GaN-Based Semiconductor Devices

A special issue of Micromachines (ISSN 2072-666X). This special issue belongs to the section "D1: Semiconductor Devices".

Deadline for manuscript submissions: closed (10 October 2021) | Viewed by 42812

Special Issue Editors

Centre for Microsystems Technology, IMEC & Ghent University, Technologiepark 126, B-9052 Ghent, Belgium
Interests: GaN; power devices; semiconductor device physics; device modeling; technology computer-aided design (TCAD)
Department of Information Engineering, University of Padova, Via Gradenigo 6/B, I-35131 Padova, Italy
Interests: characterization; reliability; compound semiconductor devices; LEDs; laser diodes; HEMTs; solar cells
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Semiconductor devices based on GaN for power or radio frequency (RF) applications have been on the market for several years. Devices with extraordinary figures of merit can be produced by exploiting the intriguing properties of GaN and related compound semiconductors (AlN, AlGaN). High-voltage ratings in the OFF-state can be combined with low specific ON-resistance, fast switching speeds, and high-temperature operation. Yet the full potential of GaN-based devices is to be unleashed. The challenges are firstly in the material quality, especially for devices made on silicon substrates by epitaxial growth techniques. Secondly, stable and robust passivation schemes have to be further optimized and better understood to deal with instability and reliability issues. Thirdly, the packaging of these devices is becoming ever more important to deal with thermal aspects. GaN technology is evolving rapidly with the introduction of new substrate materials, modern dielectric passivation stacks, and emerging device concepts. This Special Issue will publish research papers and review articles that focus on recent advancements in GaN technology and devices, insights into the physics of GaN, related compound materials, and passivation dielectrics, as well as application-oriented research.

Prof. Dr. Benoit Bakeroot
Prof. Dr. Matteo Meneghini
Guest Editors

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Keywords

  • GaN
  • power devices
  • RF
  • reliability
  • modeling
  • GaN technology

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Published Papers (16 papers)

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Research

9 pages, 3790 KiB  
Article
Investigation on Capacitance Collapse Induced by Secondary Capture of Acceptor Traps in AlGaN/GaN Lateral Schottky Barrier Diode
by Haitao Zhang, Xuanwu Kang, Yingkui Zheng, Ke Wei, Hao Wu, Xinyu Liu, Tianchun Ye and Zhi Jin
Micromachines 2022, 13(5), 748; https://doi.org/10.3390/mi13050748 - 09 May 2022
Cited by 2 | Viewed by 1590
Abstract
In this study, a dedicated dynamic measurement system was used to investigate the transient capacitance and recovery process of AlGaN/GaN lateral Schottky barrier diodes (SBDs). With the consideration of acceptor traps in the C-doped buffer, the C-V characteristics and transient capacitance were measured [...] Read more.
In this study, a dedicated dynamic measurement system was used to investigate the transient capacitance and recovery process of AlGaN/GaN lateral Schottky barrier diodes (SBDs). With the consideration of acceptor traps in the C-doped buffer, the C-V characteristics and transient capacitance were measured and analyzed, and the results were simulated and explained by Silvaco TCAD (technology computer aided design). The ionization of acceptor traps and the change of electric potential were monitored in transient simulation to investigate the origin of the capacitance collapse in the SBD. The results suggest the significant impact of traps in the GaN buffer layer on the capacitance collapse of the device, and the secondary capture effect on the variation of acceptor ionization. Based on the study of transient capacitance of SBD, this work could be extended to the Miller capacitance in high electron mobility transistor (HEMT) devices. Moreover, the report on the stability of capacitance is essential for GaN devices, and could be further extended to other aspects of device research. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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9 pages, 8784 KiB  
Article
Wideband Doherty Power Amplifier: A Design Approach
by Jorge Julián Moreno Rubio, Edison Ferney Angarita Malaver and Luis Ángel Lara González
Micromachines 2022, 13(4), 497; https://doi.org/10.3390/mi13040497 - 23 Mar 2022
Cited by 6 | Viewed by 2983
Abstract
This paper presents a simple method to design wideband Doherty power amplifiers (DPAs) based on the synthesis of a combiner network which can mimic the response of an ideal compensation of the device reactive output equivalent network and exploit the maximum power capabilities [...] Read more.
This paper presents a simple method to design wideband Doherty power amplifiers (DPAs) based on the synthesis of a combiner network which can mimic the response of an ideal compensation of the device reactive output equivalent network and exploit the maximum power capabilities of the device. Using the Wolfspeed’s CGH40006 and CG2H40025 GaN HEMT devices, two DPAs were designed and simulated to demonstrate the effectiveness of the proposed approach. In both cases, a 1.4 GHz bandwidth was obtained together with an efficiency higher than 44 and 49% at 6 dB OBO. The saturated output power was higher than 41.2 and 47 dBm over the band, for the DPAs using the CGH40006 and CG2H40025 devices, respectively. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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10 pages, 3840 KiB  
Article
Improving Breakdown Voltage and Threshold Voltage Stability by Clamping Channel Potential for Short-Channel Power p-GaN HEMTs
by Hongyue Wang, Yijun Shi, Yajie Xin, Chang Liu, Guoguang Lu and Yun Huang
Micromachines 2022, 13(2), 176; https://doi.org/10.3390/mi13020176 - 25 Jan 2022
Cited by 5 | Viewed by 2891
Abstract
This paper proposes a novel p-GaN HEMT (P-HEMT) by clamping channel potential to improve breakdown voltage (BV) and threshold voltage (VTH) stability. The clamping channel potential for P-HEMT is achieved by a partially-recessed p-GaN layer (PR p-GaN layer). At high [...] Read more.
This paper proposes a novel p-GaN HEMT (P-HEMT) by clamping channel potential to improve breakdown voltage (BV) and threshold voltage (VTH) stability. The clamping channel potential for P-HEMT is achieved by a partially-recessed p-GaN layer (PR p-GaN layer). At high drain bias, the two-dimensional electron gas (2DEG) channel under the PR p-GaN layer is depleted to withstand the drain bias. Therefore, the channel potential at the drain-side of the p-GaN layer is clamped to improve BV and VTH stability. Compared with the conventional p-GaN HEMT (C-HEMT), simulation results show that the BV is improved by 120%, and the VTH stability induced by high drain bias is increased by 490% for the same on-resistance. In addition, the influence of the PR p-GaN layers’ length, thickness, doping density on BV and VTH stability is analyzed. The proposed device can be a good reference to improve breakdown voltage and threshold voltage stability for short-channel power p-GaN HEMTs. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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11 pages, 3976 KiB  
Article
A Novel Bidirectional AlGaN/GaN ESD Protection Diode
by Bin Yao, Yijun Shi, Hongyue Wang, Xinbin Xu, Yiqiang Chen, Zhiyuan He, Qingzhong Xiao, Lei Wang, Guoguang Lu, Hao Li, Yun Huang and Bo Zhang
Micromachines 2022, 13(1), 135; https://doi.org/10.3390/mi13010135 - 15 Jan 2022
Cited by 5 | Viewed by 2372
Abstract
Despite the superior working properties, GaN-based HEMTs and systems are still confronted with the threat of a transient ESD event, especially for the vulnerable gate structure of the p-GaN or MOS HEMTs. Therefore, there is still an urgent need for a bidirectional ESD [...] Read more.
Despite the superior working properties, GaN-based HEMTs and systems are still confronted with the threat of a transient ESD event, especially for the vulnerable gate structure of the p-GaN or MOS HEMTs. Therefore, there is still an urgent need for a bidirectional ESD protection diode to improve the ESD robustness of a GaN power system. In this study, an AlGaN/GaN ESD protection diode with bidirectional clamp capability was proposed and investigated. Through the combination of two floating gate electrodes and two pF-grade capacitors connected in parallel between anode or cathode electrodes and the adjacent floating gate electrodes (CGA (CGC)), the proposed diode could be triggered by a required voltage and possesses a high secondary breakdown current (IS) in both forward and reverse transient ESD events. Based on the experimental verification, it was found that the bidirectional triggering voltages (Vtrig) and IS of the proposed diode were strongly related to CGA (CGC). With CGA (CGC) increasing from 5 pF to 25 pF, Vtrig and IS decreased from ~18 V to ~7 V and from ~7 A to ~3 A, respectively. The diode’s high performance demonstrated a good reference for the ESD design of a GaN power system. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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10 pages, 3744 KiB  
Article
Comprehensive Schottky Barrier Height Behavior and Reliability Instability with Ni/Au and Pt/Ti/Pt/Au on AlGaN/GaN High-Electron-Mobility Transistors
by Surajit Chakraborty and Tae-Woo Kim
Micromachines 2022, 13(1), 84; https://doi.org/10.3390/mi13010084 - 04 Jan 2022
Cited by 14 | Viewed by 3704
Abstract
The reliability instability of inhomogeneous Schottky contact behaviors of Ni/Au and Pt/Ti/Pt/Au gate contacts on AlGaN/GaN high-electron-mobility transistors (HEMTs) was investigated via off-state stress and temperature. Under the off-state stress condition, Pt/Ti/Pt/Au HEMT showed abruptly reduced reverse leakage current, which improved the Schottky [...] Read more.
The reliability instability of inhomogeneous Schottky contact behaviors of Ni/Au and Pt/Ti/Pt/Au gate contacts on AlGaN/GaN high-electron-mobility transistors (HEMTs) was investigated via off-state stress and temperature. Under the off-state stress condition, Pt/Ti/Pt/Au HEMT showed abruptly reduced reverse leakage current, which improved the Schottky barrier height (SBH) from 0.46 to 0.69 eV by suppression of the interfacial donor state. As the temperature increased, the reverse leakage current of the Pt/Ti/Pt/Au AlGaN/GaN HEMT at 308 K showed more reduction under the same off-state stress condition while that of the Ni/Au AlGaN/GaN HEMT increased. However, with temperatures exceeding 308 K under the same off-state stress conditions, the reverse leakage current of the Pt/Ti/Pt/Au AlGaN/GaN HEMT increases, which can be intensified using the inverse piezoelectric effect. Based on this phenomenon, the present work reveals the necessity for analyzing the concurrent SBH and reliability instability due to the interfacial trap states of the MS contacts. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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8 pages, 2871 KiB  
Article
Low Subthreshold Slope AlGaN/GaN MOS-HEMT with Spike-Annealed HfO2 Gate Dielectric
by Min Jae Yeom, Jeong Yong Yang, Chan Ho Lee, Junseok Heo, Roy Byung Kyu Chung and Geonwook Yoo
Micromachines 2021, 12(12), 1441; https://doi.org/10.3390/mi12121441 - 25 Nov 2021
Cited by 5 | Viewed by 2975
Abstract
AlGaN/GaN metal-oxide semiconductor high electron mobility transistors (MOS-HEMTs) with undoped ferroelectric HfO2 have been investigated. Annealing is often a critical step for improving the quality of as-deposited amorphous gate oxides. Thermal treatment of HfO2 gate dielectric, however, is known to degrade [...] Read more.
AlGaN/GaN metal-oxide semiconductor high electron mobility transistors (MOS-HEMTs) with undoped ferroelectric HfO2 have been investigated. Annealing is often a critical step for improving the quality of as-deposited amorphous gate oxides. Thermal treatment of HfO2 gate dielectric, however, is known to degrade the oxide/nitride interface due to the formation of Ga-containing oxide. In this work, the undoped HfO2 gate dielectric was spike-annealed at 600 °C after the film was deposited by atomic layer deposition to improve the ferroelectricity without degrading the interface. As a result, the subthreshold slope of AlGaN/GaN MOS-HEMTs close to 60 mV/dec and on/off ratio>109 were achieved. These results suggest optimizing the HfO2/nitride interface can be a critical step towards a low-loss high-power switching device. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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11 pages, 3948 KiB  
Article
Investigation on Dynamic Characteristics of AlGaN/GaN Lateral Schottky Barrier Diode
by Haitao Zhang, Xuanwu Kang, Yingkui Zheng, Hao Wu, Ke Wei, Xinyu Liu, Tianchun Ye and Zhi Jin
Micromachines 2021, 12(11), 1296; https://doi.org/10.3390/mi12111296 - 22 Oct 2021
Cited by 4 | Viewed by 2155
Abstract
This work investigates the transient characteristics of an AlGaN/GaN lateral Schottky barrier diode (SBD) and its recovery process with a dedicated dynamic measurement system. Both static and dynamic characteristics were measured, analyzed with the consideration of acceptor/donor traps in the C-doped buffer and [...] Read more.
This work investigates the transient characteristics of an AlGaN/GaN lateral Schottky barrier diode (SBD) and its recovery process with a dedicated dynamic measurement system. Both static and dynamic characteristics were measured, analyzed with the consideration of acceptor/donor traps in the C-doped buffer and GaN channel, and verified by Silvaco TCAD (technology computer aided design) simulations. The energy band, electric field, and electron concentration were monitored in the transient simulation to study the origin of the current collapse in the SBD. Using the verified model, the impact of carbon doping concentration in the buffer and the thickness of the unintentionally doped (UID) GaN channel in the transient behavior was estimated. Several observations were revealed. Firstly, the traps in the GaN channel and buffer layer have a significant impact on the current collapse of the device. A severe deterioration of current collapse can be observed in the SBDs with increasing density of acceptor-like traps. Secondly, the current collapse increases with the thinner UID GaN channel layer. This well-performed simulation model shows promise to be utilized for the dynamic performance optimization of GaN lateral devices. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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11 pages, 5107 KiB  
Article
A Novel Step–Doped Channel AlGaN/GaN HEMTs with Improved Breakdown Performance
by Jianhua Liu, Yufeng Guo, Jun Zhang, Jiafei Yao, Man Li, Maolin Zhang, Jing Chen, Xiaoming Huang and Chenyang Huang
Micromachines 2021, 12(10), 1244; https://doi.org/10.3390/mi12101244 - 14 Oct 2021
Cited by 4 | Viewed by 1854
Abstract
The AlGaN/GaN high electron mobility transistor with a step–doped channel (SDC–HEMT) is first proposed in this paper. The potential distribution and the electric field (E–field) distribution of the device are explored by the numerical approach and analytical approach simultaneously. By introducing extra dopants [...] Read more.
The AlGaN/GaN high electron mobility transistor with a step–doped channel (SDC–HEMT) is first proposed in this paper. The potential distribution and the electric field (E–field) distribution of the device are explored by the numerical approach and analytical approach simultaneously. By introducing extra dopants to the channel layer, the E–field distribution along the AlGaN/GaN heterojunction interface is reshaped, resulting in an improved breakdown characteristic. An optimized doping concentration gradient of channel layer of 2 × 1016 cm−3/step is proposed and verified by simulations. The breakdown voltage (BV) of the optimized SDC–HEMT reaches 1486 V with a 59.8% improvement compared with conventional AlGaN/GaN HEMT. In addition, the average E–field in the region between gate and drain improves from 1.5 to 2.5 MV/cm. Based on the equivalent potential method (EPM), an analytical model of the E–field and potential distribution is presented. The veracity and effectiveness of the proposed methodology is verified by the good agreement between the simulated and modeled results. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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14 pages, 6504 KiB  
Article
Study of p-SiC/n-GaN Hetero-Structural Double-Drift Region IMPATT Diode
by Yang Dai, Qingsong Ye, Jiangtao Dang, Zhaoyang Lu, Weiwei Zhang, Xiaoyi Lei, Yunyao Zhang, Han Zhang, Chenguang Liao, Yang Li and Wu Zhao
Micromachines 2021, 12(8), 919; https://doi.org/10.3390/mi12080919 - 31 Jul 2021
Cited by 3 | Viewed by 2175
Abstract
Nowadays, the immature p-GaN processes cannot meet the manufacturing requirements of GaN impact ionization avalanche transit time (IMPATT) diodes. Against this backdrop, the performance of wide-bandgap p-SiC/n-GaN heterojunction double-drift region (DDR) IMPATT diode is investigated in this paper for the first time. The [...] Read more.
Nowadays, the immature p-GaN processes cannot meet the manufacturing requirements of GaN impact ionization avalanche transit time (IMPATT) diodes. Against this backdrop, the performance of wide-bandgap p-SiC/n-GaN heterojunction double-drift region (DDR) IMPATT diode is investigated in this paper for the first time. The direct-current (DC) steady-state, small-signal and large-signal characteristics are numerically simulated. The results show that compared with the conventional GaN single-drift region (SDR) IMPATT diode, the performance of the p-SiC/n-GaN DDR IMPATT proposed in this design, such as breakdown voltage, negative conductance, voltage modulation factor, radio frequency (RF) power and DC-RF conversion efficiency have been significantly improved. At the same time, the structure proposed in this design has a larger frequency bandwidth. Due to its greater potential in the RF power density, which is 1.97 MW/cm2 in this study, indicates that the p-SiC/n-GaN heterojunction provides new possibilities for the design and manufacture of IMPATT diode. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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10 pages, 7018 KiB  
Article
Effects of Proton Irradiation on the Current Characteristics of SiN-Passivated AlGaN/GaN MIS-HEMTs Using a TMAH-Based Surface Pre-Treatment
by Young Jun Yoon, Jae Sang Lee, Jae Kwon Suk, In Man Kang, Jung Hee Lee, Eun Je Lee and Dong Seok Kim
Micromachines 2021, 12(8), 864; https://doi.org/10.3390/mi12080864 - 23 Jul 2021
Cited by 2 | Viewed by 2286
Abstract
This study investigated the combined effects of proton irradiation and surface pre-treatment on the current characteristics of Gallium Nitride (GaN)-based metal-insulator-semiconductor high-electron-mobility-transistors (MIS-HEMTs) to evaluate the radiation hardness involved with the Silicon Nitride (SiN) passivation/GaN cap interface. The impact of proton irradiation on [...] Read more.
This study investigated the combined effects of proton irradiation and surface pre-treatment on the current characteristics of Gallium Nitride (GaN)-based metal-insulator-semiconductor high-electron-mobility-transistors (MIS-HEMTs) to evaluate the radiation hardness involved with the Silicon Nitride (SiN) passivation/GaN cap interface. The impact of proton irradiation on the static and dynamic current characteristics of devices with and without pre-treatment were analyzed with 5 MeV proton irradiation. In terms of transfer characteristics before and after the proton irradiation, the drain current of the devices without and with pre-treatment were reduced by an increase in sheet and contact resistances after the proton irradiation. In contrast with the static current characteristics, the gate-lag characteristics of the device with pre-treatment were significantly degenerated. In the device with pre-treatment, the hydrogen passivation for surface states of the GaN cap was formed by the pre-treatment and SiN deposition processes. Since the hydrogen passivation was removed by the proton irradiation, the newly created vacancies resulted in the degeneration of gate-lag characteristics. After nine months in an ambient atmosphere, the gate-lag characteristics of the device with pre-treatment were recovered because of the hydrogen recombination. These results demonstrated that the radiation hardness of MIS-HEMTs was affected by the SiN/GaN interface quality. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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11 pages, 8021 KiB  
Article
Double-Quantum-Well AlGaN/GaN Field Effect Transistors with Top and Back Gates: Electrical and Noise Characteristics
by Maksym Dub, Pavlo Sai, Maciej Sakowicz, Lukasz Janicki, Dmytro B. But, Paweł Prystawko, Grzegorz Cywiński, Wojciech Knap and Sergey Rumyantsev
Micromachines 2021, 12(6), 721; https://doi.org/10.3390/mi12060721 - 19 Jun 2021
Cited by 1 | Viewed by 2586
Abstract
AlGaN/GaN fin-shaped and large-area grating gate transistors with two layers of two-dimensional electron gas and a back gate were fabricated and studied experimentally. The back gate allowed reducing the subthreshold leakage current, improving the subthreshold slope and adjusting the threshold voltage. At a [...] Read more.
AlGaN/GaN fin-shaped and large-area grating gate transistors with two layers of two-dimensional electron gas and a back gate were fabricated and studied experimentally. The back gate allowed reducing the subthreshold leakage current, improving the subthreshold slope and adjusting the threshold voltage. At a certain back gate voltage, transistors operated as normally-off devices. Grating gate transistors with a high gate area demonstrated little subthreshold leakage current, which could be further reduced by the back gate. The low frequency noise measurements indicated identical noise properties and the same trap density responsible for noise when the transistors were controlled by either top or back gates. This result was explained by the tunneling of electrons to the traps in AlGaN as the main noise mechanism. The trap density extracted from the noise measurements was similar or less than that reported in the majority of publications on regular AlGaN/GaN transistors. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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8 pages, 3401 KiB  
Article
Response Enhancement of Pt–AlGaN/GaN HEMT Gas Sensors by Thin AlGaN Barrier with the Source-Connected Gate Configuration at High Temperature
by Tuan-Anh Vuong, Ho-Young Cha and Hyungtak Kim
Micromachines 2021, 12(5), 537; https://doi.org/10.3390/mi12050537 - 10 May 2021
Cited by 7 | Viewed by 2735
Abstract
AlGaN/GaN HEMT hydrogen gas sensors were optimized by AlGaN barrier thickness in the gate-source connected configuration demonstrated high response and robust stability up to 500 °C. First, we found that the hydrogen sensing performance of a conventional normally-on HEMT-based sensor was enhanced when [...] Read more.
AlGaN/GaN HEMT hydrogen gas sensors were optimized by AlGaN barrier thickness in the gate-source connected configuration demonstrated high response and robust stability up to 500 °C. First, we found that the hydrogen sensing performance of a conventional normally-on HEMT-based sensor was enhanced when zero voltage was applied on the gate in comparison with a floating-gate condition due to a reduced level of the base current. In the next step, to take advantage of the response increase by VGS = 0 V, a new type of sensor with a source-connected gate (SCG) was fabricated to utilize the normally-on operation of the GaN HEMT sensor as a two-terminal device. AlGaN barrier thickness was thinned by the dry-etching process to gain higher transconductance at a zero-gate bias with the reduction of the distance from the 2DEG channel to the AlGaN surface, thereby significantly improve the hydrogen response. The SCG GaN sensor with an ultra-thin AlGaN barrier (9 nm) exhibited responses of 85% and 20% at 200 and 500 °C, respectively, onto 4%-hydrogen gas, which demonstrates a promising ability for harsh environment applications. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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26 pages, 17295 KiB  
Article
Investigation on GaN HEMTs Based Three-Phase STATCOM with Hybrid Control Scheme
by Chao-Tsung Ma and Zhen-Huang Gu
Micromachines 2021, 12(4), 464; https://doi.org/10.3390/mi12040464 - 20 Apr 2021
Viewed by 1968
Abstract
The modern trend of decarbonization has encouraged intensive research on renewable energy (RE)-based distributed power generation (DG) and smart grid, where advanced electronic power interfaces are necessary for connecting the generator with power grids and various electrical systems. On the other hand, modern [...] Read more.
The modern trend of decarbonization has encouraged intensive research on renewable energy (RE)-based distributed power generation (DG) and smart grid, where advanced electronic power interfaces are necessary for connecting the generator with power grids and various electrical systems. On the other hand, modern technologies such as Industry 4.0 and electrical vehicles (EV) have higher requirements for power converters than that of conventional applications. Consequently, the enhancement of power interfaces will play an important role in the future power generation and distribution systems as well as various industrial applications. It has been discovered that wide-bandgap (WBG) switching devices such as gallium nitride (GaN) high electron mobility transistors (HEMTs) and silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) offer considerable potential for outperforming conventional silicon (Si) switching devices in terms of breakdown voltage, high temperature capability, switching speed, and conduction losses. This paper investigates the performance of a 2kVA three-phase static synchronous compensator (STATCOM) based on a GaN HEMTs-based voltage-source inverter (VSI) and a neural network-based hybrid control scheme. The proportional-integral (PI) controllers along with a radial basis function neural network (RBFNN) controller for fast reactive power control are designed in synchronous reference frame (SRF). Both simulation and hardware implementation are conducted. Results confirm that the proposed RBFNN assisted hybrid control scheme yields excellent dynamic performance in terms of various reactive power tracking control of the GaN HEMTs-based three-phase STATCOM system. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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11 pages, 4609 KiB  
Article
Understanding the Leakage Mechanisms and Breakdown Limits of Vertical GaN-on-Si p+nn Diodes: The Road to Reliable Vertical MOSFETs
by Kalparupa Mukherjee, Carlo De Santi, Matteo Buffolo, Matteo Borga, Shuzhen You, Karen Geens, Benoit Bakeroot, Stefaan Decoutere, Andrea Gerosa, Gaudenzio Meneghesso, Enrico Zanoni and Matteo Meneghini
Micromachines 2021, 12(4), 445; https://doi.org/10.3390/mi12040445 - 16 Apr 2021
Cited by 12 | Viewed by 3228
Abstract
This work investigates p+nn GaN-on-Si vertical structures, through dedicated measurements and TCAD simulations, with the ultimate goal of identifying possible strategies for leakage and breakdown optimization. First, the dominant leakage processes were identified through temperature-dependent current–voltage characterization. Second, the [...] Read more.
This work investigates p+nn GaN-on-Si vertical structures, through dedicated measurements and TCAD simulations, with the ultimate goal of identifying possible strategies for leakage and breakdown optimization. First, the dominant leakage processes were identified through temperature-dependent current–voltage characterization. Second, the breakdown voltage of the diodes was modelled through TCAD simulations based on the incomplete ionization of Mg in the p+ GaN layer. Finally, the developed simulation model was utilized to estimate the impact of varying the p-doping concentration on the design of breakdown voltage; while high p-doped structures are limited by the critical electric field at the interface, low p-doping designs need to contend with possible depletion of the entire p-GaN region and the consequent punch-through. A trade-off on the value of p-doping therefore exists to optimize the breakdown. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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9 pages, 2809 KiB  
Article
Surface-Potential-Based Compact Modeling of p-GaN Gate HEMTs
by Jie Wang, Zhanfei Chen, Shuzhen You, Benoit Bakeroot, Jun Liu and Stefaan Decoutere
Micromachines 2021, 12(2), 199; https://doi.org/10.3390/mi12020199 - 15 Feb 2021
Viewed by 2689
Abstract
We propose a surface potential (SP)-based compact model of p-GaN gate high electron mobility transistors (HEMTs) which solves the Poisson equation. The model includes all possible charges in the GaN channel layer, including the unintended Mg doping density caused by out-diffusion. The SP [...] Read more.
We propose a surface potential (SP)-based compact model of p-GaN gate high electron mobility transistors (HEMTs) which solves the Poisson equation. The model includes all possible charges in the GaN channel layer, including the unintended Mg doping density caused by out-diffusion. The SP equation and its analytical approximate solution provide a high degree of accuracy for the SP calculation, from which the closed-form I–V equations are derived. The proposed model uses physical parameters only and is implemented in Verilog-A code. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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7 pages, 2170 KiB  
Article
Large-Signal Linearity and High-Frequency Noise of Passivated AlGaN/GaN High-Electron Mobility Transistors
by Yu-Shyan Lin and Shin-Fu Lin
Micromachines 2021, 12(1), 7; https://doi.org/10.3390/mi12010007 - 24 Dec 2020
Cited by 6 | Viewed by 2319
Abstract
This study proposes AlGaN/GaN/silicon high-electron mobility transistors (HEMTs) grown by a metallorganic chemical vapor deposition (MOCVD) system. The large-signal linearity and high-frequency noise of HEMTs without and with different passivation layers are compared. The experimental data show that the addition of a TiO [...] Read more.
This study proposes AlGaN/GaN/silicon high-electron mobility transistors (HEMTs) grown by a metallorganic chemical vapor deposition (MOCVD) system. The large-signal linearity and high-frequency noise of HEMTs without and with different passivation layers are compared. The experimental data show that the addition of a TiO2 passivation layer to undoped AlGaN/GaN HEMT’s increases the value of the third-order intercept point (OIP3) by up to 70% at 2.4 GHz. Furthermore, the minimum noise figure (NFmin) of the HEMT with TiO2 passivation is significantly reduced. Full article
(This article belongs to the Special Issue GaN-Based Semiconductor Devices)
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