• Title, Summary, Keyword: $Si_3N_4$

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Fabrication of MgO(100)/$Si_3N_4/SiO_2/Si_3N_4$/Si Substrate for Pyroelectric IR Sensor (초전형 적외선 센서를 위한 MgO(100)/$Si_3N_4/SiO_2/Si_3N_4$/Si 기판 제작)

  • Kim, Sung-Woo;Sung, Se-Kyoung;Ryu, Jee-Youl;Choi, Woo-Chang;Choi, Hyek-Hwan;Lee, Myoung-Kyo;Kwon, Tae-Ha
    • Journal of Sensor Science and Technology
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    • v.9 no.2
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    • pp.90-95
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    • 2000
  • The substrate for pyroelectric IR sensor which has orientation similar to MgO single crystal was fabricated by depositing the MgO thin film on $Si_3N_4/SiO_2/Si_3N_4$/Si. The MgO thin film was deposited by RF magnetron sputtering. The c-axis orientation of PLT thin film deposited on Pt/MgO(100)/$Si_3N_4/SiO_2/Si_3N_4$/Si substrate was investigated. The MgO thin film deposited at $500^{\circ}C$ at a gas pressure of 30 mTorr with RF power of 160 W exhibited a good a-axis orientation. The PLT thin films deposited on these substrates also exhibited c-axis orientation similar to the PLT thin films deposited on MgO single crystal substrate.

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Microstructure and Mechanical Properties of Ti-Si-C-N Coatings Synthesized by Plasma-Enhanced Chemical Vapor Deposition (PECVD 로 합성된 Ti-Si-C-N 코팅막의 미세구조 및 기계적 성질)

  • Hong, Yeong-Su;Kim, Gwang-Ho
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • pp.83-85
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    • 2008
  • 4성분계 Ti-Si-C-N 코팅막은 $TiCl_4$, $SiH_4$, $CH_4$, Ar, 그리고 $N_2$ 가스 혼합체를 이용하여 RF-PECVD 기법에 의해 Si 와 AISI 304 기판위에 합성하였다. Ti-C-(0.6)-N(0.4) 조성의 코팅막에 Si를 첨가함으로 Ti(C,N) 결정질은 줄어들고, Si3N4 및 SiC 비정질상이 나타났다. Ti-Si(9.2 at.%)-C-N의 조성에서 나노 크기의 nc-Ti(C,N) 결정질을 비정질 a-Si3N4/SiC가 둘러싸고 있는 형태의 나노 복합체를 나타내었다. 경도 24 Gpa의 Ti-C-N 코팅막은 Si를 첨가함으로 Ti-Si(9.2 at.%)-C-N 조성에서 46 Gpa의 최고 경도를 나타내었으며, 마찰계수의 경우에도 Ti-C-N 코팅막에 Si를 첨가함으로 크게 낮아졌다.

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Fabrication and Mechanical Properties of $SiC/Si_3N_4$ Nano Composite Materials ($SiC/Si_3N_4$ 나노 복합체의 제조 및 기계적 특성)

  • Gang, Jong-Bong;Jo, Beom-Rae;Lee, Su-Yeong
    • Korean Journal of Materials Research
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    • v.6 no.4
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    • pp.421-427
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    • 1996
  • 초미립 SiC 분말을 2차상으로 Si3N4에 첨가하여 SiC/Si3N4 나노 복합체를 핫프레스법과 가스압소결고 제조하였다. 2차상으로 첨가한 SiC의 입자 크기가 $\beta$-Si3N4 나노 복합체를 제조할 수 있었다. 사온에서 80$0^{\circ}C$까지는 강도의 100$0^{\circ}C$이상에서는 강도는 급격한 감소를 보였으며 이는 소결조제로 첨가한 AI2O3, Y2O3와 SiO2가 $\beta$-Si3N4의 입계에 유리상을 형성하였기 때문에 해석된다.

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Unipolar resistive switching characteristics of W/Si3N4/Si memory devices with doped silicon bottom electrodes

  • Kim, Sungjun;Park, Byung-Gook
    • Current Applied Physics
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    • v.17 no.2
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    • pp.146-151
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    • 2017
  • In this paper, we report the effects of two different types of dopants (n- and p-type semiconductors) on the unipolar resistive switching characteristics of a fully CMOS-compatible $W/Si_3N_4/Si$ structure. The $W/Si_3N_4/p^+-Si$ device displayed a gradual reset transition, while the $W/Si_3N_4/n^+-Si$ device showed abrupt reset switching. The different reset switching behaviors of the devices can be explained by their different properties immediately before set switching, which were experimentally demonstrated by the statistical relationships between resistive switching parameters such as the set and reset voltages, the set and reset currents, and the resistances of the high resistance state (HRS) and low resistance state (LRS). The different reset switching properties of the devices were further evidenced by the dynamics of the conducting paths in the LRS immediately before reset switching. The $W/Si_3N_4/p^+-Si$ device showed superior resistive switching performance to the $W/Si_3N_4/n^+-Si$ one because of the gradual transition with low reset current. Finally, we demonstrated multi-level switching, which is attractive for application in high-density memory, by altering the reset voltage.

Environmental Influences on Gas pressure Sintering of $Si_3N_4$ (질화규소의 가스압 소결에 미치는 환경 영향)

  • 김인섭;이경희;이병하
    • Journal of the Korean Ceramic Society
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    • v.30 no.4
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    • pp.309-315
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    • 1993
  • Gas pressure sintering is a promising process in various densification methods of high strength Si3N4 ceramics. Environmental influences on gas pressure sintering of Si3N4 was investigated with the variationof packing powder, specimen container and N2 gas pressure. The specimens had higher density, larger weight loss and inhomogeneous color in graphite specimen container than in SN26 crucible. The variations of sintering densities in various packing powders (Si3N4, SN26, AlN, BN) were very small but SiC powder was synthesised in graphite crucible with Si3N4 packing powder, aluminium oxynitride compounds were synthesised in SN26 crucible with AlN packing power. Also N2 gas pressure over 20kg/$\textrm{cm}^2$ reduced the densification of Si3N4 in one step-gas pressure sintering. As the result of two step-gas pressure sintering at 700kg/$\textrm{cm}^2$ for 15min., relative density of 99.9% and 3-point bending strength of 1090MPa and dense microstructure of 3~4${\mu}{\textrm}{m}$ grain size were obtained.

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Effect Of Bedding on the Microstructure of Si3N4 with Ultrafine SiC (초미립 SiC가 첨가된 질화규소에서 미세구조에 미치는 Bedding의 영향)

  • 이홍한;김득중
    • Journal of Korean Powder Metallurgy Institute
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    • v.10 no.1
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    • pp.57-62
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    • 2003
  • The effect of bedding on the microstructure of $Si_3N_4$ added with ultra-fine SiC was investigated. The bedding and the addition of ultra-fine SiC effectively inhibited grain growth of $Si_3N_4$ matrix grain. The microstructures of the specimens sintered with bedding powder consisted of fine-grains as compared with the specimens sintered without bedding powder. In addition, the grain size and the difference of grain size between the specimens sintered with bedding and without bedding was reduced with increasing SiC content. Some ultra-fine SiC particles were trapped in the $Si_3N_4$ grains growed. The number of SiC particles trapped in the $Si_3N_4$ grains increased with increasing the grain growth. When ultra-fine SiC particles were added in the $Si_3N_4$ ceramics, the strength was improved but the toughness was decreased, which was considered to be resulted from the decrease of the grain size.

Microstructure Control and Mechanical Properties of Continuously Porous SiC-Si3N4 Composites (연속다공질 SiC-Si3N4 복합체의 미세구조 및 기계적 특성)

  • Paul Rajat Kanti;Gain Asit Kumar;Lee Hee-Jung;Jang Hee-Dong;Lee Byong-Taek
    • Korean Journal of Materials Research
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    • v.16 no.3
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    • pp.188-192
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    • 2006
  • The microstructures and mechanical properties of continuously porous $SiC-Si_3N_4$composites fabricated by multi-pass extrusion were investigated at different Si levels added. Si-powder with different weight percentages (0%, 5%, 10%, 15%, 20%) was added to the SiC powder to make the raw mixture powders, with $6wt%Y_2O_3-2wt%Al_2O_3$ as sintering additives, carbon ($10-15{\mu}m$) as a pore-forming agent, ethylene vinyl acetate as a binder and stearic acid ($CH_3(CH_2)_{16}COOH$) as a lubricant. In the continuously porous $SiC-Si_3N_4$ composites, $Si_3N_4$ whiskers like the hairs of nostrils were frequently observed on the wall of the pores. In this study, the morphology of the $Si_3N_4$ whiskers was investigated with the silicon addition content. In the composites containing of 10 wt% Si, a large number of $Si_3N_4$ whiskers was found at the continuous pore regions. In the sample to which 15 wt% Si powder was added, maximum values of about 101 MPa bending strength and 57.5% relative density were obtained.

Synthesis and Crystallization of Fine SiC-${Si_3}{N_4}$Composite Powders by the Vapor Phase Reaction (기상반응에 의한 SiC-${Si_3}{N_4}$복합 분말의 제조 및 결정화)

  • Kim, Hyoung-In;Choi, Jae-Moon;Kim, Suk;So, Myoung-Gi
    • Journal of the Korean Ceramic Society
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    • v.37 no.11
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    • pp.1091-1096
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    • 2000
  • 본 연구에서는 기상 반응법을 이용하여 TMS(Tetramethylsilane:Si($CH_3$)$_4$)와 NH$_3$그리고 H$_2$의 혼합기체로부터 반응 온도 1000~120$0^{\circ}C$ 및 입력비(NH$_3$/Si($CH_3$)$_4$) 1~3의 조건에서 초미분의 SiC-Si$_3$N$_4$복합 분말을 합성하였다. 합성되어진 복합 분말들의 결정상의 변화와 평균 입경을 알아보기 위해 XRD와 TEM 분석을 행한 결과, 구형의 비정질 분말이 형성되었으며, 입자의 크기는 약 70~130nm이었다. 입자의 크기는 입력비에 관계없이 거의 일정하였으나 반응 온도가 증가함에 따라서 감소하였다. FT-IR과 EA 분석 결과, 합성되어진 분말은 Si, N, C, 그리고 H로 이루어진 화합물임을 확인할 수 있었다. 또한 입력비가 다른 조건에서 합성되어진 분말을 $N_2$분위기 하에서 155$0^{\circ}C$로 2시간 열처리를 행한 결과, 낮은 입력비인 경우 $\beta$-SiC, $\alpha$-Si$_3$N$_4$$\beta$-Si$_3$N$_4$의 결정상들이 혼재하였으나, 높은 입력비인 경우는 결정화 후 $\alpha$-Si$_3$N$_4$상만이 존재하였다.

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Effects of Carbon-coated SiC Whiskers on the Mechanical Properties of SiC Whisker Reinforced Silicon Nitride Ceramic Composite (SiC 휘스커 강화 질화규소 복합재료의 기계작 성질에 미치는 카본 코팅 SiC 휘스커의 영향)

  • 배인경;이영규;조원승;최상욱;장병국;임실묵
    • Journal of the Korean Ceramic Society
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    • v.36 no.10
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    • pp.1007-1015
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    • 1999
  • The Si3N4 composites reinforced with carbon-coated SiC whiskers were fabricated by hot-pressing at 180$0^{\circ}C$ for 2 hours to examine the effects of carbon-coated whiskers on the mechanical properties of SiC whisker reinforced Si3N4 composites. The flexural strength of the Si3N4 composites and Si3N4 monolith respectively. The weak interfacial bond between carbon-coated SiC whiskers and Si3N4 matrix which enhances the crack deflection and whisker pull-out could contribute to the improvement of mechanical properties of the composites.

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Densification of Ultrafine $Si_3-N_4-SiC$ Powder Compacts by Rapid Heating under Controlled Thermograms (급속가열 이력 제어에 의한 $Si_3-N_4-SiC$계 미분말 시편의 치밀화)

  • 이형직
    • Journal of the Korean Ceramic Society
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    • v.32 no.7
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    • pp.832-838
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    • 1995
  • The densifying behavior of ultrafine amorphous Si3N4 (about 20 nm)-$\beta$-SiC (about 40~80 nm) powders (O2 : 1.3~15wt%, 0$700^{\circ}C$ within 15 sec and then immediately cooled and held at 135$0^{\circ}C$ for 10 min in N2 atmosphere without resorting to additives using a Xe image heating apparatus. Using an ultrafine pure Si3N4 powder with particle size less than 30nm, further more, mixed with an appropriate amount of $\beta$-SiC, was found to be advantageous to obtain uniform and homogeneous microstructure. In addition, ultrafine Si3N4 powders were also proved to be effective as sintering additive on densifying large sized Si3N4 powder compacts.

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