• 한국재료학회지
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• 제5권1호
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• pp.3-11
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• 1995

Titanium oxide$(TiO_{2})$ 박막을 금속 알콕사이드 물질인 $(Ti(OC_3H_7)_4$(titanium isopropoxide)를 이용하여 p-Si(100) 기판위에 상압 화학 기상 증착법으로 증착시켰다. $(TiO_{2})$ 박막의 증착기구는 단순경 계층 이론으로 잘 설명되었으며, 화학반응 지배 기구 영역에서 겉보기 활성화 에너지는 18.2kcal/mol이었다. 증착된 박막은 $250^{\circ}C$이상에서 anatase상의 결정질 박막이었으며, 고온에서 열처리를 했을 경우에 rutile상으로 전이하였다. 박막의 상전이에는 열처리 온도외에도 열처리 시간과 박막의 두께가 영향을 미쳤다. 정전용량-전압특성을 조사해 본 결과 전형적인 MOS 다이오드구조의 특성을 보였으며, 비유전율 상수는 약 80정도였다. 제조한 $(TiO_{2})$ 박막의 열처리 공정 후에는 정전용량이 감소하였으며, 첨가물을 사용한 박막은 열처리 전과 같았다. 이때 $V_{FB}$는 -0.5 ~ 1.5V였다. 전기전도 특성을 알아보기 위하여 전류-전압특성을 조사하였으며 증착된 박막의 전도기구는 hopping mechanism이었다. 전기적 특성을 개선하기 위해서 후열처리 방법과 박막 증착시 Nb, Sr을 첨가하였으며, 모두 누설전류의 감소와 정전파괴전압의 증가를 가져왔다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.869-873
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• 2004

[ $Sr_xBa_{1-x}Nb_2O_6$ ] (SBN, $0.25{\leq}x{\leq}0.75$) ceramic is a ferroelectric material with tetragonal tungsten bronze (TTB) type structure, which has a high pyroelectric coefficient, piezoelectric, and a photo refractive properties. In this study, SBN60(x=0.6) thin film was manufactured by ion beam sputtering technique. Using the prepared SBN60 target in $Ar/O_2$ atmosphere as-deposited SBN60 thin film on Pt(100)/$TiO_2/SiO_2/Si$ substrate crystallization and orientation behavior as well as electric properties of SBN60 thin film were examined. SBN60 deposition up to $3000{\AA}$ in thickness, SBN60 thin film was heat-treated at $650^{\circ}C{\sim}800^{\circ}C$. The orientation was shown primarily along (001) plane from XRD pattern where working pressure was $4.3{\times}10^{-4}$ torr. The deposited layer was uniform, preferred orientatin and crystallization behavior resulted in the change of $O_2$ ratio was observed. In electric propertie of Pt/SBN60/Pt thin film capacitor remnant polarization (2Pr) value was $10{\mu}C/cm^2$, the coercive filed (Ec) 50 kV/cm, and the dielectric constant 615, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.160-160
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• 2010

In this work, we investigate ohmic contacts to p-type GaN using a Pt/Cu/Au metallization scheme in order to achieve low resistance and thermally stable ohmic contact on p-GaN. An ohmic contact formed by a metal electrode deposited on a highly doped InGaN/GaN superlattice sturucture on p-GaN layer. The specific contact resistance is $1.56{\times}10^{-6}{\Omega}cm^2$ for the as-deposited sample, $1.35{\times}10^{-4}{\Omega}cm^2$ for the sample annealed at $250^{\circ}C$ and $6.88{\times}10^{-3}{\Omega}cm^2$ for the sample annealed at $300^{\circ}C$.

• 한국전기전자재료학회논문지
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• 제23권5호
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• pp.397-402
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• 2010

In this paper, we studied WVTR(water vapor transmission rate) properties of $Si_3N_4$ thin film that was deposited using TCP-CVD (transformer coupled plasma chemical vapor deposition) method for the possibility of OLED(organic light emitting diode) encapsulation. Considering the conventional OLED processing temperature limit of below $80^{\circ}C$, the $Si_3N_4$ thin films were deposited at room temperature. The $Si_3N_4$ thin films were prepared with the process conditions: $SiH_4$ and $N_2$, as reactive gases; working pressure below 15 mTorr; RF power for TCP below 500 W. Through MOCON test for WVTR, we analyzed water vapor permeation per day. We obtained that WVTR property below 6~0.05 gm/$m^2$/day at process conditions. The best preparation condition for $Si_3N_4$ thin film to get the best WVTR property of 0.05 gm/$m^2$/day were $SiH_4:N_2$ gas flow rate of 10:200 sccm, working pressure of 10 mTorr, working distance of 70 mm, TCP power of 500 W and film thickness of 200 nm. respectively. The proposed results indicates that the $Si_3N_4$ thin film could replace metal or glass as encapsulation for flexible OLED.

• 열처리공학회지
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• 제28권2호
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• pp.63-67
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• 2015

$TiO_2/Ag/TiO_2$ trilayer films were deposited with radio frequency (RF) and direct current (DC) magnetron sputtering onto the glass substrate to consider the influence of Ag interlayer on the optical properties of the films. The thickness of $TiO_2$ films was kept at 24 nm, while the thickness of Ag interlayer was varied as 5, 10, 15, and 20 nm. As-deposited $TiO_2$ single layer films show the optical transmittance of 66.7% in the visible wave-length region and the optical reflectance of 16.5%, while the $TiO_2$ films with a 15 nm thick Ag interlayer show the enhanced optical transmittance of 80.2% and optical reflectance of 77.8%. The carrier concentration was also influenced by Ag interlayer. The highest carrier concentration of $1.01{\times}10^{23}cm^{-3}$ was observed for a 15 nm thick Ag interlayer in $TiO_2/Ag/TiO_2$ films. The observed result means that an optimized Ag interlayer in $TiO_2/Ag/TiO_2$ films enhanced the structural and optical properties of the films.

• 센서학회지
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• 제26권6호
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• pp.438-444
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• 2017

In this paper, we focus on optimization of the in-situ phosphorous (P) doping of low-pressure chemical vapor deposited (LPCVD) poly Si resistors for obtaining near-zero temperature coefficient of resistance (TCR) at temperature range from 25 to $600^{\circ}C$. The deposited poly Si films were annealed by rapid thermal anneal (RTA) process at the temperature range from 900 to $1000^{\circ}C$ for 90s in nitrogen ambient to relieve intrinsic stress and decrease the TCR in the poly Si layer and get the Ohmic contact. After the RTA process, a roughness of the thin film was slightly changed but the grain size and crystallinity of the thin film with the increase in anneal temperature. The film annealed at $1,000^{\circ}C$ showed the behavior of Schottky contact and had dislocations in the films. Ohmic contact and TCR of $334.4{\pm}8.2$ (ppm/K) within 4 inch wafer were obtained in the measuring temperature range of 25 to $600^{\circ}C$ for the optimized 200 nm thick-poly Si film with width/length of $20{\mu}m/1,800{\mu}m$. This shows the potential of in-situ P doped LPCVD poly Si as a resistor for pressure sensor in harsh environment applications.

• 한국재료학회지
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• 제12권12호
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• pp.918-923
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• 2002

In this work, CdTe films were deposited on CdS/ITO/glass substrate by a close spaced sublimation (CSS) method. A $Cu_2$Te layer was deposited on the CdTe film by evaporating $Cu_2$Te powder. Then the samples were annealed for p+ ohmic contact. TEM and XRD analysis showed that $CdTe/Cu_2$Te interface exhibited different forms with various annealing temperature. A good p+ ohmic contact was achieved when the annealing temperature was between $180^{\circ}C$ to $200^{\circ}C$. Best cell efficiency of 12.34% was obtained when post annealing temperature was $200^{\circ}C$ for 5 min. Thermal stress test of the CdS/CdTe cells with carbon back contact showed that the $Cu_2$Te contact was stable at $50^{\circ}C$ in $N_2$ and was slowly degraded at $100^{\circ}C$ in $N_2$. In comparison to the conventional carbon contact, the $Cu_2$Te contact showed a better thermal stability.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.309-310
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• 2005

In the fabrication of high performance red organic light emitting diode, 2-TNA TA [4,4',4" -tris (2-naphthylphenyl- phenylamino)-triphenylamine] as hole injection material and N PH [N,N'-bis (1-naphthyl) -N,N' -diphenyl-1, 1'-biphenyl-4,4'- diamine] as hole transport material were deposited on the ITO (indium tin oxide)/glass substrate by vacuum evaporation, And then, red color emission layer was deposited using Alq3 as a host material and Rubrene (5,6,11,12- tetraphenylnaphthacene) and GDI 4234 as dopants. Finally, small molecular weight OLED with the structure of ITO/2-TNATA/ NPB/Alq3+Rubrene+GDI4234/Alq3/LiF/Al was obtained by in-situ deposition of Alq3, LiF and Al as electron transport material, electron injection material and cathode. respectively. Green OLED fabricated in our experiments showed the color coordinate of CIE(0.65,0.35) and the maximum luminescence efficiency of 2.1 lm/W at 7 V with the peak emission wavelength of 632 nm.

• 자원환경지질
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• 제29권1호
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• pp.25-33
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• 1996

Stable isotopic ratios of the carbonate rocks and chemical compositions of the matrix of pebble bearing phyllitic rocks known as the Hwanggangri Formation, which are in hot debate on their origin such as tillite, debris flow and turbidite, were determined to interpret their depositional environment. Argillaceous matrix of the pebble bearing phyllitic rocks has a high content of CaO (av. 19.5%) and MgO (av. 8.3%), corresponding to calcareous sandy shale. No difference of chemical compositions including trace elements and REE is in the matrices between the Hwanggangri and the Kunjasan Formations. Carbonate rocks from the Okchon zone and outside of the zone range $-2.5{\sim}+6.1$‰ in ${\delta}^{13}C$ and $+5.8{\sim}+25.9$‰ in ${\delta}^{18}O$, indicating normal marine limestone. However, unusally $^{13}C$ enriched carbonate rocks might be deposited in the highly evaporated sedimentary basin. A wide variation of ${\delta}^{18}O$ values is responsible for metamorphism with a $^{18}O$ depleted meteoric water. Isotopic equilibrium temperatures by graphite-calcite geothermometer show a higher metamorphic temperature ($547{\sim}589^{\circ}C$) in the Okchon zone than those ($265{\sim}292^{\circ}C$) in the Samtaesan Formation of the Chosun group. Rhythmic alternation of relatively thin shale with thin limestone in the Kounri Formation is not cherty layer but thin limesilicate bed by metasomatic replacement. Judging from the isotopic and chemical compositions of the carbonate rocks and calcareous matrix of the pebble bearing phyllitic rocks, the Hwangganari Formation was deposited in the shallow marine environment favorable to debris flow.

• Progress in Superconductivity
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• 제8권1호
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• pp.75-80
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• 2006

[ $Yb_2O_3$ ] films were successfully deposited on a cube-textured Ni and(100) $SrTiO_3$(STO) single crystal substrates by metal organic chemical vapor deposition(MOCVD) method using $H_2O$ vapor as an oxidant. $H_2O$ vapor was used in order to avoid the oxidation of Ni substrate. The working pressure and Ar flow rate were 10 Ton and 600 sccm, respectively. $Yb_2O_3$ films on STO were formed at high temperatures above $900^{\circ}C$. While XRD peaks from $Yb_2O_3$ were hardly detected at $900^{\circ}C$, the $Yb_2O_3$(400) texture was developed fur the films grown at deposition temperatures above $950^{\circ}C$. The AEM surface roughness of $Yb_2O_3$ film, grown on STO, was in the range of $6{\sim}10nm$ for the film deposited at $950^{\circ}C$ with a $H_2O$ vapor partial pressure of 5.5 Ton and deposition times of 3 and 5 mins. For cube-textured Ni substrate, both $Yb_2O_3$(222) and $Yb_2O_3$ (400) textures were developed textures at deposition temperatures above $850^{\circ}C$.