• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.2
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• pp.165-170
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• 2015

In this paper, we present design and measurement of LNA(Low Noise Amplifier) based on GaN HEMT(Gallium Nitride High Electron Mobility Transistor) to reduce the total noise figure of radar receiver and for robustness of LNA. In radar receiver using LNA based on GaAs(Gallium Arsenide) technology, limiter is necessary at the very front of the radar receiver to protect LNA. As a result, total noise figure of radar receiver is deteriorated. In this research, measured noise figure of LNA based on GaN HEMT is below 2 dB. In the case of commercialized GaAs LNA, recommended maximum input power is about 30 dBm. On the other hand, GaN HEMT LNA which is designed and measured is burned-out when input power is 43 dBm and robustness is guaranteed at input power 45.4 dBm.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.313-319
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• 2022

AlGaN/GaN based HfO₂ MOSHEMT (metal oxide semiconductor high electron transistor) with different gate recess depth was simulate to demonstrate a successful normally-off operation of the transistor. Three types of the HEMT structures including a conventional HEMT, a gate-recessed HEMT with 3 nm thick AlGaN layer, and MIS-HEMT without AlGaN layer in the gate region. The conventional HEMT showed a normally-on characteristics with a drain current of 0.35 A at V_G = 0 V and V_DS = 15 V. The recessed HEMT with 3 nm AlGaN layer exhibited a decreased drain current of 0.15 A under the same bias condition due to the decrease of electron concentration in 2DEG (2-dimensional electron gas) channel. For the last HEMT structure, distinctive normally- off behavior of the transistor was observed, and the turn-on voltage was shifted to 0 V.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.292-293
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• 2020

본 논문은 차세대 전력반도체 GaN HEMT (High Electron Mobility Transistor)를 적용한 통신전원 시스템용 LLC 컨버터의 설계에 대해 다룬다. GaN HEMT 소자의 노이즈를 저감하기 위해 3-level 게이트 드라이버를 설계하였다. 설계한 게이트 드라이버와 GaN HEMT를 적용한 3kW급 LLC 공진 네트워크를 설계하였고, 테스트 베드를 제작하여 실험을 통해 시스템의 성능을 검증하였다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.12
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• pp.103-112
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• 2005

In this paper, in order to derive the current-voltage characteristics of n-AlGaN/GaN HEMTs with the piezoelectric and spontaneous polarizations, we suggested analytical solutions for the two-dimensional Poisson equation in the AlGaN and GaN regions by taking into account the longitudinal field variation, field-dependent mobility, and the continuity condition of the channel current flowing in the quantum well. Obtained expressions for long and short channel devices would be applicable to the entire operating regions in a unified manner. Simulation results show that the drain saturation current increases and the cutoff voltage decreases as drain voltage increases. Compared with the conventional models, the present model seems to provide more reasonable explanation for the drain-induced threshold voltage roll-off and the channel length modulation effect.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.6
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• pp.451-458
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• 2020

In this study, a trade-off analysis of a power conversion system (PCS) is performed in accordance with a power semiconductor device to establish the suitable operating frequency range for the anyplace induction heating system. A resonant network is designed under each operating frequency condition to compare and analyze the PCS losses depending on the power semiconductor device. On the basis of the simulation results, the PCS losses and frequency condition are calculated. The calculated results are then used for a trade-off analysis between Si-MOSFET and GaN-HEMT based on PCS. The suitable operating frequency range is determined, and the validity of the analysis results is verified by the experiment results.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.294-295
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• 2020

차세대 전력반도체 중 하나인 GaN HEMT(Gallium Nitride High Electron Mobility Transistor)는 낮은 온 저항, 고속 스위칭 및 낮은 출력 커패시턴스 특성을 가지므로 더 높은 전력밀도를 달성할 수 있다. 그러나 낮은 문턱 전압 및 높은 dv/dt로 인해 외부 요인에 취약하다. 본 논문에서는 GaN HEMT를 3kW급 단상 인버터에 적용 시 발생한 문제점을 분석하고 해결방안을 제시한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.621-627
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• 2011

In this paper, we analysed performance for on-wafer GaN HEMT using load-pull in X-band, and studied optimum impedance point based on analysis result. We suggested method of optimum performance device by analysis of optimum impedance for solid state device on-wafer condition before packaging. The measured device is gate length 0.25um, and gate width is 400um, 800um. device 400um is performed $P_{sat}$=33.16dBm, PAE=67.36%, Gain=15.16dBm, and device 800um is performed $P_{sat}$=35.91dBm, PAE=69.23%, Gain=14.87dBm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.5
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• pp.430-433
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• 2017

This paper presents a S/C/X-band LNA MMIC with resistive feedback structure in 0.25 um GaN HEMT process. The GaN devices have advantages as a high output power device having high breakdown voltage, energy band gap and stability at high temperature. Since the receiver using the GaN device with high linearity can be implemented without a limiter, the noise figure of the receiver can be improved and the size of receiver module can be reduced. The proposed GaN LNA MMIC based on 0.25 um GaN HEMT device is achieved the gain of > 15 dB, the noise figure of < 3 dB, the input return loss of > 13 dB, and the output return loss of > 8 dB in the S/C/X-band. The current consumption of GaN LNA MMIC is 70 mA with the drain voltage 20 V and the gate voltage -3 V.

• Journal of Power Electronics
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• v.17 no.3
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• pp.601-609
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• 2017

Gallium nitride (GaN) power switching devices are promising candidates for high switching frequency and high efficiency power conversion due to their fast switching, low on-state resistance, and high-temperature operation capability. In order to facilitate the use of these new devices better, it is required to investigate the device characteristics and performance in detail preferably by comparing with various conventional silicon (Si) devices. This paper presents a comprehensive study of GaN high electron mobility transistor (HEMT) based non-isolated point-of-load (POL) synchronous buck converter operating at 2.7 MHz with a high step-down ratio (24 V to 3.3 V). The characteristics and performance of GaN HEMT and three different Si devices are analytically investigated and the optimal operating point for GaN HEMT is discussed. Zero-voltage switching (ZVS) is implemented to minimize switching loss in high switching frequency operation. The prototype circuit and experimental data support the validity of analytical and simulation results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.7
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• pp.705-711
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• 2003

In this Paper, 2${\times}$100 $\mu\textrm{m}$ AlCaN/GaN HEMT's(on sapphire substrate) large signal model including thermal effect was extracted. An equation based empirical model was employed to make large signal model for convergence and high speed. Pulsed I-V measurement was performed to extract thermal resistance and capacitance. Power amplifiers with 9 mm and 15 mm AlCaN/GaN HEMTS were designed using scaled modeling results of 2${\times}$100 $\mu\textrm{m}$ device respectively. From comparisons between measured and simulated data, the model considering of thermal effects gave better agreement than without one. It demonstrates that thermal modeling must be performed for power amplifier that uses large size transistors.