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9 pages, 3790 KiB

Open AccessArticle

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 - 9 May 2022

Cited by 2 | Viewed by 2000

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

Open AccessArticle

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 9 | Viewed by 3691

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

Open AccessArticle

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 7 | Viewed by 3529

Abstract

This paper proposes a novel p-GaN HEMT (P-HEMT) by clamping channel potential to improve breakdown voltage (BV) and threshold voltage (V_TH) 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 (V_TH) 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 V_TH stability. Compared with the conventional p-GaN HEMT (C-HEMT), simulation results show that the BV is improved by 120%, and the V_TH 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 V_TH 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

Open AccessArticle

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 6 | Viewed by 3077

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 (C_GA (C_GC)), the proposed diode could be triggered by a required voltage and possesses a high secondary breakdown current (I_S) in both forward and reverse transient ESD events. Based on the experimental verification, it was found that the bidirectional triggering voltages (V_trig) and I_S of the proposed diode were strongly related to C_GA (C_GC). With C_GA (C_GC) increasing from 5 pF to 25 pF, V_trig and I_S 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

Open AccessArticle

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 - 4 Jan 2022

Cited by 18 | Viewed by 5016

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

Open AccessArticle

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 6 | Viewed by 3740

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

Open AccessArticle

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 5 | Viewed by 2754

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

Open AccessArticle

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 2433

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

Open AccessArticle

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 4 | Viewed by 2644

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

Open AccessArticle

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 5 | Viewed by 2818

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

Open AccessArticle

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 3 | Viewed by 3165

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

Open AccessArticle

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 9 | Viewed by 3231

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 V_GS = 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

Open AccessArticle

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 2395

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

Open AccessArticle

Understanding the Leakage Mechanisms and Breakdown Limits of Vertical GaN-on-Si p⁺n⁻n 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 3977

Abstract

This work investigates p⁺n⁻n 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⁺n⁻n 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

Open AccessArticle

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 3273

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

Open AccessArticle

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 2801

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 (NF_min) 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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