• The Korean Journal of Ceramics
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• 제5권3호
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• pp.211-216
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• 1999

Four different $\beta-Si_3N_4$ ceramics with silicon oxynitrides $[Y_10(SiO_4)_6N_2, Yb_4Si_2N_2O_7, Er_2Si_3N_4O_3, \;and La_{10}(SiO_4)_6N_2$, respectivley] as secondary phases have been fabricated by hot-pressing the $Si_3N_4-Re_4Si_2N_2O_7$ (Re=Y, Yb, Er, and La) compositions at $1820^{\circ}C$ for 2h under a pressure of 25 MPa. The high temperature strength and oxidation behavior of the hot-pressed ceramics were characterized and compared with those of the ceramics fabricated from $Si_3N_4-Si_2O_7$ compositions. The $Si_3N_4-Re_4Si_2N_2O_7$composition investigated herein showed comparable high temperature strength to those from $Si_3N_4-Re_2Si_2O_7$ compositions. Si3N4 ceramics from a $Si_3N_4-Y_4Si_2N_2O_7$ composition showed the highest strength of 877 MPa at $1200^{\circ}C$ among the compositions. All $Si_3N_4$ ceramics investigated herein showed a parabolic weight gain with oxidation time at $1400^{\circ}C$ and the oxidation products of the ceramics were $SiO_2$ and $Re_2Si_2O_7$. The $Si_3N_4-Re_4Si_2N_2O_7$ compositions showed inferior oxidation resistance to those from $Si_3n_4-Re_2Si_2O_7$ compositions, owing to the incompatibility of the secondary crystalline phases of those ceramics with $SiO_2$, the oxidation product of Si3N4.Si3N4 ceramics from a $Si_3N_4-Er_4Si_2N_2O_7$ composition showed the best oxidation resistance of 0.375mg/$\textrm{cm}^2$ after oxidation at $1400^{\circ}C$ for 102 h in air among the compositions.

• 한국안광학회지
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• 제13권1호
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• pp.53-58
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• 2008

목적: 안경렌즈용 소형 suptter coating system을 설계하고 제작하고자 한다. 방법: sputter system의 target 설계에 있어서 Essential Macleod thinfilm design software를 이용해 AR 코팅과 mirror 코팅이 동시에 설계 가능한 Si target 을 결정하였으며. 그 후 sputtering 장비를 제작하였다. 결과: $SiO_2$와 $Si_3N_4$의 5층 박막으로 구성되는 AR 코팅의 최적조건은 [air|$SiO_2$(81.3)|$Si_3N_4$(102)|$SiO_2$(19.21)|$Si_3N_4$(15.95)| $SiO_2$(102)|glass] 이였다. Mirror 코팅의 경우, blue color 코팅의 최적조건은 [air|$SiO_2$(56.61)|$Si_3N_4$(135.86)|$SiO_2$(67.64)| $Si_3N_4$(55.4)|$SiO_2$ (53.53)|$Si_3N_4$(51.28)|glass] 이고, green color 코팅의 최적조건은 [air|$SiO_2$(66.2)|$Si_3N_4$(22.76)|$SiO_2$(56.58)| $Si_3N_4$(140.35) |$SiO_2$(152.35)|$Si_3N_4$(70.16)|$SiO_2$(121.87)|glass] 이였으며, gold color 코팅의 최적조건은 [air|$SiO_2$(83.59)|$Si_3N_4$(144.86) |$SiO_2$(11.82)|$Si_3N_4$(129.93)|$SiO_2$(90.01)|$Si_3N_4$(88.37)|glass] 이였다. 결론: 코팅 시간을 줄여 안경단가를 줄이기 위하여 안경렌즈 코팅 시 렌즈의 전 후면을 동시에 코팅을 해야 하기 때문에 sputtering장비 설계를 할 때 안경렌즈 전면과 후면에 동일하게 Si target을 갖춘 cathode를 사용하였고, 렌즈의 곡률을 고려하여 각 층이 동일하게 코팅이 되어야 하기 때문에 target-substrate 간의 간격은 12.5 cm에서 20 cm로 가변할 수 있도록 설계하고 제작하였다. 고품질의 안경렌즈 코팅을 위하여 고진공 펌프로 turbo pump를 이용하였으며, 코팅박막의 균일함을 얻기 위해서 치구를 회전할 수 있도록 설계하고 제작하였다.

• 한국세라믹학회지
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• 제38권12호
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• pp.1150-1154
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• 2001

플라즈마 화학기상증착(PECVD)법을 이용하여 실리카 광도파막의 코어로 이용되는 규소질산화막(SiON)을 Si 웨이퍼 위에 SiH$_4$,$N_2$O, $N_2$가스를 혼합하여 저온(32$0^{\circ}C$)에서 증착하였다. Prism coupler 측정을 통해 SiON 굴절률 1.4663~1.5496을 얻었으며, SiH$_4$/($N_2$O+$N_2$) 유량비와 rf power가 각각 0.33과 150W에서 8.67$mu extrm{m}$/h의 증착률을 나타내었다. 또한 SiH$_4$/($N_2$O+$N_2$) 유량비가 감소함에 따라 SiON막의 roughness는 41~6$\AA$까지 감소하였다.

• 한국전기전자재료학회논문지
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• 제25권1호
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• pp.44-47
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• 2012

The $TiO_2/Si_3N_4/Ag/Si_3N_4/TiO_2$ multi layered structure was designed for the possible application of transparent electrodes in PDP (Plasma Display Panel). Multi layered film was deposited on a glass substrate at room temperature by DC/RF magnetron sputtering system and EMP (Essential Macleod Program) was adopted to optimize the optical characteristics of film. During the deposition process, the Ag layer in $TiO_2/Ag/TiO_2$ became heavily oxidized and the filter characteristic was degraded easily. In thus study, Si3N4 layer was used as a diffusion buffer layer between $TiO_2$ and Ag. in order to prevent the oxidation of Ag layer in $TiO_2/Si_3N_4/Ag/Si_3N_4/TiO_2$ structure. It was confirmed that $Si_3N_4$ layer is one of candidate materials acting as diffusin barrier between $TiO_2/Ag/TiO_2$.

• 대한기계학회논문집A
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• 제33권7호
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• pp.652-657
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• 2009

Strength characteristics of $Si_3N_4$ composite ceramics has been studied as functions of heat-treatment temperature and additive $SiO_2$. $SiO_2$ colloidal could significantly increase the bending strength. Crack healing temperature decreased 300 K by additive $TiO_2$. Bending strength of specimen added $SiO_2$ is higher than that of non-added $SiO_2$. Moreover, bending strength of specimen with $SiO_2$ colloidal coating is much higher that of non-coated specimen. In in-situ observation, crack-healed specimen at 1,573 K shows phenomenon like a fog on the surface. By SPM, both crack-healed specimen, non-coating and coating of $SiO_2$ colloidal, at 1,273 K were healed completely but both of 1,573 K exist crack. This was made by evaporation of $SiO_2$ at high temperature. Crack-healing materials of $Si_3N_4$ composite ceramics is crystallized $Y_2Si_2O_7$, $Y_2Ti_2O_7$ and $SiO_2$. A large amount of Si and O, and little C were detected by EPMA. Si and O increase but C decreases according to heat treatment temperature. Specimens with additive $SiO_2$ were more detected Si and O than that of non-additive $SiO_2$. Specimen with $SiO_2$ colloidal coatings were much more detected O.

• 한국세라믹학회지
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• 제32권5호
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• pp.617-625
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• 1995

In order to reduce reflectance of soda-lime glass having average reflectance of 7.35% and refractive index of 1.53, single (SiO2), double (SiO2/20SiO2-80ZrO2), and triple (SiO2/ZrO2/75SiO2-25ZrO2) layers were designed and fabricated on the glass substrate by Sol-Gel method. Stble sols of SiO2-ZrO2 binary system for antireflective (AR) coatings were synthesized with tetraethyl orthosilicate (TEOS) and zirconium n-butoxide as precursors and ethylacetoacetate (EAcAc) as a chelating agent in an atmosphere environment. Films were deposited on soda-lime glass at the withdrawal rates of 3~11 cm/min using the prepared polymeric sols by dip-coating and they were heat-treated at 45$0^{\circ}C$ for 10 min to obtain homogeneous, amorphous and crack-free films. In case of SiO2-ZrO2 binary system, refractive index of film increased with an increase of ZrO2 mol%. Designed optical constant of films could be obtained through varying the withdrawal rate. In the visible region (380~780nm), reflectance was measured with UV/VIS/NIR Spectrophotometer. Average reflectances of the prepared single-layer [SiO2 (n=1.46, t=103nm)], double-layer [SiO2 (n=1.46, t=1-4nm)/20SiO2-80ZrO2 (n=1.81, t=82nm)], and triple-layer [SiO2 (n=1.46, t=104nm)/ZrO2 (n=1.90, t=80nm)/75SiO2-25ZrO2 (n=1.61, t=94 nm)] were 4.74%, 0.75% and 0.38%, respectively.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2004년도 춘계학술대회 발표 논문집
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• pp.67-71
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• 2004

400~450nm 파장 범위의 청색광을 검출하는 Si 포토다이오드에서 $SiO_2$, $Si_{3}N_{4}$, $SiO_{2}/Si_{3}N_{4}$를 광반사 방지막으로 사용하는 경우 광반사 방지막의 두께에 따른 표면 광반사 손실을 이론적으로 계산하였다. 400~450nm 청색 파장에서 $SiO_2$, $Si_{3}N_{4}$ 단일막에 대한 최소 광반사 손실은 각각 $d(SiO_2)=700~750{\AA}$ 와 $d(Si_{3}N_{4})=500${\AA}$에서 나타났으며, $SiO_{2}/Si_{3}N_{4}$ 이중막에 대한 최소 광반사 손실은 $d(SiO_{2}/Si_{3}N_{4})=750{\AA}/(180~200){\AA}$에서 나타났다.

• 한국세라믹학회지
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• 제24권1호
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• pp.23-32
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• 1987

Synthesis of high purity ultrafine Si3N4 and ${\beta}$-Sialon powders was investigated via the simultaneous reduction and nitriding of amorphous SiO2, SiO2-Al2O3 system prepaerd by hydrolysis of alkoxides, using carbonablack as a reducing agent. In Si(OC2H5)4-C2H5 OH-H2 O-NH4OH system, hydrolysis rate increased with increasing reaction temperature and pH. Pure ${\alpha}$-Si3N4 was formed at 1350$^{\circ}C$ for 5 hrs in N2 atmosphere. In Si(OC2H5)4-Al(OC3H7)3-C6H6-H2 O-NH4OH system, weight loss increased as Si/Al ratio decreased. Single phase ${\beta}$-Sialon consisted of Si/Al=2 was formed at 1350$^{\circ}C$ in N2 and minor phases of ${\alpha}$-Si3N4, AIN, and X-phase were existed besides theSialon phase at other Si/Al ratios. The Si3N4 and Sialon powders synthesized from alkoxides consisted of uniform find particles of 0.05-0.2$\mu\textrm{m}$ in diameter, respectively.

• 한국세라믹학회지
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• 제37권3호
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• pp.280-287
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• 2000

Adsorption behavior and amount of phenolic resin followed silica (SiO2) formation onto silicon nitride(Si3N4) surface were investigated using electrokinetic sonic amplitude (ESA) technique and with UV spectrometer, to fabricate Si3N4/SiC nano-composite based on reaction between SiO2 formed and phenolic resin absorbed onto Si3N4 particle. The amount of SiO2 formed and carbon from phenolic resin absorbed onto Si3N4 surface were calculated quantitatively to adjust the reaction between SiO2 and phenolic resin, resulting in no residual SiO2 and carbon. As a result, pre-heated tempeature for optimized reaction was below 25$0^{\circ}C$, in which there was no residual SiO2 and carbon.

• 한국세라믹학회지
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• 제26권1호
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• pp.31-36
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• 1989

In order to synthesize AlN-polytypes from AlN-SiO2-Al2O3 system, composition A (AlN/SiO2/Al2O3=1/0.3/0.05, mole ratio) and composition B(AlN-SiO2-Al2O3=1/0.2/0.05, mole ratio) were used. AlN-polytypes were produced by nitriding the mixture at 175$0^{\circ}C$~190$0^{\circ}C$ under N2 atmosphere. For lower reaction temperature, 15R phase was produced and in the case of higher reaction temperature, AlN phase was only produced. As each composition was heated at 185$0^{\circ}C$ in N2 atmosphere, produced main phases were 15R phase for composition A and 21R phase for composition B respectively. The fracture surfaces of produced reactants showed porous skeleton structure.