• 제목/요약/키워드: Aluminum nitride

검색결과 195건 처리시간 0.033초

나노 MgO-CaO-Al2O3-SiO2 glass 첨가제를 가진 AlN의 소결거동 및 열전도도 (Sintering Behavior and Thermal Conductivity of Aluminum Nitride Ceramics with MgO-CaO-Al2O3-SiO2 Nano-glass Additive)

  • 백수현;김경민;류성수
    • 한국분말재료학회지
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    • 제25권5호
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    • pp.426-434
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    • 2018
  • In this study, $MgO-CaO-Al_2O_3-SiO_2$ (MCAS) nanocomposite glass powder having a mean particle size of 50 nm and a specific surface area of $40m^2/g$ is used as a sintering additive for AlN ceramics. Densification behaviors and thermal properties of AlN with 5 wt% MCAS nano-glass additive are investigated. Dilatometric analysis and isothermal sintering of AlN-5wt% MCAS compact demonstrates that the shrinkage of the AlN specimen increases significantly above $1,300^{\circ}C$ via liquid phase sintering of MCAS additive, and complete densification could be achieved after sintering at $1,600^{\circ}C$, which is a reduction in sintering temperature by $200^{\circ}C$ compared to conventional $AlN-Y_2O_3$ systems. The MCAS glass phase is satisfactorily distributed between AlN particles after sintering at $1,600^{\circ}C$, existing as an amorphous secondary phase. The AlN specimen attained a thermal conductivity of $82.6W/m{\cdot}K$ at $1,600^{\circ}C$.

비대칭 MQW 구조를 이용한 Deep-UV LED의 전기적/광학적 특성 (Analysis of Electrical/optical Characteristics Using Asymmetric MQW Structures for Deep-UV LEDs)

  • 손성훈;김수진;김태근
    • 대한전자공학회논문지SD
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    • 제49권5호
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    • pp.10-15
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    • 2012
  • 본 논문에서는 고효율 고출력 DUV(Deep Ultra Violet)-LED(Light Emitting Diodes)의 구현을 위하여 n-side에서 p-side로 well 두께를 다르게 형성하는 비대칭 MQW 에피구조를 제안하였다. 제안된 구조의 물리적 해석을 위해 상용화된 3차원 시뮬레이터 SimuLEDTM을 이용하여 소자의 전기적/광학적 특성을 비교 분석 하였다. 시뮬레이션 결과, 본 연구에서 제안한 B구조(n-side에서 p-side 방향으로 well 두께를 2 nm, 3 nm, 4 nm 로 제작)의 에피층을 가지는 UV-LED는 기본 MQW 에피구조를 가지는 UV-LED와 동작전압은 8.9 V로 동일한 값을 가졌지만 광출력은 기본구조의 10.6 mW 에 비해 약 1.17배 향상된 12.4 mW의 값을 가지는 것을 확인하였다.

Y2O3 함량과 소결조건에 따른 상압소결 AlN 세라믹스의 열전도도 고찰 (Observation of Thermal Conductivity of Pressureless Sintered AlN Ceramics under Control of Y2O3 Content and Sintering Condition)

  • 나상문;고신일;이상진
    • 한국세라믹학회지
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    • 제48권5호
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    • pp.368-372
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    • 2011
  • Aluminum nitride (AlN) has excellent thermal conductivity, whereas it has some disadvantage such as low sinterability. In this study, the effects of sintering additive content and sintering condition on thermal conductivity of pressureless sintered AlN ceramics were examined on the variables of 1~3 wt% sintering additive ($Y_2O_3$) content at $1900^{\circ}C$ in $N_2$ atmosphere with holding time of 2~10 h. All AlN specimens showed higher thermal conductivity as the $Y_2O_3$ content and holding time increase. The formation of secondary phases (yttrium aluminates) by reaction of $Y_2O_3$ and $Al_2O_3$ from AlN surface promoted the thermal conductivity of AlN specimens, because the secondary phases could reduce the oxygen contents in AlN lattice. Also, thermal conductivity was increased by long sintering time because of the uniform distribution and the elimination of the secondary phases at the grain boundary by the evaporation effect during long holding time. A carbothermal reduction reaction was also affected on the thermal conductivity. The thermal conductivity of AlN specimens sintered at $1900^{\circ}C$ for 10 h showed 130~200W/mK according to the content of sintering additive.

반응성 RF 마그네트론 스퍼터링에 의한 AlN 박막 제조 및 유압 감지 특성 (Fabrication of AlN Thin Film by Reactive RF Magnetron Sputtering and Sensing Characteristics of Oil Pressure)

  • 석혜원;김세기;강양구;홍연우;이영진;주병권
    • 한국전기전자재료학회논문지
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    • 제27권12호
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    • pp.815-819
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    • 2014
  • Aluminum nitride (AlN) thin film and TiN film as a buffer layer were deposited on INCONEL 600 substrate by reactive RF magnetron sputtering at room temperature(R.T.) under 25~75% $N_2/Ar$ atmosphere. The as-deposited AlN films at 25~50% $N_2/Ar$ showed a polycrystalline phase of hexagonal AlN, and an amorphous phase. The peak of AlN (002) plane, which was determinant on a performance of piezoelectric transducer, became strong with increasing the $N_2/Ar$ ratio. Any change in the preferential orientation of the as-deposited AlN films was not observed within our $N_2$ concentration range. The piezoelectric sensing properties of AlN module were performed using pressure-voltage measurement system. The output signal voltage of AlN module showed a linear behavior between 20~80 mV in 1~10 MPa range, and the pressure-sensing sensitivity was calculated as 3.6 mV/MPa.

AlN 세라믹의 hot pressing에 사용되는 Y2O3 및 Al2O3 소결조제의 효과 (Effects of Y2O3 and Al2O3 Addition on the Properties of Hot Pressed AlN Ceramics)

  • 공만식;홍현선;이성규;서민혜;정항철
    • 한국재료학회지
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    • 제17권10호
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    • pp.560-566
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    • 2007
  • AlN plates were fabricated by hot pressing at $1700-1900^{\circ}C$ using yttria and alumina (3 and $10\;{\mu}m$ particle size) powders as additives and characterized: density, thermal conductivity, transverse rupture strength, and grain size measurement by SEM and EDS. Density values of $3.31-3.34\;g/cm^3$ are largely attributed to hot pressing of powder mixtures in carbon mold under $N_2$ atmosphere which caused effective degree of oxygen removal from yttrium-aluminate phase expected to form at $1100^{\circ}C$. The grain size of hot pressed AlN was almost homogeneous, with size approximately from 3.2 to $4.0\;{\mu}m$ after hot pressing. $Al_2O_3$ powder of $3\;{\mu}m$ particle size resulted in better transverse rupture strength and finer grain size compared to $10\;{\mu}m$ $Al_2O_3$ powder. The thermal conductivity of AlN ranged between $83-92.7\;W/m{\cdot}K$ and decreased with $Al_2O_3$ addition. Fine grain size is preferred for better mechanical properties and thermal conductivity.

NH3를 이용한 반응성 증착법에 의한 AlN 박막의 우선배향특성에 관한 연구 (A Study on the Preferred Orientation Characteristics of AlN Thin Films by Reactive Evaporation Method using NH3)

  • 오창섭;한창석
    • 대한금속재료학회지
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    • 제50권1호
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    • pp.78-85
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    • 2012
  • Aluminum nitride(AlN) is a compound (III-V group) of hexagonal system with a crystal structure. Its Wurzite phase is a very wide band gap semiconductor material. It has not only a high thermal conductivity, a high electrical resistance, a high electrical insulating constant, a high breakdown voltage and an excellent mechanical strength but also stable thermal and chemical characteristics. This study is on the preferred orientation characteristics of AlN thin films by reactive evaporation using $NH_3$. We have manufactured an AlN thin film and then have checked the crystal structure and the preferred orientation by using an X-ray diffractometer and have also observed the microstructure with TEM and AlN chemical structure with FT-IR. We can manufacture an excellent AlN thin film by reactive evaporation using $NH_3$ under 873 K of substrate temperature. The AlN thin film growth is dependent on Al supplying and $NH_3$ has been found to be effective as a source of $N_2$. However, the nuclear structure of AlN did not occur randomly around the substrate a particle of the a-axis orientation in fast growth speed becomes an earlier crystal structure and is shown to have an a-axis preferred orientation. Therefore, reactive evaporation using $NH_3$ is not affected by provided $H_2$ amount and this can be an easy a-axis orientation method.

MgO-CaO-Al2O3-SiO2 glass 첨가제 함량이 AlN의 물성에 미치는 영향 (Effect of MgO-CaO-Al2O3-SiO2 Glass Additive Content on Properties of Aluminum Nitride Ceramics)

  • 김경민;백수현;류성수
    • 한국분말재료학회지
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    • 제25권6호
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    • pp.494-500
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    • 2018
  • In this study, the effect of the content of $MgO-CaO-Al_2O_3-SiO_2$ (MCAS) glass additives on the properties of AlN ceramics is investigated. Dilatometric analysis and isothermal sintering for AlN compacts with MCAS contents varying between 5 and 20 wt% are carried out at temperatures ranging up to $1600^{\circ}C$. The results showed that the shrinkage of the AlN specimens increases with increasing MCAS content, and that full densification can be obtained irrespective of the MCAS content. Moreover, properties of the AlN-MCAS specimens such as microhardness, thermal conductivity, dielectric constant, and dielectric loss are analyzed. Microhardness and thermal conductivity decrease with increasing MCAS content. An acceptable candidate for AlN application is obtained: an AlN-MCAS composite with a thermal conductivity over $70W/m{\cdot}K$ and a dielectric loss tangent (tan ${\delta}$) below $0.6{\times}10^{-3}$, with up to 10 wt% MCAS content.

다양한 질소분압에서 펄스레이저법으로 성장된 AlN박막의 특성 (Characterization of AlN Thin Films Grown by Pulsed Laser Deposition with Various Nitrogen Partial Pressure)

  • 정준기;하태권
    • 소성∙가공
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    • 제28권1호
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    • pp.43-48
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    • 2019
  • Aluminum nitride (AlN) is used by the semiconductor industry, and is a compound that is required when manufacturing high thermal conductivity. The AlN films with c-axis orientation and thermal conductivity characteristic were deposited by using the Pulsed Laser Deposition (PLD). The AlN thin films were characterized by changing the deposition conditions. In particular, we have researched the AlN thin film deposited under optimal conditions for growth atmosphere. The epitaxial AlN films were grown on sapphire ($c-Al_2O_3$) single crystals by PLD with AlN target. The AlN films were deposited at a fixed temperature of $650^{\circ}C$, while conditions of nitrogen ($N_2$) pressure were varied between 0.1 mTorr and 10 mTorr. The quality of the AlN films was found to depend strongly on the $N_2$ partial pressure that was exerted during deposition. The X-ray diffraction studies revealed that the integrated intensity of the AlN (002) peak increases as a function the corresponding Full width at half maximum (FWHM) values decreases with lowering of the nitrogen partial pressure. We found that highly c-axis orientated AlN films can be deposited at a substrate temperature of $650^{\circ}C$ and a base pressure of $2{\times}10^{-7}Torr$ in the $N_2$ partial pressure of 0.1 mTorr. Also, it is noted that as the $N_2$ partial pressure decreased, the thermal conductivity increased.

Low-Temperature Sintering Behavior of Aluminum Nitride Ceramics with Added Copper Oxide or Copper

  • Hwang, Jin-Geun;Oh, Kyung-Sik;Chung, Tai-Joo;Kim, Tae-Heui;Paek, Yeong-Kyeun
    • 한국세라믹학회지
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    • 제56권1호
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    • pp.104-110
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    • 2019
  • The low-temperature sintering behavior of AlN was investigated through a conventional method. $CaF_2$, CuO and Cu were selected as additives based on their low melting points. When sintered at $1600^{\circ}C$ for 8 h in $N_2$ atmosphere, a sample density > 98% was obtained. The X-ray data indicated that eutectic reactions below $1200^{\circ}C$ were found. Therefore, the current systems have lower liquid formation temperatures than other systems. The liquid phase showed high dihedral angles at triple grain junctions, indicating that the liquid had poor wettability on the grain surfaces. Eventually, the liquid was likely to vaporize due to the unfavorable wetting condition. As a result, a microstructure with clean grain boundaries was obtained, resulting in higher contiguity between grains. From EDS analysis, oxygen impurity seems to be well removed in AlN lattice. Therefore, it is believed that the current systems are beneficial for reducing sintering temperature and improving oxygen removal.

$Y_2O_3$ 첨가와 소결 시간이 AlN 세라믹스의 일축 가압 소결 거동 및 열전도도에 미치는 영향 (Effects of $Y_2O_3$ addition and sintering time on denazification and thermal conductivity of AlN ceramics during hot-press sintering)

  • 채재홍;박주석;안종필;김경훈;이병하
    • 한국결정성장학회지
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    • 제18권6호
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    • pp.237-241
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    • 2008
  • AlN 소결체를 제조함에 있어서 $Y_2O_3$를 소결 첨가제로 하여 일축 가압 소결법을 적용하여 소결 조제 첨가량의 변화와 소결 시간의 변화에 따른 소결 특성, 미세구조 및 열전도도 측성에 대하여 조사하였다. $Y_2O_3$의 첨가로 인하여 AlN의 치밀화가 첨가하지 않은 경우보다 증진됨을 확인할 수 있었으며, 결정립계 및 결정립계 삼중점에서 YAG 이차상을 형성함으로써 AlN 결정 격자 내의 산소 결함 농도를 낮춰 열전도도를 향상시킴을 알 수 있었다. 특히, 소결 시간을 증대함에 따라 결정립 성장 및 열전도도의 방해 요소인 YAG 이차상이 고온에서 휘발됨에 따라 열전도도가 크게 향상됨을 확인할 수 있었다.