• 한국표면공학회지
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• 제36권2호
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• pp.135-140
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• 2003

The difference in lattice parameter and thermal expansion coefficient between GaN and Si which results in many defects into the grown GaN is larger than that between GaN and sapphire. In order to obtain high quality GaN films on Si substrate, it is essential to understand growth characteristics of GaN. In this study, GaN layers were grown on Si(111) substrates by MOCVD at three different GaN growth temperatures ($900^{\circ}C$, $1,000^{\circ}C$ and $1,100^{\circ}C$), using AlN and LT-GaN buffer layers. Using TEM, we carried out the comparative investigation of growth characteristics of GaN by characterizing lattice coherency, crystallinity, orientation relationship and defects formed (transition region, stacking fault, dislocation, etc). The localized region with high defect density was formed due to the lattice mismatch between AlN buffer layer and GaN. As the growth temperature of GaN increases, the defect density and surface roughness of GaN are decreased. In the case of GaN grown at $1,100^{\circ}$, growth thickness is decreased, and columns with out-plane misorientation are formed.

• Nuclear Engineering and Technology
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• 제52권7호
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• pp.1537-1544
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• 2020

Molecular dynamics (MD) simulations were conducted to investigate the temperature effects on the primary damage in gallium nitride (GaN) material. Five temperatures ranging from 300 K to 900 K were studied for 10 keV Ga primary knock-on atom (PKA) with inject direction of [0001]. The results of MD simulations showed that threshold displacement energy (E_d) was affected by temperatures and at higher temperature, it was larger. The evolutions of defects under various temperatures were similar. However, the higher temperature was found to increase the peak number, peak time, final time and recombination efficiency while decreasing the final number. With regard to clusters, isolated point defects and little clusters were common clusters and the fraction of point defects increased with temperature for vacancy clusters, whereas it did not appear in the interstitial clusters. Finally, at each temperature, the number of Ga interstitial atoms was larger than that of N and besides that, there were other different results of specific types of split interstitial atoms.

• 전자통신동향분석
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• 제34권5호
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• pp.71-80
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• 2019

Gallium nitride (GaN) can be used in high-voltage, high-power-density/-power, and high-speed devices owing to its characteristics of wide bandgap, high carrier concentration, and high electron mobility/saturation velocity. In this study, we investigate the technology trends for X-/Ku-band GaN RF power devices and MMIC power amplifiers, focusing on gate-length scaling, channel structure, and power density for GaN RF power devices and output power level and output power density for GaN MMIC power amplifiers. Additionally, we review the technology trends in gallium arsenide (GaAs) RF power devices and MMIC power amplifiers and analyze the technology trends in RF power devices and MMIC power amplifiers based on both GaAs and GaN. Furthermore, we discuss the current direction of national research by examining the national and international technology trends with respect to X-/Ku-band power devices and MMIC power amplifiers.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 추계학술대회 논문집
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• pp.197-198
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• 2014

본 논문에서는 Si MOSFET을 차세대 반도체인 GaN FET(Gallium Nitride Field Effect Transistor)으로의 대체 할 시 발생하는 문제점을 분석한다. 다양한 전력변환 시스템에 적용 가능한 위상 천이 풀브리지(Phase Shifted Full Bridge) DC-DC 컨버터를 대상으로 각각 Si MOSFET 및 GaN FET를 적용하고 실험을 통해 문제점을 확인 및 분석한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.324-325
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• 2018

본 논문에서는 GaN(Gallium Nitride) HEMT를 적용한 300W급 자기유도 방식 무선전력전송 시스템을 설계 및 구현한다. GaN HEMT의 물성적 특성을 고려하여 무선전력전송 시스템을 설계하며 이를 검증하기 위해 300W급 Prototype 무선전력전송 시스템을 구현하고 Simulation과 실험을 통해 논문에서 제시한 설계과정의 타당성을 검증한다.

• Journal of Semiconductor Engineering
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• 제2권1호
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• pp.119-124
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• 2021

Along with the needs for feasibility in the field of space applications, interests in radiation-hardened electronics is growing rapidly. Gallium nitride (GaN)-based devices have been widely researched so far owing to superb radiation resistance. Among them, research on the most abundant protons in low earth orbit (LEO) is essential. In this paper, proton irradiation effects on parameter changes, degradation mechanism, and correlation with reliability of GaN-based devices are summarized.

• 한국진공학회지
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• 제20권4호
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• pp.271-275
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• 2011

본 논문은 고휘도 발광소자의 특성을 높이기 위한 p-GaN 박의 홀농도 향상을 연구하였다. 우리는 metal organic chemical vapor deposition 법을 이용하여 Antimony (Sb)가 p-GaN의 홀농도 향상에 도움을 주는 것을 확인하였다. Atomic force microscope 측정을 통해 Sb가 계면활성제처럼 역할을 함으로써 p-GaN의 2차원 성장이 촉진됨을 알 수 있었다. 또한 X-ray diffraction 결과 [002] 면과 [102] 면의 반폭치가 Sb 도핑과 함께 줄어드는 것을 통해 Edge과 Screw 전위의 감소와 photoluminescence 결과에서 450~500 nm 청색 파장 영역에서 발광의 세기가 현저히 줄어드는 것으로 보아 질소 공극이 감소되는 것이 홀농도 향상의 주된 원임임을 알 수 있었다. Trimethylantimony가 10 ${\mu}mol/min$일 때 홀농도는 최대가 되었고 그때 홀농도는 $5.4{\times}10^{17}cm^{-3}$이었다.

• 한국재료학회지
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• 제15권5호
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• pp.348-352
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• 2005

Gallium oxyhydroxide (GaOOH) powders were heat-treated in a flowing ammonia gas to form GaN, and the reaction kinetics of the oxide to nitride was quantitatively determined by X-ray diffraction analysis. GaOOH turned into intermediate mixed phases of $\alpha-\;and\;\beta-Ga_2O_3$, and then single phase of GaN. The reaction time for full conversion $(t_c)$ decreased as the temperature increased. There were two-types of rapid reaction processes with the reaction temperature in the initial stage of nitridation at below $t_c$, and a relatively slow processes followed over $t_c$ does not depends on temperatures. The nitridation process was found to be limited by the rate of an interfacial reaction with the reaction order n value of 1 at $800^{\circ}C$ and by the diffusion-limited reaction with the n of 2 at above $1000^{\circ}C$, respectively, at below $t_c$. The activation energy for the reaction was calculated to be 1.84 eV in the temperature of below $830^{\circ}C$, and decreased to 0.38 eV above $830^{\circ}C$. From the comparative analysis of data, it strongly suggest the rate-controlling step changed from chemical reaction to mass transport above $830^{\circ}C$.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 1998년도 춘계학술발표회 초록집
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• pp.162-163
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• 1998

• 공업화학
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• 제25권4호
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• pp.414-417
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• 2014

습식제련 기술을 통한 Ga의 재활용을 위해 고결정성 GaN으로 구성되어 있는 LED 공정스크랩의 침출 거동을 연구하였다. 고결정성 GaN은 산성 및 염기성 조건에서 매우 안정하여 침출이 어려운 물질로 알려져 있다. 따라서, 본 연구에서는 볼밀링을 통해 원료와 $Na_2CO_3$를 1:1 비율로 섞은 후 관상로를 이용해 $1000-1200^{\circ}C$에서 열처리 하여 산화물로의 상변화를 유도하였다. 열처리 결과로써, $1100^{\circ}C$에서 GaN은 약 73 wt%의 Ga을 포함하는 산화물로 상변화 되었다. 이러한 열처리 샘플은 $100^{\circ}C$ 4 M HCl에서 96%의 높은 침출률을 나타냈다.