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15 pages, 2694 KB

Open AccessArticle

6–18 GHz High-Efficiency Power Amplifier MMIC Based on Broadband Impedance Matching

by Shuai Liu, Xiaohua Ma, Yi Zhang, Zhaoke Bian and Chunliang Xu

Micromachines 2026, 17(6), 690; https://doi.org/10.3390/mi17060690 - 3 Jun 2026

To meet the high standard requirements for broadband high-efficiency power amplifiers in modern communication technology, a 6–18 GHz high-efficiency monolithic microwave integrated circuit (MMIC) power amplifier was developed using a 0.25 μm gallium nitride high-electron mobility transistor (GaN HEMT) process. A multistage Chebyshev-filter-based [...] Read more.

To meet the high standard requirements for broadband high-efficiency power amplifiers in modern communication technology, a 6–18 GHz high-efficiency monolithic microwave integrated circuit (MMIC) power amplifier was developed using a 0.25 μm gallium nitride high-electron mobility transistor (GaN HEMT) process. A multistage Chebyshev-filter-based matching approach is utilized to provide the requisite bandwidth while concurrently managing second-harmonic terminations for enhanced PAE. In the final power stage, a multi-cell combining architecture is employed to achieve high saturated output power. The designed GaN amplifier achieves a saturated power of above 43.5 dBm and a PAE of over 30%. The area of the proposed GaN amplifier is 4 × 3.2 mm². This chip, with its high efficiency and compact size, is promising for high-performance wideband systems. Full article

(This article belongs to the Special Issue RF and Power Electronic Devices and Applications, 2nd Edition)

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20 pages, 15712 KB

Open AccessArticle

Decoupling and Optimization of Intrinsic Vertical Breakdown in 8-Inch GaN-on-Si HEMT Buffer

by Wei Dong, Shuhan Zhang, Qian Fan, Xianfeng Ni and Xing Gu

Electronics 2026, 15(11), 2423; https://doi.org/10.3390/electronics15112423 - 2 Jun 2026

Abstract

This study systematically investigates the intrinsic vertical breakdown characteristics of 8-inch GaN-on-Si high-electron-mobility transistor (HEMT) buffer layers (extending up to the GaN channel layer) using a vertical electrode configuration. By comparing samples with different carbon doping doses, AlN insertion layers, and superlattice cycle [...] Read more.

This study systematically investigates the intrinsic vertical breakdown characteristics of 8-inch GaN-on-Si high-electron-mobility transistor (HEMT) buffer layers (extending up to the GaN channel layer) using a vertical electrode configuration. By comparing samples with different carbon doping doses, AlN insertion layers, and superlattice cycle numbers (buffer layer thickness), combined with Technology Computer-Aided Design (TCAD) simulations, the relevant mechanisms are revealed. The results show that buffer layer thickness is a critical factor determining the vertical breakdown voltage. Its increase effectively reduces the longitudinal average electric field, widens the depletion region, and increases the breakdown voltage by approximately 50%. Carbon doping compensates for carriers and suppresses leakage through deep-level acceptor traps. Inserting thin AlN layers into the superlattice has a limited effect on improving breakdown voltage. This research provides clear experimental guidance for the optimal design of high-voltage GaN HEMT buffer layers from both material and physical perspectives. Full article

(This article belongs to the Special Issue Advances in GaN Semiconductors Technology: Materials & Devices for the Next Generation of High-Efficiency Power Electronics)

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13 pages, 2334 KB

Open AccessArticle

Characteristics of Gallium Nitride-Based Dual-Gate Metal-Oxide-Semiconductor High-Electron-Mobility Transistors with Gate Oxide Layers Directly Grown by Photoelectrochemical Oxidation Method

by Zih-Siang Hung, Hsin-Ying Lee, Ricky W. Chuang and Ching-Ting Lee

Micromachines 2026, 17(6), 645; https://doi.org/10.3390/mi17060645 - 24 May 2026

Viewed by 197

Abstract

To minimize the influence of interface states and surface damage, by inserting a gate oxide layer, the photoelectrochemical oxidation method was utilized to directly grow the gate oxide layer while simultaneously creating the gate-recessed regions onto gallium nitride (GaN)-based single-gate and dual-gate metal-oxide-semiconductor [...] Read more.

To minimize the influence of interface states and surface damage, by inserting a gate oxide layer, the photoelectrochemical oxidation method was utilized to directly grow the gate oxide layer while simultaneously creating the gate-recessed regions onto gallium nitride (GaN)-based single-gate and dual-gate metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs). Compared to the single-gate structure, the two-dimensional electron gas (2DEG) channel layer was also modulated by the auxiliary gate, in addition to being modulated by the main gate. Consequently, a wider transconductance range, larger saturation drain-source current, lower gate leakage current, and higher drain-source breakdown voltage were the benefits derived from the auxiliary gate functionality in the dual-gate devices. Moreover, the low-frequency noise characteristics of the GaN-based MOS-HEMTs could also be improved by the dual-gate structure. These experimental results demonstrated that incorporating a dual-gate structure and directly grown gate oxide layers onto GaN-based MOS-HEMTs is a promising alternative for GaN-based low-noise, high-power, and high-frequency applications. Full article

(This article belongs to the Special Issue III–V Compound Semiconductors and Devices, 2nd Edition)

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14 pages, 5301 KB

Open AccessArticle

Reinforcement Learning-Based Optimization of Ku-Band Low-Noise Amplifier

by Jiyong Chung, Hoyeon Shin, Seonho Shin, Yeonggi Kim, Saeed Zeinolabedinzadeh, Dongjin Ji and Ickhyun Song

Micromachines 2026, 17(5), 554; https://doi.org/10.3390/mi17050554 - 30 Apr 2026

Viewed by 387

Abstract

In this paper, we present a study on the automated design optimization of a wideband low-noise amplifier (LNA) operating in Ku-band (12 to 18 GHz) using proximal policy optimization (PPO), one of the widely applied reinforcement learning (RL) algorithms for engineering problems. As [...] Read more.

In this paper, we present a study on the automated design optimization of a wideband low-noise amplifier (LNA) operating in Ku-band (12 to 18 GHz) using proximal policy optimization (PPO), one of the widely applied reinforcement learning (RL) algorithms for engineering problems. As a target microwave active circuit, we select a two-stage LNA architecture, where transmission lines (TLs) are dominantly used for impedance matching and gain/noise optimization. For simplicity, all widths of TLs were fixed so that the characteristic impedance is 50 Ω, with lengths of TLs being set as design parameters. In addition, dimension variables of capacitors were treated as design parameters and, in total, we optimized 29 parameters. For target specifications, we set both

S_{11}

and

S_{22}

to be below −10 dB over the 12–18 GHz band and the noise figure (NF) to be below 2 dB. A total of 20,140 simulations were performed for training and the overall process took about 24 h. The results show that both the reward and the loss converged appropriately, achieving the target specifications successfully. For the final results, we performed up to 25 predictions, and the prediction process was terminated early if a solution meeting all target specifications was found within the given number of attempts. The device model used was a commercial 150 nm GaN high-electron-mobility transistor (HEMT) process technology. Full article

(This article belongs to the Special Issue Recent Advances in Electromagnetic Devices, 2nd Edition)

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12 pages, 12339 KB

Open AccessArticle

Terahertz Antenna-Coupled Wire-Channel Field-Effect Transistors Based on AlGaN/GaN Heterostructures

by Maxim Moscotin, Justinas Jorudas, Pawel Prystawko, Miroslav Saniuk, Vitalij Kovalevskij and Irmantas Kašalynas

Sensors 2026, 26(9), 2701; https://doi.org/10.3390/s26092701 - 27 Apr 2026

Viewed by 760

Abstract

We propose a terahertz (THz) antenna-coupled wire-channel field-effect transistor—modified EdgeFET (m-EdgeFET), formed by combining single-gate FinFET and dual-side-gate EdgeFET concepts, which is used for THz detection. The proposed hybrid design was implemented on AlGaN/GaN high-electron-mobility transistor (HEMT) structures, demonstrating distinct response characteristics under [...] Read more.

We propose a terahertz (THz) antenna-coupled wire-channel field-effect transistor—modified EdgeFET (m-EdgeFET), formed by combining single-gate FinFET and dual-side-gate EdgeFET concepts, which is used for THz detection. The proposed hybrid design was implemented on AlGaN/GaN high-electron-mobility transistor (HEMT) structures, demonstrating distinct response characteristics under 150 GHz and 300 GHz radiation at room temperature. The responsivity dependence on the channel length was determined, revealing that the peak responsivity reached up to 6.5 V/W at a gate voltage of −3 V, i.e., at a gate bias that is an order lower in magnitude than that required for EdgeFET to reach the maximum response. Meanwhile, the gate leakage current decreased by an order of magnitude (to about 1 nA) compared to a FinFET with similar geometry. The proposed geometry was shown to operate in two regimes: source-drain coupling (SD) and gate coupling (GG) of THz radiation with the transistor wire channel. The results confirm that the m-EdgeFET design is suitable for electrically controlled and fast THz detection. Full article

(This article belongs to the Section Nanosensors)

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16 pages, 7426 KB

Open AccessArticle

Mg Doping Gradient Engineering by MOCVD for Threshold Voltage Enhancement in Si-Based p-GaN E-Mode HEMTs

by Changyao Chen, Shuhan Zhang, Qian Fan, Xianfeng Ni and Xing Gu

Coatings 2026, 16(4), 476; https://doi.org/10.3390/coatings16040476 - 16 Apr 2026

Viewed by 660

Abstract

The threshold voltage (Vth) of p-GaN gate enhancement-mode (E-mode) high electron mobility transistors (HEMTs) on silicon substrates grown by metal–organic chemical vapor deposition (MOCVD) is often limited to 1.0–1.5 V. Apart from the low Mg acceptor activation rate, the non-uniform vertical Mg distribution [...] Read more.

The threshold voltage (Vth) of p-GaN gate enhancement-mode (E-mode) high electron mobility transistors (HEMTs) on silicon substrates grown by metal–organic chemical vapor deposition (MOCVD) is often limited to 1.0–1.5 V. Apart from the low Mg acceptor activation rate, the non-uniform vertical Mg distribution in thin p-GaN layers is also a key bottleneck limiting Vth. This work reveals that the vertical distribution (not only magnitude) of Mg doping fundamentally influences Vth by modulating the charge centroid and electric field coupling to the heterointerface. Through bis(cyclopentadienyl)magnesium (Cp₂Mg) flow modulation, surfactant-assisted growth, and growth rate adjustment, the vertical Mg doping uniformity within the 80 nm p-GaN layer was improved while effectively suppressing Mg out-diffusion. A short-cycle gate-first self-aligned process was used to fabricate the devices, and the results showed that the improved Mg vertical distribution led to a significant Vth enhancement by 0.75 V. Technology Computer-Aided Design (TCAD) simulations further demonstrated that the uniform doping profile builds a stronger negative space charge field beneath the gate, raising the energy band and increasing Vth. This work not only presents practical strategies, but also establishes a direct physical link between vertical Mg doping distribution and Vth in Si-based E-mode HEMTs. Full article

(This article belongs to the Special Issue Advanced Functional Nanostructured Films and Coatings for Energy Applications, 2nd Edition)

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8 pages, 3120 KB

Open AccessArticle

Improved Threshold Voltage Stability of p-GaN Gate HEMTs Under Off-State Drain Stress Using p-NiO RESURF Terminal

by Jun Pan, Xiangru Ye, Ruixi Jiang, Ailin Miao, Fuxiang Miao, Zhiyi Mao, Yanghu Peng, Hui Guo and Jianming Lei

Micromachines 2026, 17(4), 482; https://doi.org/10.3390/mi17040482 - 16 Apr 2026

Viewed by 445

Abstract

A comparative study was undertaken to examine the V_TH stability of p-GaN gate high electron mobility transistors (HEMTs) without the p-NiO reduced surface field (RESURF) terminal and with the RESURF terminal under off-state drain voltage stress and negative gate stress, involving in-depth [...] Read more.

A comparative study was undertaken to examine the V_TH stability of p-GaN gate high electron mobility transistors (HEMTs) without the p-NiO reduced surface field (RESURF) terminal and with the RESURF terminal under off-state drain voltage stress and negative gate stress, involving in-depth analyses of the net negative charge accumulation processes in the gate region and buffer layer, thereby revealing the degradation mechanisms of the devices. The findings indicate that the p-NiO RESURF terminal effectively enhances the stability of V_TH under off-state drain voltage stress by injecting holes into the buffer layer and hence initiating a light-pumping effect, and simultaneously also by flattening the electric field peak on the drain side beneath the gate and thus significantly mitigating hole loss in the gate region and electron capture in the buffer layer. This study provides a theoretical basis for the application of the p-NiO RESURF terminal in p-GaN HEMTs. Full article

(This article belongs to the Section D1: Semiconductor Devices)

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47 pages, 3812 KB

Open AccessReview

GaN HEMTs for Electric Vehicle Power Electronics: Device Architectures, Reliability and Next-Generation Wide Bandgap Opportunities

by Husna Hamza, Julie Roslita Rusli and Anwar Jarndal

Energies 2026, 19(7), 1752; https://doi.org/10.3390/en19071752 - 3 Apr 2026

Viewed by 1201

Abstract

The accelerating adoption of electric vehicles (EVs) is driving the demand for next-generation wide-bandgap (WBG) power devices that can deliver high efficiency, high power density, and robust operation under stringent electrical and thermal stress. Gallium nitride (GaN) high-electron-mobility transistors (HEMTs) have emerged as [...] Read more.

The accelerating adoption of electric vehicles (EVs) is driving the demand for next-generation wide-bandgap (WBG) power devices that can deliver high efficiency, high power density, and robust operation under stringent electrical and thermal stress. Gallium nitride (GaN) high-electron-mobility transistors (HEMTs) have emerged as a leading WBG technology due to their high breakdown voltage, ultrafast switching capability, and low conduction and switching losses relative to silicon devices, enabling high-performance EV power converters such as on-board chargers, DC-DC converters, and traction inverters. This review provides a comprehensive device-level assessment of GaN HEMTs, emphasizing advanced device architectures, state-of-the-art discrete transistors, and their implications for high-frequency, high-efficiency power conversion. Critical performance and reliability challenges, including current collapse, self-heating, and gate degradation, are analyzed in the context of their physical mechanisms and operational behavior under realistic conditions such as elevated junction temperatures, high switching frequencies, and dynamic load profiles. Furthermore, emerging opportunities in ultra-wide-bandgap semiconductor technologies beyond GaN are discussed, providing insights to guide the design, optimization, and robust integration of WBG devices into next-generation EV power electronic systems. Full article

(This article belongs to the Special Issue Next-Generation Wide Band Gap Device Architectures for Power Electronics and Renewable Energy Applications)

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18 pages, 4695 KB

Open AccessArticle

Design of GaN HEMT Buck Converter for BCM Operation

by Yueh-Tsung Hsieh, Chun-Hao Chen, Tsung-Lin Chen, Wei-Hua Chieng and Edward-Yi Chang

Energies 2026, 19(7), 1700; https://doi.org/10.3390/en19071700 - 30 Mar 2026

Viewed by 670

Abstract

Power density and power efficiency are crucial for the design of high-performance computing servers. Buck converters exist due to their simplicity, but achieving a solution that combines high efficiency and high power density remains an ongoing research area in buck converter design. High-frequency [...] Read more.

Power density and power efficiency are crucial for the design of high-performance computing servers. Buck converters exist due to their simplicity, but achieving a solution that combines high efficiency and high power density remains an ongoing research area in buck converter design. High-frequency switching, which reduces inductor size in buck converters, is a common method for achieving high power density; however, high-frequency switching introduces higher switching losses, hence the frequent use of GaN HEMTs, which have low switching losses. To achieve both high efficiency and high power density, this study proposes a compact buck converter design that pairs a D-type GaN HEMT with a low-voltage PMOS, termed a P-cascode GaN HEMT. We analyze different current switching modes and find that boundary conduction mode (BCM) can minimize inductor size while maintaining high power efficiency. This paper explores the theoretical basis of BCM and the P-cascode GaN HEMT, derives the operating conditions of BCM, estimates power efficiency, and proposes a high-power density buck converter solution. Simulation and experimental results show that the proposed design achieves 95% power efficiency in applications from 12 V to 3.3 V, while reducing the inductor size by a factor of 10 compared to continuous conduction mode (CCM) designs. Full article

(This article belongs to the Topic Power Electronics Converters, 2nd Edition)

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11 pages, 2534 KB

Open AccessArticle

Source Field Plate Incorporated Monolithic Inverters Composed of GaN-Based CMOS-HEMTs with Double-2DEG Channels and Fin-Gated Multiple Nanochannels

by Hong-You Chen, Hsin-Ying Lee, Hao Lee, Yuh-Renn Wu and Ching-Ting Lee

Materials 2026, 19(6), 1209; https://doi.org/10.3390/ma19061209 - 19 Mar 2026

Viewed by 469

Abstract

In this study, enhancement- and depletion-mode (E- and D-mode) GaN-based 120 nm-wide fin-gated multiple nanochannel metal–oxide–semiconductor high-electron-mobility transistors (MOS-HEMTs) were manufactured on the epitaxial Al_0.83In_0.17N/GaN/Al_0.18Ga_0.82N/GaN two-dimensional electron gas (2DEG) channel layers grown on Si substrates [...] Read more.

In this study, enhancement- and depletion-mode (E- and D-mode) GaN-based 120 nm-wide fin-gated multiple nanochannel metal–oxide–semiconductor high-electron-mobility transistors (MOS-HEMTs) were manufactured on the epitaxial Al_0.83In_0.17N/GaN/Al_0.18Ga_0.82N/GaN two-dimensional electron gas (2DEG) channel layers grown on Si substrates using a metal-organic chemical vapor deposition system. The oxide layer grown directly by the photoelectrochemical oxidation method was used as the gate oxide layer in D-mode MOS-HEMTs. Furthermore, E-mode MOS-HEMTs used ferroelectric stacked LiNbO₃/HfO₂/Al₂O₃ layers as the gate oxide layers. The 120 nm-wide multiple nanochannels and various-length source field plates (SFPs) were fabricated and incorporated into monolithic complementary MOS-HEMTs (CMOS-HEMTs) consisting of D- and E-mode MOS-HEMTs. The resulting monolithic unskewed inverter was achieved by modulating the drain-source current of the D-mode MOS-HEMTs. The noise low margin of 2.03 V and noise high margin of 2.10 V of the unskewed monolithic inverter were obtained. From the dynamic experimental results, the rising time and falling time of the unskewed monolithic inverter were 4.9 μs and 3.2 μs, respectively. The breakdown voltage could be improved by incorporating an SFP. When the SFP edge was located at the center between the gate electrode and the drain electrode, the maximum breakdown voltage of 855 V was obtained. Full article

(This article belongs to the Topic Wide Bandgap Semiconductor Electronics and Devices)

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32 pages, 6543 KB

Open AccessReview

MOCVD Growth of Next-Generation III–V Semiconductor Devices: In Review

by Zoya Noor, Muhammad Usman, Shazma Ali, Anis Naveed, Amina Hafeez and Ahmed Ali

Photonics 2026, 13(3), 273; https://doi.org/10.3390/photonics13030273 - 12 Mar 2026

Viewed by 4102

Abstract

Metal–organic chemical vapor deposition (MOCVD) is a crystal growth technique used to achieve high-purity thin films, especially III–V materials, for fabricating semiconductor devices. It allows for thickness tunability, controlled doping, and composition of epilayers. This review focuses on the principle of MOCVD, its [...] Read more.

Metal–organic chemical vapor deposition (MOCVD) is a crystal growth technique used to achieve high-purity thin films, especially III–V materials, for fabricating semiconductor devices. It allows for thickness tunability, controlled doping, and composition of epilayers. This review focuses on the principle of MOCVD, its historical background, and its applications in III–V semiconductor devices such as solar cells, high electron mobility transistors (HEMTs), light-emitting diodes (LEDs), laser diodes (LDs), and photonic integrated circuits (PICs). This review highlights the recent developments in MOCVD aimed at improving its efficiency, performance, and sustainability. Finally, we emphasize emerging trends and challenges in MOCVD process innovation, reactor design, and material integration that are poised to drive the development of next-generation optoelectronic, photonic, and quantum technologies. Together, these findings underscore MOCVD’s pivotal role in enabling high-performance devices and sustaining leadership in post-Moore semiconductor technologies. Full article

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9 pages, 2896 KB

Open AccessArticle

A 6–18 GHz High-Efficiency GaN Power Amplifier Using Transistor Stacking and Reactive Matching

by Cetian Wang, Xuejie Liao, Moquan Gong, Fei Xiao, He Guan, Fan Zhang and Deyun Zhou

Micromachines 2026, 17(3), 338; https://doi.org/10.3390/mi17030338 - 10 Mar 2026

Viewed by 811

Abstract

This article presents the design and implementation of a 6–18 GHz GaN monolithic microwave integrated circuit (MMIC) power amplifier (PA). A two-stage cascaded reactive matching network structure based on transistor stacking technology is employed to achieve circuit gain, and a multi-cell combination is [...] Read more.

This article presents the design and implementation of a 6–18 GHz GaN monolithic microwave integrated circuit (MMIC) power amplifier (PA). A two-stage cascaded reactive matching network structure based on transistor stacking technology is employed to achieve circuit gain, and a multi-cell combination is used in the final stage to simultaneously achieve high power and high efficiency. For demonstration, a prototype of the proposed PA with an area of 4.5 × 3.4 mm² is fabricated in a 0.1 µm GaN-on-Si high-electron-mobility transistor (HEMT) process. The measured results of the GaN PA show a small signal gain of 25–29 dB, an output power of 40.8–42.5 dBm, and a power-added efficiency (PAE) of 27–38% in the operating frequency range of 6–18 GHz. Full article

(This article belongs to the Special Issue Recent Advancements in Microwave and Optoelectronics Devices)

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13 pages, 1465 KB

Open AccessArticle

Data Augmentation via Auxiliary Classifier GAN for Enhanced Modeling of Gallium Nitride HEMT Devices

by Yifei Liu, Yihan Qian, Yefeng Hu and Ye Wu

Electronics 2026, 15(5), 1067; https://doi.org/10.3390/electronics15051067 - 4 Mar 2026

Viewed by 480

Abstract

Accurate and efficient modeling of AlGaN/GaN HEMTs is essential for the design of next-generation power electronics. This study introduces a hybrid Auxiliary Classifier Generative Adversarial Network (ACGAN)–mixup data augmentation framework to enhance deep neural network application in AlGaN/GaN high-electron-mobility transistor modeling with limited [...] Read more.

Accurate and efficient modeling of AlGaN/GaN HEMTs is essential for the design of next-generation power electronics. This study introduces a hybrid Auxiliary Classifier Generative Adversarial Network (ACGAN)–mixup data augmentation framework to enhance deep neural network application in AlGaN/GaN high-electron-mobility transistor modeling with limited data. Based on only 20 distinctive devices, ACGAN uses technology computer-aided design (TCAD)-calibrated data to generate high-quality synthetic drain current (

I_{d s}

) under various electronic bias conditions. The quality of the generated data is validated via Jensen–Shannon divergence with an average of 0.0341. A one-dimensional convolutional neural network (1D-CNN) predictive model is trained on augmented data and achieves stable convergence, with a mean absolute error of 0.002 A/mm for the off-state

I_{d s}

and 0.052 A/mm for the linear region. It also shows improved robustness over the model trained on original non-augmented data. The proposed approach offers a low-cost alternative to resource-intensive TCAD simulations, enabling accurate device modeling with limited data. Full article

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7 pages, 694 KB

Open AccessProceeding Paper

Life Cycle Assessment of Epitaxy of GaN-on-SiC High-Electron-Mobility Transistors for Advanced Radio Frequency Applications

by Max Mosig, Stefan Müller and Rüdiger Quay

Eng. Proc. 2026, 127(1), 2; https://doi.org/10.3390/engproc2026127002 - 24 Feb 2026

Viewed by 496

Abstract

From 4G to 5G to 6G, every few years, a new generation of data transmission technology emerges to meet the growing demand for faster and more efficient communication. Artificial intelligence, the Internet of Things and the increasing need for global connectivity are the [...] Read more.

From 4G to 5G to 6G, every few years, a new generation of data transmission technology emerges to meet the growing demand for faster and more efficient communication. Artificial intelligence, the Internet of Things and the increasing need for global connectivity are the key drivers of this evolution, pushing both research and industry toward ever-higher data rates. These advanced technologies already consume vast amounts of resources and energy, relying on high-tech nano-fabrication processes such as metal–organic chemical vapor deposition, dry etching, deposition and lithography, all of which typically occur in energy-intensive cleanroom environments. This study evaluates the epitaxy process of GaN on SiC for high-electron-mobility transistor (HEMT) devices and integrated circuits using life cycle assessment. GaN HEMTs offer high efficiency and excellent thermal conductivity, paving the way for reduced chip footprints for lower energy consumption. This analysis enables informed decision-making regarding sustainability by providing detailed data and interpretation of Fraunhofer IAF’s GaN-on-SiC HEMT technology. Full article

(This article belongs to the Proceedings of International Conference on Responsible Electronics and Circular Technologies)

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24 pages, 8244 KB

Open AccessEditor’s ChoiceReview

Recent Advances in Diamond-Capped GaN HEMTs for RF Application

by Yuanmeng Xiang, Mei Wu, Haolun Sun, Shiming Li, Hongda Chen, Jiamin Wei, Binyan Yan, Ling Yang, Meng Zhang, Hao Lu, Bin Hou, Xiaohua Ma and Yue Hao

Nanomaterials 2026, 16(4), 224; https://doi.org/10.3390/nano16040224 - 9 Feb 2026

Viewed by 1162

Abstract

Self-heating effects severely limit the performance of gallium nitride high-electron-mobility transistors (GaN HEMTs) in high-power radio frequency (RF) applications. Diamond capping technology leveraging diamond’s exceptional thermal conductivity (>2000 W/m·K) has emerged as a highly promising near-junction cooling solution. However, its integration with GaN [...] Read more.

Self-heating effects severely limit the performance of gallium nitride high-electron-mobility transistors (GaN HEMTs) in high-power radio frequency (RF) applications. Diamond capping technology leveraging diamond’s exceptional thermal conductivity (>2000 W/m·K) has emerged as a highly promising near-junction cooling solution. However, its integration with GaN HEMTs faces challenges including lattice/thermal mismatch, high thermal boundary resistance (TBR), and process compatibility. This review summarizes recent progress in high-thermal-conductivity diamond film growth, TBR optimization, thermal simulations, and the integrated process with GaN devices. These technological breakthroughs enable diamond-capped GaN HEMTs with an excellent comprehensive performance. Continued advances in these fields will be critical for fully releasing the capabilities of diamond capping technology for GaN HEMTs in high-frequency and high-power applications. Full article

(This article belongs to the Special Issue Electro-Thermal Transport in Nanometer-Scale Semiconductor Devices)

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