In this work, the etching characteristics of ZnO thin films were investigated using an inductively coupled plasma(ICP) of HBr/Ar/CHF3 gas mixtures. The plasma characteristics were analyzed by a quadrupole mass spectrometer (QMS) and double langmuir probe (DLP). The surface reaction of the ZnO thin films was investigated using X-ray photoelectron spectroscopy (XPS). The etch rate of ZnO was measured as a function of the CHF3 mixing ratio in the range of 0-15% in an HBr:Ar=5:2 plasma at a fixed gas pressure (6mTorr), input power (700 W), bias power (200 W) and total gas flow rate(50sccm). The etch rate of the ZnO films decreased with increasing CHF3 fraction due to the etch-blocking polymer layer formation.

Copper pillar tin bump (CPTB) was developed for high density chip interconnect technology. Copper pillar tin bumps that have 100μm pitch were introduced with fabrication process using a KM-1250 dry film photoresist (DFR), copper electroplating method and Sn electro-less plating method. Mechanical shear strength measurements were introduced to characterize the bonding process as a function of thermo-compression. Shear strength has maximum value with 330℃ and 500 N thermo-compression process. Through the simulation work, it was proved that when the copper pillar tin bump decreased in its size, it was largely affected by the copper oxidation.

In this study, HfAlO3 thin films using gate insulator of MOSFET were etched in inductively coupled plasma. The etch characteristics of the HfAlO3 thin films has been investigated by varying O2/BCl3/Ar gas mixing ratio, a RF power, a DC bias voltage and a process pressure. As the O2 concentration increases further, HfAlO3 was redeposited. As increasing RF power and DC bias voltage, etch rates of the HfAlO3 thin films increased. Whereas, as decreasing of the process pressure, etch rates of the HfAlO3 thin films increased. The chemical reaction on the surface of the etched the HfAlO3 thin films was investigated with X-ray photoelectron spectroscopy (XPS). These peaks moved a binding energy. This chemical shift indicates that there are chemical reactions between the HfAlO3 thin films and radicals and the resulting etch by-products remain on the surface.

(1-x)BaTiO3-x(Bi0.5Na0.5)TiO3 (0.01≤x≤0.10) ceramics were fabricated with muffled sintering by a modified synthesis process. Their positive temperature coefficient of resistivity (PTCR) characteristics were investigated systematically. All specimen showed a perovskite structure with a tetragonal symmetry. Both the lattice parameter of a and c axes were slightly decreased with increasing (Bi0.5Na0.5)TiO3 (BNT) content. Grain growth was achieved when the incorporated BNT was increased to 6 mol% and the inhibition of grain growth is considered to be due to the appearance of Ba vacancy (V"(Ba)) in the (1-x)BaTiO3-x(Bi0.5Na0.5)TiO3 (0.08≤x). With 4 mol% BNT addition, room temperature resistivity decreased to 48 Ω·㎝ and a resistivity jump (ρmax/ρmin) was as high as 1.1×10(4), respectively. Curie temperature was also increased to 171˚C with increasing BNT content.

In this study, we have investigated the effects of Mn dopant on the bulk trap levels and grain boundary characteristics of Bi2O3-based ZnO (ZB) varistor using admittance spectroscopy and dielectric functions (such as Z*, Y*, M*, ε*, and tanδ). Admittance spectra and dielectric functions show two bulk traps of Zn(i) (0.20 eV) and Vo (0.29~0.33 eV) in ZnO-Bi2O3-Mn3O4 (ZBM). The barrier of grain boundaries in ZBM could be electrochemically single type. However, its thermal stability was slightly disturbed by ambient oxygen because the apparent activation energy of grain boundaries was changed from 0.79 eV at lower temperature to 1.08 eV at higher temperature. The grain boundary capacitance Cgb was decreased slightly with temperature as 1.3~1.8 nF but resistance Rgb decreased exponentially. The relaxation time distribution can result from the heterogeneity of the barriers constituting the varistor. It is revealed that Mn dopant in ZB reduced the heterogeneity of the barrier in grain boundaries and stabilized the barrier against the ambient temperature.

In this study we aims to examine the effects of 0.5 mol% Cr2O3 addition on the reaction, microstructure development, resultant electrical properties, and especially the bulk trap and interface state levels of ZnO-Bi2O3-Sb2O3 (Sb/Bi=0.5, 1.0, and 2.0) systems (ZBS). The samples were prepared by conventional ceramic process, and characterized by XRD, density, SEM, I-V, impedance and modulus spectroscopy (IS & MS) measurement. The sintering and electrical properties of Cr-doped ZBS (ZBSCr) systems were controlled by Sb/Bi ratio. Pyrochlore (Zn2Bi3Sb3O14) was decomposed more than 100℃ lowered on heating in ZBS (Sb/Bi=1.0) by Cr doping. The densification of ZBSCr (Sb/Bi=0.5) system was retarded to 800℃ by unknown Bi-rich phase produced at 700℃. Pyrochlore on cooling was reproduced in all systems. And Zn7Sb2O12 spinel (α-polymorph) and δ-Bi(2)O(3) phase were formed by Cr doping. In ZBSCr, the varistor characteristics were not improved drastically (non-linear coefficient α=7~12) and independent on microstructure according to Sb/Bi ratio. Doping of Cr2O3 to ZBS seemed to form Zn(i) (0.16 eV) and Vo (0.33 eV) as dominant defects. From IS & MS, especially the grain boundaries of Sb/Bi=0.5 systems were divided into two types, i.e. sensitive to oxygen and thus electrically active one (1.1 eV) and electrically inactive intergranular one (0.95 eV) with temperature.

Nd and Ti co-doped bismuth ferrite (Bi1-xNdx)(Fe1-yTiy)O3 (x, y=0, 0.05, 0.1, 0.2) ceramics and thin films were synthesized through the conventional mixed-oxide process and pulsed laser deposition (PLD), respectively. Nd and Ti co-doping effect was examined with emphasis on how these impurities affect phase formation behavior as there could be the improvement in leakage current problems often associated with multiferroic BiFeO3 (BFO) thin films. The lattice constants of BFO ceramics decreased with Nd doping concentration up to 10mol%, while they further decreased with Nd and Ti co-doping to about 20%. BFO thin films obtained by the PLD process revealed random polycrystalline structure. Similar to bulk BFO ceramic, Nd and Ti co-doping effectively suppressed the formation of unwanted secondary phase and thus stabilized the perovskite phase in BFO thin films.

CuO doped WO3-SnO2 thick film gas sensors were fabricated by screen printing method on alumina substrates and heat-treated at 350℃ in air. The effects of mixing ratio of WO3 with SnO2 on the structural and morphological properties of WO3-SnO2 were investigated X-ray diffraction and Scanning Electron Microscope. The structural properties of the WO3-SnO2:CuO thick film by XRD showed that the monoclinic of WO3 and the tetragonal of SnO2 phase were mixed. Nano CuO was coated on the WO3-SnO2 surface and then the surface of WO3 was coated with SnO2 particles with 1~1.5 μm in diameters, as confirmed form the SEM image. The sensitivity of the WO3-SnO2:CuO sensor to 2000 ppm CO2 gas and 50 ppm H2S gas for the various ratio of WO3 and SnO2 was investigated. The 4 wt% CuO doped WO3-SnO2(75:25) tkick films showed the highest sensitivity to CO2 gas and H2S gas.

In this study, we investigated the optical, electrical, and structural properties of the IGZO(In2O3:Ga2O3:ZnO=1:9:90 wt.%) thin films prepared by RF-magnetron sputtering system under various substrate temperatures. All of the IGZO thin films shows an average transmittance of over the 80% in visible range. Most of all, deposited IGZO thin film at 100 ˚C substrate temperature have ZnO (002) of main growth peak and 17.02 nm of increased grains. And also IGZO thin film have low resistivity(1.35×10(-3) Ω·cm), high carrier concentration(6.62X10(20) cm-3) and mobility(80.1 cm2/Vsec). IGZO thin film have 2.08 mV at surface potential of electric force microscopy(EFM). We suggest that pre-annealing at 100 ˚C can be applied for improving optical, electrical and structural properties.

Single-phase Sr2FeMoO6 thin films were produced by RF magnetron sputtering for use as electrodes in integrated sensors and found to be good conductors at room temperature. The films were deposited from a powder-type sputtering target under various conditions, and were crystallized by annealing. Elimination of O2 gas during deposition, by the use of a solely Ar sputtering gas under a working pressure as low as possible, and vacuum annealing were important to promote the Sr2FeMoO6 phase. However, oxygen exclusion from sputtering and annealing was not enough to yield single-phase Sr2FeMoO6: hydrogen annealing was also required. Film production was optimized by varying the deposition parameters and hydrogen annealing conditions. The film had good electrical conduction, with a low resistivity of 1.6×10(-2)Ω·cm at room temperature.

The temperature of junction in LED affects the life time and performance. however, the measurement of junction temperature in module is very difficult. In this paper, to measure the junction temperature in LED module, optical and electrical properties is measured in single package in temperature from 25 [℃] to 85 [℃], and then junction temperature can is estimated in module with measuring the average voltage of single package. As results, the junction temperature of single package is measured the temperature of 61.2 [℃] in ambient temperature, also, the junction temperature of LED module is measured the temperature of 72.5 [℃] in ambient temperature.

For mass information transfer, the optical communication using optic fiber has been widely used. Especially, in the field of medical image, the large data is digitalized based on the standard image and it is used for telemedicine with this method. Therefore, to transfer the large amount of data fast and effectively POF (Plastic Optical Fiber) can be used and the development of optic connector for connection between POFs is very important. In this study, for stable optical coupling of POF optic fiber Ferrule and Sleeve were designed and produced by considering the bond stability and the insertion loss according to the physical contact and roughness profile was evaluated. As a result of examining the insertion loss by physical contact method of two optic fibers, it showed the loss was about 1.895dB. According to the results from studying the condition of grinding section for POF mass production, the mass production condition was established as POF profile roughness of 6nm and the loss of 0.2dB or lower by controlling the film size and time step by step.

In order to investigate the emission characteristics of the phosphorescent white organic light-emitting diodes (PHWOLEDs) according to various hole transport layers (HTLs), PHWOLEDs composed of HTLs whose structure are NPB/TCTA, NPB/mCP and NPB/TCTA/mCP, two emissive layers (EMLs) which emit two-wavelengths of light (blue and red), and electron transport layer were fabricated. The applied voltage, power efficiency, and external quantum efficiency at a current density of 1 ㎃/㎠for the fabricated PHWOLEDs were 7.5 V, 11.5 lm/W, and 15%, in case of NPB/mCP, 5 V, 14.8 lm/W, and 13.7%, in case of NPB/TCTA, and 5.5 V, 14.6 lm/W, and 15%, in case of NPB/TCTA/mCP in the hole transport layer, respectively. High emission efficiency can be obtained when the amount of hole injection from anode is balanced out by the amount of electron injection from the cathode to EML by using NPB/TCTA/mCP structured HTL.

In this study the (Alnico, Sm-Co) bonded magnets were fabricated by mixing the Sm-Co added alnico alloy powders with epoxy resin and binder, appropriately. Also, the hybrid ring magnets of (Alnico, Sm-Co)/Sr-ferrite were fabricated by coupling the Sr-ferrite composite layer with an (Alnico, Sm-Co) magnet. The magnetic properties of (Alnico, Sm-Co) ring magnets were varied with the amount of Sm-Co powders. The addition of Sm-Co powders increased a remanent induction(Br) and coercive force(BHC), while decreasing a surface flux density and repulsive distance. The surface flux density and repulsive distance for the (Alnico, Sm-Co) ring magnet increased with a magnetizing voltage up to about 160 V and reached an apparent saturation point. Also, the measurements of temperature and moisture characteristics showed that the surface flux densities of N-S poles and repulsive distance decreased a little within 4% after 10 days passed.

Recently, the demand of ceramic metal halide lamp has been expanded. Therefore, the lamp with high efficiency and long lifetime are increasing and the evaluation of reliability is needed. In this paper, the degradation phenomena of ceramic metal halide lamp was studied. The lamp was tested for 3000 on/off cycles with each cycle having a duration of 20 minutes on and 20 minutes off based on the accelerated aging experiment based on "Reliability Standards RS C 0085". As result, the corrosion of arc tube and leak was appeared from reaction between inner wall of PCA and chemical elements, and distortion of electrode was resulted from difference of thermal expansion between arc tube of PCA and electrode. Also, the efficiency of lamp was decreased by the change of inner pressure, operation temperature, and driving voltage from wall blackening.

In this study, magnesium (Mg), zinc (Zn) and aluminium (Al) as anode electrode and the solution of NaCl dissolved with 2~20 wt% as electrolytes were used for the metal-air cell. The open circuit voltage, short circuit current and I-V characteristics upon different kinds of anode electrode and electrolyte concentration were investigated. The open circuit voltage, initially about 1.45 V, rises to 1.6 V during the first 10 minutes indicating the necessity of an induction time to activate the catalyst on the air cathode. The short circuit current increases with an increased concentration of NaCl, causes an increase in the conductivity of the electrolyte solution, but the open circuit voltage did not under undergo influence of electrolyte. From NaCl 20 wt% electrolyte, the maximum output power of the magnesium electrode materials was measured with 177mW. It is found that the power characteristics of metal-air cell could be improved by using magnesium electrode materials in the NaCl electrolyte.