• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.128-128
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• 2011

TTFT-LCD에 투명전극으로 사용되고 있는 IGZO 박막의 특성을 조사하기 위하여 RF magnetron sputtering을 이용하여 Ar Gas 유량 변화에 따른 IGZO 박막을 유리 기판 위에 제작하고 투명전극의 구조적, 광학적, 전기적 특성을 조사하였다. 소결된 타겟으로는 In:Ga:ZnO를 각각 1 : 1 : 2 mol%의 조성비로 혼합하여 이용하였으며, 30mm${\times}$30 mm의 Corning1737 유리기판에 Sputtering 방식으로 증착 하였다. 장비 조건으로는 Rf power를 25 W로 고정 시켰으며, 실험변수로는 초기합력은 $2.0{\times}10^{-6}$ Torr 이하로 하였으며, 증착압력은 $9.0{\times}10^{-3}$ Torr로 하였다. Ar Gas를 30, 50, 70, 90 sccm으로 변화를 주어 실험을 진행하였다. 증착온도는 실온으로 고정하였다. 분석 결과로는 Ar Gas가 30 sccm일 때 AFM분석결과 0.3 nm 이하의 Roughness를 가졌으며, XRD분석결과 34$^{\circ}$ 부근에서 (002) c-축 방향성 구조임을 확인할수 있었다. UV-Visible-NIR 측정결과 가시광선 영역에서 80% 이상의 투과도를 만족 시켰으며, Hall 측정결과 Carrier concentration $2.7{\times}10^{19}\;cm^{-3}$, Mobility 8.4 $cm^2/v_{-s}$이며, Resistivity $8.86{\times}10^{-3}$, 투명전극으로 사용 가능함을 확인할 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.370-370
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• 2012

Feature size of Cu interconnects keep shrinking into several tens of nanometer level. For this reason, the Cu interconnects face challenging issues such as increase of electro-migration, line-width dependent electrical resistivity increase, and gap-filling difficulty in high aspect ratio structures. As the thickness of the Cu film decreases below 30 nm, the electrical resistivity is not any more constant, but rather exponential. Research on alloying with other elements have been started to inhibit such escalation in the electrical resistivity. A faint trace of Al added in Cu film by sputtering was reported to contribute to suppression of the increase of the electrical resistivity. From an industrial point of view, we introduced cyclic metal organic chemical vapor deposition (MOCVD) in order to control Al concentration in the Cu film more easily by controlling the delivery time ratio of Cu and Al precursors. The amount of alloying element could be lowered at level of below 1 at%. Process of the alloy formation was applied into gap-filling to evaluate the performance of the gap-filling. Voidless gap-filling even into high aspect ratio trenches was achieved. In-depth analysis will be discussed in detail.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.309-309
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• 2012

Heteroepitaxial growth remains as one of the continuously growing interests, because the heterogeneous crystallization on different substrates is a common feature in the fabrication processes of many semiconductor materials and devices, such as molecular beam epitaxy, pulsed laser deposition, sputtering, chemical bath deposition, chemical vapor deposition, hydrothermal synthesis, vapor phase transport and so on [1,2]. By using the R.F. sputtering system, ZnO thin films were deposited on graphene 4 and 6 mono layers, which is grown on 400 nm and 600 nm $SiO_2$ substrates, respectively. The ZnO thin layer was deposited at various temperatures by using a ZnO target. In this experimental, the working power and pressure were $3{\times}10^{-3}$ Torr and 50 W, respectively. The base pressure of the chamber was kept at a pressure around $10^{-6}$ Torr by using a turbo molecular pump. The oxygen and argon gas flows were controlled around 5 and 10 sccm by using a mass flow controller system, respectively. The structural properties of the samples were analyzed by XRD measurement. The film surface and carrier concentration were analyzed by an atomic force microscope and Hall measurement system. The surface morphologies were observed using field emission scanning electron microscope (FE-SEM).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.156-156
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• 2011

Nanocrystalline $Ca_2Gd_8Si_6O_{26}$ (CGS) : $Sm^{3+}$ and CGS : $Tb^{3+}/Sm^{3+}$ phosphors were prepared by solvothermal reaction method for light emitting diode (LED) and field emission display (FED) applications. The XRD patterns of these phosphors confirmed their oxyapatite structure in the hexagonal lattice. The visible luminescence properties of these phosphors were investigated by exciting with ultraviolet (UV) or near-UV light and low voltage electron beam. The photoluminescence (PL) properties of $Ca_2Gd_8Si_6O_{26}$ (CGS) : $Sm^{3+}$ and CGS : $Tb^{3+}/Sm^{3+}$ phosphors were investigated as a function of $Sm^{3+}$ concentration. Cathodoluminescence (CL) properties were examined by changing the acceleration voltage. The CGS : $Sm^{3+}$ showed the dominant orange emission due to the $^4G_{5/2}{\rightarrow}^6H_{7/2}$ transition. The CGS : $Tb^{3+}/Sm^{3+}$ phosphor showed the green, white and orange emissions when excited with 275, 378, and 405 nm wavelengths, respectively. The chromaticity coordinates of these phosphors were comparable to or better than those of standard phosphors for LED or FED devices.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.367-367
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• 2012

TTFT에 투명반도체로 사용되고 있는 IGZO 박막의 특성을 조사하였다. IGZO박막은 비정질임에도 불구하고 높은 이동도를 가지는 것으로 알려져 있다. 본 실험에서는 RF magnetron sputtering법을 이용하여 Ar Gas 유량 변화에 따른 IGZO 박막을 유리 기판 위에 제작 하였고 투명반도체의 구조적, 광학적, 전기적 특성을 조사하였다. 소결된 타겟 으로는 In:Ga:ZnO를 각각 1:1:2mol%의 조성비로 혼합하여 이용하였으며, $30{\times}30mm$의 XG Glass 유리기판에 Sputtering 방식으로 증착하였다. 공정 조건으로는 초기합력은 $2.0{\times}10^{-6}Torr$이하로 하였으며, 증착 압력은 $2.0{\times}10^{-2}Torr$로 하였다. Rf power를 75 W로 고정시켰다. 실험 변수로는 Ar Gas를 25, 50, 75, 100 sccm으로 변화를 주어 실험을 진행하였으며, 증착온도는 실온으로 고정하였다. 분석 결과로는 Ar Gas가 75 sccm일 때 XRD분석결과 $34^{\circ}$ 부근에서 (002) c-축 방향성 구조임을 확인할 수 있었으며, AFM분석결과 0.3 nm이하의 Roughness를 가졌다. UV-Visible-NIR 측정결과 가시광선 영역에서 85%이상의 투과도를 만족 시켰으며, Hall 측정결과 Carrier concentration $8.3{\times}101^{19}cm-^{-3}$, Mobility $12.3cm^2/v-s$이며, Resistivity $0.6{\times}10^{-2}{\Omega}-cm$, 투명반도체로 사용 가능함을 확인 할 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.390-390
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• 2011

The size distribution of gold nanoparticles (NPs) is an important factor in their application to various fields of nanotechnology such as nanodevice fabrication, nanobio measurements, medical diagnosis, and so on, since the properties of nanoparticles depend on the size. As the pH of the reaction mixture was increased, the size distribution of gold NPs synthesized via sodium citrate reduction method was getting narrower and it finally became quite mono-dispersive when the pH was higher than ca. 7. 0.1M NaOH solution was used in controlling the pH, while the ratio between sodium citrate and HAuCl4 was fixed to 3:1 whose initial pH was about 5. Scanning and tunneling electron microscopy and UV/Vis spectrometry were used to characterize the resulting Au NPs. The change of the size distribution of the NPs was discussed with the change of the reaction rate related to the change of hydroxyl ion concentration.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.675-675
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• 2013

CIGS thin films have received a great attention as a promising material for solar cells due to their high absorption coefficient, appropriate bandgap, long-term stability, and low cost production. CIGS thin films have been deposited by various methods such as co-evaporation, sputtering, spray pyrolysis and electro-deposition. In this study, Cu(In,Ga)Se2(CIGS) thin films were prepared using a single quaternary target by rf magnetron sputtering. The effect of sulfurization on the structural, compositional and electrical properties of the films was examined in order to develop the deposition process. An optimal sulfurization process will be selected for the preparation of CIGS thin films with good structural, optical and electrical properties by applying various sulfurization processes. In addition, the electrical properties of CIGS thin films were investigated by post-deposition annealing process. The carrier concentration of CIG(SSe) thin films after sulfurization was increased from $10^{14}cm^{-3}$ to $10^{16}cm^{-3}$ and the resistivity was increased from 10 ${\Omega}cm$ to $10^3$ ${\Omega}cm$. It is confirmed that CIG(SSe) thin films prepared at optimal deposition condition have similar atomic ratio to the target value after sulfurization.

• 한국진공학회지
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• 제8권2호
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• pp.165-171
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• 1999

Diamond-like carbon(DLC) films were synthesized using the rf-plasma CVD technique with the addition of small amounts of nitrogen and oxygen to a gas mixture of $CH_4$ and $H_2$. The gas flow ratio of $CH_4$ to $H_2$ was 2.4:1, and 3% , 13.6% of nitrogen were added to the gas mixture of $CH_4$ and $H_2$ for the deposition of DLC films. The film stress tended to decrease as the nitrogen concentration increased from 3% to 13.6%, probably due to the decrease of the number of the interlink between carbon atoms. The residual stress tended to slightly decrease when 3% of oxygen was added. Scratch tests were performed to investigate the adhesion between the DLC films and the Ti intelayer after pretreating the TiN surface with direct hydrogen plasma. The adhesion was enhanced by adding nitrogen and oxygen to the $CH_4$ and $H_2$ gas mixture. The adhesion for the 3% nitrogen addition was better than that for the 13.6% nitrogen addition. The Vicker's hardness of the DLC films was measured to be 1100Hv.

• 한국진공학회지
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• 제7권s1호
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• pp.160-166
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• 1998

The field emission characteristics of defective diamond films grown by microwave plasma enhanced chemical vapor deposition (MPECVD) have been studied. X-ray diffraction, the poor crystal quality and/or small grain sizes of the diamond phase and the inclusion of the non-diamond carbon phases in these films have been condirmed by raman spectroscopy, scanning electron microscopy, atomic force microscopy, and the reflectance measurements. The degrees of the film defectiveness and the emission characteristics were dependent on the methane concentration. Current-versus-voltage measurements have demonstrated that the defective diamond films have good electron emission characteristics. characteristics strongly suggests the defect-related electron-emission mechanism. The defective diamond films deposited on Si substrates show the field emission current density of 1$\mu\textrm{A}/\textrm{cm}^2$ and 1mA/$\textrm{cm}^2$ have been measured at electric fields as low as 4.5V/$\mu\textrm{m}$ and 7.6V/$\mu\textrm{m}$, respectively. We also observed the similar emission characteristics from the defective diamond film deposited on Cr/Si substrate and could decrease the deposition temperature to $600^{\circ}C$.

• 한국진공학회지
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• 제5권1호
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• pp.54-61
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• 1996

Indium-tin oxide (ITO) films were deposited on the glass substrate by the reactive -ionized cluster beam deposition(ICBD) method. In the oxygen atmosphere, indium cluster formed through the nozzle is ionized by the electron bombardment and is accelerated to be deposited on the substrate. And tin is simultaneoulsy evaporated from the boron-nitride crucible. The chracteristics of films were examined by the X-ray photoelectron spectroscopy(XPS), glancing angle X-ray diffractrion(GXRD) and the electrical properties. were measured by 4-point-probe and Hall effect measurement system . From the XPS spectrum , it was found that indium and tin atoms combined with the oxygen to form oxide$(In_2O_3, SnO_2)$. In the case of films with high tin-concentration, the GXRD spectra show that the main $In_2O_3$ peak of (222) plane, but also sub peaks((440) peak etc.) and $SnO_2$ peaks were detected. From that results, itis concluded that the heavily dopped tin component (more than 14 at. %) disturbs to form $In_2O_3$(222) phase. Four-point-probe and Hall effect measurement show that, in the most desirable case, the transmittance of the films is more then 90% in visible range and its resistivity is $$\rho$=3.55 \times10^{-4}\Omega$cm and its mobility is $\mu$=42.8 $\textrm{cm}^2$/Vsec.