• Title/Summary/Keyword: AlN layer

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The Properties of GaN Grown by BVPE Method on the Si(111) Substrate with Pre-deposited Al Layer (Al 박막이 증착 된 Si(111) 기판 위에 HVPE 방법으로 성장한 GaN의 특성)

  • Shin Dae Hyun;Baek Shin Young;Lee Chang Min;Yi Sam Nyung;Kang Nam Lyong;Park Seoung Hwan
    • Journal of the Korean Vacuum Society
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    • v.14 no.4
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    • pp.201-206
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    • 2005
  • In this work, we tried to improve the fabrication process in HVPE (Hydride Vapor Phase Epitaxy) system by using Si(111) substrate with pre-deposited Al layer. PL measurements was done for samples with and without pre-deposited Al on Si and it was also examined the dependence of the optical characteristic properties on AlN buffer thickness for GaN/AIN/Al/Si. A sample with thin Al nucleation layer on Si substrate reveals a better optical property than the other. And it suggests that the thickness for AlN buffer layer with thin Al nucleation layer on Si(111) substrate is most proper about $260{\AA}$ to grow GaN in HVPE system. The surface morphology of GaN clearly shows the hexagonal crystallization. The XRD pattern showed strong peak at GaN{0001} direction.

Evaluation of Thermal Conductivity for Screen-Printed AlN Layer on Al Substrate in Thickness Direction (알루미늄 기판에 스크린 인쇄한 AlN 후막의 두께 방향으로 열전도도 평가)

  • Kim, Jong-Gu;Park, Hong-Seok;Kim, Hyun;Hahn, Byung-Dong;Cho, Young-Rae
    • Journal of the Microelectronics and Packaging Society
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    • v.22 no.4
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    • pp.65-70
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    • 2015
  • A study on thermal properties for a single-layer metal and two-layer composites was investigated for the heat-sink application. For the single-layer metal, an aluminum alloy (Al6061) was selected. A screen printed aluminum nitride (AlN) layer on the Al6061 substrate was chosen for the two-layer composites. The thermal conductivity of the sample was determined from the thermal diffusivity measured by the light flash analysis (LFA), specific heat and density. Measured thermal property values were compared to calculated values using the data from the references. The thermal conductivity of composites with screen printed AlN layer on the Al6061 substrate decreased linearly with increasing the thickness of AlN layer. Measured values of the thermal conductivity for composites with $53{\mu}m$ and $163{\mu}m$ thick AlN layers were $114.1W/m{\cdot}K$ and $72.3W/m{\cdot}K$, respectively. In particular, the thermal conductivity of the screen-printed AlN layer was demonstrated by appling the rule of mixture in view point of thermal resistivity. Measured values of the thermal conductivity for AlN layers with the thickness of $53{\mu}m$ and $163{\mu}m$ showed $9.35W/m{\cdot}K$ and $12.40W/m{\cdot}K$, respectively.

Analysis of the Abnormal Voltage-Current Behaviors on Localized Carriers of InGaN/GaN Multiple Quantum well from Electron Blocking Layer

  • Nam, Giwoong;Kim, Byunggu;Park, Youngbin;Kim, Soaram;Kim, Jin Soo;Son, Jeong-Sik;Leem, Jae-Young
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.219-219
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    • 2013
  • The effect of an electron blocking layer (EBL) on V-I curves in GaN/InGaN multiple quantum well is investigated. For the first time, we found that curves were intersected at 3.012 V and analyzed the reason for intersection. The forward voltage in LEDs with an p-AlGaN EBL is larger than without p-AlGaN EBL at low injection current because the Mg doping efficiency for p-GaN layer was higher than that of p-AlGaN layer. However, the forward voltage in LEDs with an p-AlGaN EBL is smaller than without p-AlGaN EBL at high injection current because the carriers overflow from the active layer when injection current increases in LEDs without p-AlGaN EBL and in case of LED with p-AlGaN EBL, the carriers are blocked by EBL.

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The properties of AlGaN epi layer grown by HVPE (HVPE에 의해 성장된 AlGaN epi layer의 특성)

  • Jung, Se-Gyo;Jeon, Hun-Soo;Lee, Gang-Seok;Bae, Seon-Min;Yun, Wi-Il;Kim, Kyoung-Hwa;Yi, Sam-Nyung;Yang, Min;Ahn, Hyung-Soo;Kim, Suck-Whan;Yu, Young-Moon;Cheon, Seong-Hak;Ha, Hong-Ju
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.22 no.1
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    • pp.11-14
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    • 2012
  • The AlGaN layer has direct wide bandgaps ranging from 3.4 to 6.2 eV. Nowadays, it is becoming more important to fabricate optical devices in an UV region for the many applications. The high quality AlGaN layer is necessary to establish the UV optical devices. However, the growth of AlGaN layer on GaN layer is difficult due to the lattice mismatch and difference thermal expansion coefficient between GaN layer and AlGaN layer. In this paper, we attempted to grow the LED structure on GaN template by mixed-source HVPE method with multi-sliding boat system. We tried to find the optical and lattice transition of active layer by control the Al content in mixed-source. For the growth of epi layer, the HCl and $NH_3$ gas were flowed over the mixed-source and the carrier gas was $N_2$. The temperature of source zone and growth zone was stabled at 900 and $1090^{\circ}C$, respectively. After the growth, we performed the x-ray diffraction (XRD) and electro luminescence (EL) measurement.

A Study on the Properties of $Al_2$ $O_3$ and $Al_2$ $O_3$/( $Ti_{0.5}$ $Al_{0.5}$)N Coatings Produced by Plasma Enhanced Chemical Vapor Deposition (플라즈마 화학 증착법에 의한 $Al_2$ $O_3$ 단층피막과 $Al_2$ $O_3$/( $Ti_{0.5}$ $Al_{0.5}$)N 이중피막의 제조 및 특성에 관한 연구)

  • 손경석;이승훈;이동각;임주완;이후철;이정중
    • Journal of the Korean institute of surface engineering
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    • v.34 no.2
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    • pp.105-114
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    • 2001
  • $Al_2$$O_3$ coatings were deposited on M2 high speed steels by the plasma enhanced chemical vapor deposition (PECVD) process, using a gas mixture of AlC1$_3$, $H_2$, $CO_2$ and Ar $Al_2$$O_3$ coatings had interference color and showed amorphous phase. $A1_2$X$A1_3$/($Ti_{0.5}$ /$Al_{0.5}$ )N double layer coatings were produced in the sequence of substrate $NH_3$ plasma pretreatment, ($Ti_{0.5}$$Al_{0.5}$)N depoition process, $Al_2$$O_3$ deposition process. $Al_2$ $O_3$/( $Ti_{0.5}$A $l_{0.5}$)N double layer coatings showed NaCl structure in ( $Ti_{0.5}$A $l_{0.5}$)N layer and amorphous phase in A1$_2$ $O_3$ layer. It was shown that $Al_2$ $O_3$ columns continuously grew onto ( $Ti_{0.5}$A $l_{0.5}$)N columns. ( $Ti_{0.5}$A $l_{0.5}$)N single coating and $Al_2$ $O_3$/( $Ti_{0.5}$A $l_{0.5}$)N double layer coating were oxidized at $700^{\circ}C$, 80$0^{\circ}C$, 90$0^{\circ}C$ for 1hr, 3hr in atmosphere. At 80$0^{\circ}C$, single layer coatings were oxidized, which were examined substrate oxide particle. But $Al_2$ $O_3$/ ( $Ti_{0.5}$A $l_{0.5}$)N double layer coatings maintained the asdeposited state. Therefore, $Al_2$ $O_3$/ ( $Ti_{0.5}$A $l_{0.5}$)N double layer coatings have moreexcellent oxidation resistance than ( $Ti_{0.5}$A $l_{0.5}$)N single layer coatings.X> 0.5/)N single layer coatings.s.

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High Quality AlN Layer Regrown on AlN Nanostructure by Hydride Vapor Phase Epitaxy (나노구조를 응용한 AlN 성장 방법 및 특성)

  • Son, Hoki;Gim, Jinwon;Lim, Tea-Young;Lee, Mijai;Kim, Jin-Ho;Jeon, Dae-Woo;Hwang, Jonghee;Oh, Hae-Kon;Choi, YoungJun;Lee, Hae-Yong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.28 no.11
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    • pp.711-714
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    • 2015
  • In this paper, high quality AlN layers were regrown on AlN nanopillar structure with $SiO_2$-dots by HVPE. Surface morphology of AlN layer regrown exhibited flatter than a conventional AlN template. The laterally overgrown AlN regions would consist of a continuous well coalesced layer with lower dislocation density than in the template because of the dislocation blocking and dislocation bending effects. Moreover, result of Raman spectroscopy suggest that the AlN nanopillar structure with $SiO_2$-dots relieves the strain in the AlN layer regrown by HVPE.

Effect of metal buffer layers on the growth of GaN on Si substrates (실리콘 기판위에 금속 완충층을 이용한 GaN 성장과 특성분석)

  • Lee, Jun Hyeong;Yu, Yeon Su;Ahn, Hyung Soo;Yu, Young Moon;Yang, Min
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.23 no.4
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    • pp.161-166
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    • 2013
  • AlN buffer layers have been used for the growth of GaN layers on Si substrates. However, the doping of high concentration of carriers into AlN layers is still not easy, therefore it may cause the increase of series resistance when it is used for the electrical or optical devices. In this work, to improve such a problem, the growth of GaN layers on Si substrates were performed using metal buffer layers instead of AlN buffer layer. We tried combinations of Ti, Al, Cr and Au as metal buffer layers for the growth of GaN on Si substrates. Surface morphology was measured by optical microscope and scanning electron microscope (SEM), and optical properties and crystalline quality were measured by photoluminescence (PL) and X-ray diffractometer (XRD), respectively. Electrical resistances for both cases of AlN and metal buffer layer were compared by current-voltage (I-V) measurement.

Study on the Oxidation Resistance of Ti-Al-N Coating Layer (Ti-Al-N코팅층의 내산화 특성에 관한 연구)

  • 김충완;김광호
    • Journal of the Korean Ceramic Society
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    • v.34 no.5
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    • pp.512-518
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    • 1997
  • The high temperature oxidation behaviors of titanium nitride films prepared by PACVD technique were studied in the temperature range of from 50$0^{\circ}C$ to 80$0^{\circ}C$ under air atmosphere. Ti0.88Al0.12N film, which showed the excellent microhardness from the previous work, was investigated on its oxidation resistance compared with pure TiN film. Ti-Al-N film showed superior oxidation resistance up to $700^{\circ}C$, whereas TiN film was fast oxidized into rutile TiO2 crystallites from at 50$0^{\circ}C$. It was found that an amorphous layer having AlxTiyOz formula was formed on the surface region due to outward diffusion of Al ions at the initial stage of oxidation. The amorphous oxide layer played a role as a barrier against oxygen diffusion, protected the remained nitride layer from further oxidation, and thus, resulted in the high oxidation resistive characteristics of Ti-Al-N film.

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Sputtering of Multifunctional AlN Passivation Layer for Thermal Inkjet Printhead

  • Park, Min-Ho;Kim, Sang-Ho
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.50-50
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    • 2011
  • The aluminum nitride films were prepared by RF magnetron sputtering using an AlN ceramic target. The crystallinity, grain size, Al-N bonding and thermal conductivity were investigated in dependence on the plasma power densities (4.93, 7.40, 9.87 W/$cm^2$) during sputtering. High thermal conductivity is important properties of A1N passivation layer for functioning properly in thermal inkjet printhead. The crytallinity, grain size, Al-N bonding formation and chemical composition were observed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS), respectively. The AlN thin film was changed from amorphous to crystalline as the power density was increased, and the largest grain size appeared at medium power density. The near stoichiometry Al-N bonding ratio was acquired at medium power density. So, we know that the AlN thin film had better thermal conductivity with crystalline phase and near stoichometry Al-N bonding ratio at 7.40 W/$cm^2$ power density.

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Development of Selective GaN etching Process for p-GaN/AlGaN/GaN E-mode FET Fabrication (p-GaN/AlGaN/GaN E-mode FET 제작을 위한 선택적 GaN 식각 공정 개발)

  • Jang, Won-Ho;Cha, Ho-Young
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.24 no.2
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    • pp.321-324
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    • 2020
  • In this work, we developed a selective etching process for GaN that is a key process in p-GaN/AlGaN/GaN enhancement-mode (E-mode) power switching field-effect transistor (FET) fabrication. In order to achieve a high current density of p-GaN/AlGaN/GaN E-mode FET, the p-GaN layer beside the gate region must be selectively etched whereas the underneath AlGaN layer should be maintained. A selective etching process was implemented by oxidizing the surface of the AlGaN layer and the GaN layer by adding O2 gas to Cl2/N2 gas which is generally used for GaN etching. A selective etching process was optimized using Cl2/N2/O2 gas mixture and a high selectivity of 53:1 (= GaN/AlGaN) was achieved.