• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3367-3371
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• 2013

MgO nanorods were fabricated by the thermal evaporation of $Mg_3N_2$. The influence of ZnO sheathing and hydrogen plasma exposure on the photoluminescence (PL) of the MgO nanorods was studied. PL measurements of the ZnO-sheathed MgO nanorods showed two main emission bands: the near band edge emission band centered at ~380 nm and the deep level emission band centered at ~590 nm both of which are characteristic of ZnO. The near band edge emission from the ZnO-sheathed MgO nanorods was enhanced with increasing the ZnO shell layer thickness. The near band edge emission from the ZnO-sheathed MgO nanorods appeared to be enhanced further by hydrogen plasma irradiation. The underlying mechanisms for the enhancement of the NBE emission from the MgO nanorods by ZnO sheathing and hydrogen plasma exposure are discussed.

• Korean Journal of Materials Research
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• v.13 no.5
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• pp.303-308
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• 2003

Amorphous carbon nitride films deposited on Si(001) substrates by a plasma enhanced chemical vapor deposition (PECVD) technique using CH$_4$and $N_2$as reaction gases were thermally annealed at various temperatures under$ N_2$atmosphere, then their physical properties were investigated particularly as a function of annealing temperature. Above $600^{\circ}C$ a small amount of crystalline $\beta$-$C_3$$N_4$ phase evolves, while the film surface becomes very rough due to agglomeration of fine grains on the surface. As the annealing temperature increases, both the hardness and the $sp^3$ bonding nature are enhanced. In contrast to our expectation, higher annealing temperature results in a relatively higher friction mainly due to big increase in roughness at that temperature.

• Journal of the Korean Society of Safety
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• v.16 no.3
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• pp.41-44
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• 2001

The removal characteristics of nitrogen oxides (NOx) by the dielectric ($Al_2O_3$) packed-bed plasma reactor are experimentally investigated Reactor is packed with 5[mm] diameter $Al_2O_3$ beads, and was desisted to remove NOx at atmospheric pressures from the moving pollution source such as diesel automobile. The experiments were conducted for applied voltages from 5 to 10[kV], flue gas rate from 2 to 5[l/min] and frequency from 0.5 to 2[kHz]. The NOx removal efficiency significantly increasing with increasing applied voltage. Especially removal rate significantly increased with increasing frequency. However, in this experiment discharged poler n relatively high.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.6
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• pp.65-71
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• 2002

Characteristics of corona discharge of the different types of the plasma reactors which are cone-hole and cone-plate is investigated experimentally. The discharge starts at lower voltage for the cathode corona than the anode corona and spark occurs at higher voltage for the cathode corona. And the cathode corona makes more stable discharge than the anode corona. The effect of the base gas in corona discharge for different O$_2$/N$_2$ concentrations is related with the gas molecular weight. The discharge for the smaller molecular weight gas occurs easier than for the high molecular weight gas. The discharge current decreases with the increase of oxygen concentration and it increases more sharply for anode corona than for cathode corona as discharge voltage increases after corona onset voltage. NO-NO$_2$ conversion increases with the energy density of corona discharge and the addition of O$_2$ in a base N$_2$ gas.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.180-180
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• 2000

Plasma source ion implantation is a new doping technique for the formation of shallow junction with the merits of high dose rate, low-cost and minimal wafer charging damage. In plasma source ion implantation process, the wafer is placed directly in the plasma of the appropriate dopant ions. Negative pulse bias is applied to the wafer, causing the dopant ions to be accelerated toward the wafer and implanted below the surface. In this work, inductively couples plasma was generated by anodized Al antenna that was located inside the vacuum chamber. The outside wall of Al chamber was surrounded by Nd-Fe-B permanent magnets to confine the plasma and to enhance the uniformity. Before implantation, the wafer was pre-sputtered using DC bias of 300B in Ar plasma in order to eliminate the native oxide. After cleaning, B2H6 (5%)/H2 plasma and negative pulse bias of -1kV to 5 kV were used to form shallow p+/n junction at the boron dose of 1$\times$1015 to 5$\times$1016 #/cm2. The as-implanted samples were annealed at 90$0^{\circ}C$, 95$0^{\circ}C$ and 100$0^{\circ}C$during various annealing time with rapid thermal process. After annealing, the sheet resistance and the junction depth were measured with four point probe and secondary ion mass spectroscopy, respectively. The doping uniformity was also investigated. In addition, the electrical characteristics were measured for Schottky diode with a current-voltage meter.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.90-93
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• 2004

In this work, we have used different techniques for the surface passivation: conventional thermal oxidation (CTO), rapid thermal oxidation (RTO), and plasma-enhanced chemical vapour deposition (PECVD). The surface passivation qualities of eight different single and combined double layer have been investigated both on the phosphorus non-diffused p-type FZ silicon and on phosphorus diffused emitter of 100 ${\Omega}/Sq$ and 40 ${\Omega}/Sq$. In the single layer, silicon dioxide $(SiO_2)$ passivates good on the emitter while silicon nitride (SiN) passivates better than on the non-diffused surface. In the double layers, CTO/SiN1 passivates very well both on non-diffused surface on the emitter. However, RTO/SiN1 and RTO/SiN2 stacks are more suitable for surface passivation in solar cells caused by a relatively good passivation qualities and the low optical reflection. Applying these stacks in solar cells we achieved 18.5 % and 18.8 % on 0.5 ${\Omega}$ cm FZ-Si with planar and textured front surface, respectively. The excellent open circuit voltage $(V_{oc})$ of 675.6 mV is obtained the planar cell with RTO/SiN stack.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.407-408
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• 2000

유전체 장벽 방전 반응기 (Dielectric Barrier Discharge (DBD) Reactor)를 이용한 비열 플라즈마(Non-thermal plasma) 공정에서 NO 제거 특성을 실험적으로 연구하였다. 질소 분위기에서 전자에 의한 NO 의 제거는 $N_2$ + e $\longrightarrow$ N + N + e 반응에 의한 질소의 전자충돌해리 (electron-impact dissociation)와 이 반응에 의하여 생성된 질소원자에 의한 NO 의 환원반응 N + NO $\longrightarrow$ $N_2$ + O 으로 설명될 수 있으며, 이로 인하여 $O_2$ 나 $H_2O$ 의 첨가에 따른 부산물(O, $O_3$, OH 등)에 의한 산화반응이 주로 일어나는 경우 (XO + NO $\longrightarrow$ X + NO$_2$) 와는 달리 NO 제거에 소모된 에너지를 평가하기에 용이한 장점이 있다(Penetrante et al., 1995). (중략)

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.141-141
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• 2010

The effect of thermal anneal on the characteristics of structural properties and the enhancement of luminescence and photovoltaic (PV) characteristics of silicon-rich silicon-nitride films were investigated. By using an ultra high vacuum ion beam sputtering deposition, B-doped silicon-rich silicon-nitride (SRSN) thin films, with excess silicon content of 15 at. %, on P-doped (n-type) Si substrate was fabricated, sputtering a highly B doped Si wafer with a BN chip by N plasma. In order to examine the influence of thermal anneal, films were then annealed at different temperature up to $1100^{\circ}C$ under $N_2$ environment. Raman, X-ray diffraction, and X-ray photoemission spectroscopy did not show any reliable evidence of amorphous or crystalline Si clusters allowing us concluding that nearly no Si nano-cluster could be formed through the precipitation of excess Si from SRSN matrix during thermal anneal. Instead, results of Fourier transform infrared and X-ray photoemission spectroscopy clearly indicated that defective, amorphous Si-N matrix of films was changed to be well-ordered thanks to high temperature anneal. The measurement of spectral ellipsometry in UV-visible range was carried out and we found that the optical absorption edge of film was shifted to higher energy as the anneal temperature increased as the results of thermal anneal induced formation of $Si_3N_4$-like matrix. These are consistent with the observation that higher visible photoluminescence, which is likely due to the presence of Si-N bonds, from anneals at higher temperature. Based on these films, PV cells were fabricated by the formation of front/back metal electrodes. For all cells, typical I-V characteristic of p-n diode junction was observed. We also tried to measure PV properties using a solar-simulator and confirmed successful operation of PV devices. Carrier transport mechanism depending on anneal temperature and the implication of PV cells based on SRSN films were also discussed.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.2
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• pp.1-6
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• 2000

X-ray lithography mask with SiC membrane and Ta absorber patterns has been fabricated using ECR plasma CVD, d.c. magnetron sputtering, and ECR plasma etching. The stress of stoichiometric SiC film was adjusted by rapid thermal annealing under $N_2$, ambient. Adjusting the working pressure during sputtering process resulted in a near-zero residual stress, reasonable density, and smooth surface morphology of Ta film. Cl-based plasma showed a good etching characteristics of Ta, and two-step etching process was implemented to suppress microloading effect fur sub-quarter $\mu\textrm{m}$ patterning.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.211-211
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• 1999

Titanium nitride (TiN) thin films have useful properties including high hardness, good electrical conductivity, high melting point, and chemical inertness. The applications have included wear-resistant hard coatings on machine tools and bearings, decorative coating making use of the golden color, thermal control coatings for widows, and erosion resistant coatings for spacecraft plasma probes. For all these applications as feature sizes shrink and aspect ratios grow, the issue of good step coverage becomes increasingly important. It is therefore essential to manufacture conformal coatings of TiN. The growth of TiN thin films by chemical vapor deposition (CVD) is of great interest for achieving conformal deposition. The most widely used precursor for TiN is TiCl4 and NH3. However, chlorine impurity in the as-grown films and relatively high deposition temperature (>$600^{\circ}C$) are considered major drawbacks from actual device fabrication. To overcome these problems, recently, MOCVD processes including plasma assisted have been suggested. In this study, therefore, we have doposited Ti(C, N) thin films on Si(100) and D2 steel substrates in the temperature range of 150-30$0^{\circ}C$ using tetrakis diethylamido titanium (TDEAT) and titanium isopropoxide (TIP) by pulsed DC plamsa enhanced metal-organic chemical vapor deposition (PEMOCVD) method. Polycrystalline Ti(C, N) thin films were successfully grown on either D2 steel or Si(100) surfaces at temperature as low as 15$0^{\circ}C$. Compositions of the as-grown films were determined with XPS and RBS. From XPS analysis, thin films of Ti(C, N) with low oxygen concentration were obtained. RBS data were also confirmed the changes of stoichiometry and microhardness of our films. Radical formation and ionization behaviors in plasma are analyzed by optical emission spectroscopy (OES) at various pulsed bias and gases conditions. H2 and He+H2 gases are used as carrier gases to compare plasma parameter and the effect of N2 and NH3 gases as reactive gas is also evaluated in reduction of C content of the films. In this study, we fond that He and H2 mixture gas is very effective in enhancing ionization of radicals, especially N resulting is high hardness. The higher hardness of film is obtained to be ca. 1700 HK 0.01 but it depends on gas species and bias voltage. The proper process is evident for H and N2 gas atmosphere and bias voltage of 600V. However, NH3 gas highly reduces formation of CN radical, thereby decreasing C content of Ti(C, N) thin films in a great deal. Compared to PVD TiN films, the Ti(C, N) film grown by PEMOCVD has very good conformability; the step coverage exceeds 85% with an aspect ratio of more than 3.