droplets, thus allowing for only local frost formation. When compared to a photodetector without the DSLR, the photodetector covered by the DSLR generated a higher photocurrent at low temperatures (corresponding to a ~13.85% increase in generated photocurrent in the temperature range of -20°C to -1.2°C). Thus, the findings of this study support the use of a facile, cost-effective, and multifunctional dual-surface polymer lens for higher-sensitivity UV detection in various low-temperature environments, such as the Arctic, outer space, and the environment within cryostats.
关键词： Photodetector,Dual-surface,Gallium nitride,Ring-shaped structures,Low temperature,Microlens
更新于2025-09-12 10:27:22
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High-Voltage AlInGaN LED Chips
摘要： A high-voltage light-emitting diode (LED) flip chip based on an AlInGaN heterostructure is developed and fabricated. The LED flip chip consists of 16 elements connected in series, each of which is a conventional LED. The chip with a total area of 1.25 × 1.25 mm is intended for a working current of 20 mA and a forward voltage of 48 V. To improve the current-distribution uniformity over the active region of the chip elements and to minimize the losses of the element area occupied by the n-type contact, the n-type contact pads in them are arranged inside the p-type contact region due to the two-level metallization layout with an intermediate insulating layer of dielectric. The arrangement topology of the contact pads is developed using numerical simulation. An increase in the quantum efficiency of the chip is provided by the application of combinations of metals with a high reflectance at the LED emission wavelength, which are used when fabricating n- and p-type contacts as well as current-carrying strips.
关键词： light-emitting diode,flip-chip design,LED chip,gallium nitride,high-voltage chip
更新于2025-09-12 10:27:22
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Integrable Quasi‐Vertical GaN UMOSFETs for Power and Optoelectronic ICs
摘要： Integrable, hexagonal-cell, high-voltage, quasi-vertical GaN power U-shaped trench-gate metal-oxide-semiconductor field-effect transistors (UMOSFETs) are experimentally demonstrated for the first time. Hexagonal cells are employed to obtain identical m-plane sidewalls for gate and drain trenches. Metallization compatible with LED optoelectronic integration is used. The dependence of device performance on different parameters is systematically studied and analyzed. The lowest Ron,sp of 23 mΩ-cm2 and highest drain saturation current of 295 A/cm2 were obtained by measuring an 11-μm cell-pitch UMOSFET. The breakdown voltage of an open-cell design variation (208 V) is higher than that of a closed-cell design variation (89 V), while the closed-cell design exhibits a lower off-state leakage current of 1.4×10-5 A/cm2. A hexagonal-cell specific on-state resistance Rcell,sp of 8.5 mΩ-cm2 and buried n+ layer sheet resistance RBL,□ of 223 Ω/□ are extracted by applying a two dimensional resistance network model to UMOSFETs of varying sizes.
关键词： hexagonal cell,array resistance network model,2D-gallium nitride,integrable quasi-vertical power UMOSFETs,gallium nitride
更新于2025-09-11 14:15:04
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Sacrificial layer for laser lift-off process for flexible-display production
摘要： In this study, we developed a new sacrificial layer (SL) for laser transfer process. Metallic substrate i.e. invar foil was temporarily docked to a glass substrate using glass powder. To ensure successful delamination, the SL was pre-deposited between metal foil and glass substrate. For the first time, the SLs were amorphous gallium nitride and non-stoichiometric gallium oxide which were implemented for laser lift off (LLO) processes of metal foil. Bonding of metal foil to glass sheet was performed using heat treatment while debonding was achieved by LLO method. The laser wavelength was 355 nm which was the best fit for full absorption from SL layers. Transmission electron microscopy, element mapping, and energy dispersive X-ray spectroscopy analyses were performed for investigating elements’ migration and bonding-debonding mechanism.
关键词： Gallium oxide,Flexible displays,Gallium nitride,Laser lift-off,Sacrificial layer
更新于2025-09-11 14:15:04