• 한국결정성장학회지
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• 제9권1호
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• pp.1-5
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• 1999

Molecular beam epitaxy법으로 $CaF_{2}$ (111) 기판위에 희토류 이온 ($(Nd^{3+},\;Er^{3+})$) 첨가 $CaF_{2}$ 박막을 성장하였다. 첨가농도와 박막두께에 따른 희토류 첨가 $CaF_{2}$ 박막의 표면구조와 결정성을 RHEED로 검토하였다. 반도체 관련 고집적회로구조에 있어서의 완층막으로서의 응용을 고려하여, 희토류첨가 $CaF_{2}$ 박막과 $CaF_{2}$ (111) 기판과의 격자부정합의 변이를 X-ray rocking Curve 분석에 의해 검토하였다.

• 한국전기전자재료학회논문지
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• 제22권7호
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• pp.584-588
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• 2009

Layered ZnS/$CaF_2$/ZnS/Cu film was deposited on glass substrate by using evaporation method. ZnS and $CaF_2$ were chosen as high and low refractive materials. Cu was used as mid-reflective layer. Reflectance with different optical thickness of $CaF_2$ ranging from $0.25{\lambda}\;to\;0.5{\lambda}$ were systematically investigated by using spectrophotometer. In order to expect the experimental results, the simulation program, the Essential Macleod Program(EMP) was adopted and compared with the experimental data. Based on the results taken by spectrophotometer, the ZnS/$CaF_2$/ZnS/Cu multi-layered thin film show the maximum reflectance of 80% at 625nm $(0.25{\lambda}\;in\;CaF_2)$ and 42% at 660nm $(0.5{\lambda}\;in\;CaF_2)$ respectively. As compared with the experimental results and simulation data, it was confirmed the experimental data is well matched with the EMP data.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.132-132
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• 2012

Depositing $CaF_2$[0.6% lattice-mismatch] on the Si(001)-$4^{\circ}$ off surface [composed of a single (001) domain with regularly-arrayed double-layer DB steps and located between (1 1 19) and (1 1 21)] held at $700^{\circ}C$, $CaF_2$ molecules are preferentially adsorbed on the dimers and dissociated to Ca and F atoms. Dissociated Ca atoms form a silicide layer of a $2{\times}3$ structure on the (001) terrace, while F atoms are desorbed from the surface. Once the terrace is covered with a calcium silicide layer, CaF starts to be adsorbed selectively on the steps, as shown in Fig. (a). With $CaF_2$ deposition exceeding 1 ML, the (1 1 17) surface having 1-D $CaF_2$ nanodots are formed as shown in Fig. (b). By the present STM study, it has been clearly disclosed that the calcium silicide interfacial layer is preformed prior to adsorption of $CaF_2$ on vicinal Si(001) surface.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.242-242
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• 2012

From the combined studies of STM and synchrotron photoemission, it has been found that a $CaF_2$ molecule is dissociated to Ca and F atoms on the $Si(114)-2{\times}1$ held at $500^{\circ}C$ at the initial adsorption stage. The Ca atoms form isolated and unique shapes of silicide molecules as shown in Fig. (a), while the F atoms are desorbed from the surface. On the other hand, beyond a $CaF_2$ coverage of 0.3 monolayer, as shown in Fig. (b), in addition to these silicide molecules, a 1-D facet [composed of (113) and (115) faces] adjacent to an etch pit has been observed, and F atoms are also detected from photoemission. These results imply that F atoms act as an etchant on Si(114) and CaF is adsorbed selectively on the (113) face of this facet. From the present studies, it has been concluded that, an insulating $CaF_2$ layer like that on Si(111) cannot be formed on Si(114), but a CaF-decorated nanofacet with a high aspect-ratio can be grown.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.277-281
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• 2003

Effects of $CaF_2$ addition as a filler on the high frequency dielectric properties and sintering of CaO-$Al_2O_3-SiO_2-B_2O_3$(CASB) and ZnO-MgO-$B_2O_3-SiO_2$(ZMBS) glass composites were investigated. The optimal glass composition in the CASB system was 33.0CaO-$17.0Al_2O_3-35.0SiO_2-15.0B_O_3$(in wt%). The corresponding dielectric properties were k=8.1 and $Q{\times}fo$=1,200GHz. The sintering temperature was $800{\mu}m$. In case of 2MBS system, 25.0ZnO-25.0MgO-20.0$B_2O_3-30.0SiO_2$(in wt%) glass showed k=6.8 and $Q{\times}fo$=5,200GHz when it was sintered at $750^{\circ}C$. The maximum amount of $CaF_2$ in the CASB and 2MBS glass system without any detrimental effect on the sintering was 25.0 v/o and 15.0 v/o, respectively. The addition of $CaF_2$ in the glass systems improved the high frequency dielectric properties. In case of CASB+$CaF_2$ composite, k was 7.1 and $Q{\times}fo$ was 2,300GHz. And in case of 2MBS+$CaF_2$ composite, k was 5.9 and $Q{\times}fo$ was 8,100GHz. $CaF_2$ addition also reduced sintering temperature. Effects of $CaF_2$ on the dielectric and sintering properties was analyzed in terms of viscosity and crystallization behavior changes due to the interaction between $CaF_2$ and the glass systems.

• 자원리싸이클링
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• 제20권4호
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• pp.58-64
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• 2011

고온에서 PCB 처리를 통한 Au, Ag와 같은 귀금속뿐 아니라 Ni과 같은 주요 회유금속을 회수하기 위한 기초연구로서 CaO-$Al_2O_3$(-$SiO_2$) 및 CaO-$SiO_2$-$CaF_2$ 슬래그를 이용하여 Au, Ag, Ni의 회수거동올 관찰하였다. 슬래그 투입 없이 PCB만으로 용융실험을 수행한 결과 PCB는 거의 용융되지 않았으며, 이로부터 유도전류를 이용한 용융을 촉진할 뿐 아니라 유가금속의 회수를 위해서는 Cu와 갇은 적절한 base metal이 필요함을 확인하였다. 본 연구결과, PCB/Cu ratio는 1 이하가 바람직할 것으로 생각된다. CaO-$Al_2O_3$(-$SiO_2$) 및 CaO-$SiO_2$-$CaF_2$ 슬래그를 투입한 결과, $CaF_2$를 함유하는 fluorosilicate계 슬래그가 calcium aluminate계 슬래그보다 융점과 점도가 낮게 제어되었으며, 이로부터 Au, Ag, Ni의 높은 분배비를 얻을 수 있었다. 점도가 낮은 $CaF_2$ 함유 슬래그 적용 시 높은 유가금속 회수율은 슬래그 내에서 각 금속입자의 등속침강속도가 상승하기 때문인 것으로 평가되었다.

• 한국결정성장학회지
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• 제4권1호
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• pp.21-32
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• 1994

Bridgman법에 의해 성장속도를 변화시키면서 $CaF_2$ 결정을 육성시켰으며, 각 성장속도에 따른 이온전도도의 변화를 알아보기 위하여 AC Impedance Analyzer를 사용하여 그 전기적 특성을 고찰하였다. 성장속도가 증가함에 따라 $CaF_2$ 결정은 단결정에서 다결정으로 육성되었으며, 그로인한 여러가지 결함 및 계면의 변화에 따라 이온 전도도는 크게 변화하였다. 또한, $CaF_2$ 결정을 더욱 무질서(disorder)화 시키고 여분의 불소 이온 carrier와 공공(vacancy)을 증가시키기 위하여 $YF_3$를 첨가하여 $Ca_{1-x}Y_XF_{2+X}$ 결정을 얻었으며, $YF_3$의 첨가량의 변화에 따른 $Ca_{1-x}Y_XF_{2+X}$ 결정의 이온전도도의 변화를 조사하였다. $CaF_2$ 결정과 $Ca_{1-x}Y_XF_{2+X}$ 결정의 온도변화에 따른 이온전도도의 변화를 비교하여 결함 clustering이 고체전해질의 전기적 성질에 미치는 영향을 조사하였다.

• 자원리싸이클링
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• 제6권1호
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• pp.11-16
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• 1997

국내에서 발생하는 석탄 비산회로부터 $H_2$$SO_4$과 $CaF_2$을 침출제로 사용하여 알루미늄을 추출하나느 연구를 수행하였다. $H_2$$SO_4$과 $CaF_2$를 반응시켜 비산회의 주성분인 mullite를 분해하는 HF를 생성하여 효과적인 알루미늄의 추출을 유도하였다. $H_2$$SO_4$과 $CaF_2$농도, 반응온도 및 반응시간 등의 실험변수가 알루미늄의 침출에 미치는 영향을 조사하였으며 광액농도 5%m $106^{\circ}C$에서 4M $H_2$SO$_4$와 0.5M $CaF_2$의 조건으로 10시간 침출하여 최고 97%의 알루미늄 추출율을 얻을 수 있었다.

• The Korean Journal of Ceramics
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• 제4권3호
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• pp.204-206
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• 1998

The Gibbs free energy of formation of $BaThO_3$ from elemental oxides has been measured at temperatures between 853 and 903 K using a $CaF_2$ solid electrolyte galvanic cell. The galvanic cell consisted of Pt, $O_2, CaO+CaF_2 \parallel CaF_2 \parallelBaThO_3+ThO_2+BaF_2, O_2$, Pt EMF gave the standard Gibbs free energy for the reaction $CaF_2+BaThO_3=CaO+BaF_2+ThO_3$ as $\DeltaG^o$,/TEX>=124111.031-117.597 T(J/mol).

• 한국전기전자재료학회논문지
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• 제11권12호
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• pp.1122-1127
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• 1998

Group II-AF_2$films such as $CaF_2$, $SrF_2$, and $BaF_2$ have been commonly used many practical applications such as silicon on insulatro(SOI), three-dimensional integrated circuits, buffer layers, and gate dielectrics in filed effect transistor. This paper presents electrical and structural properties of fluoride films as a gate dielectric layer. Conventional gate dielectric materials of TFTs like oxide group exhibited problems on high interface trap charge density($D_it$), and interface state incorporation with O-H bond created by mobile hydrogen and oxygen atoms. To overcome such problems in conventional gate insulators, we have investigated $CaF_2$ films on Si substrates. Fluoride films were deposited using a high vacuum evaporation method on the Si and glass substrate. $CaF_2$ films were preferentially grown in (200) plane direction at room temperature. We were able to achieve a minimum lattice mismatch of 0.74% between Si and $CaF_2$ films. Average roughness of $CaF_2$ films was decreased from 54.1 ${\AA}$ to 8.40 ${\AA}$ as temperature increased form RT and $300^{\circ}C$. Well fabricated MIM device showed breakdown electric field of 1.27 MV/cm and low leakage current of $10^{-10}$ A/$cm^2$. Interface trap charge density between $CaF_2$ film and Si substrate was as low as $1.8{\times}10^{11}cm^{-2}eV^{-1}$.