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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Institute of Electrical and Electronic Material Engineers
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Journal DOI :
The Korean Institute of Electrical and Electronic Material Engineers
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Volume & Issues
Volume 14, Issue 12 - Dec 2001
Volume 14, Issue 11 - Nov 2001
Volume 14, Issue 10 - Oct 2001
Volume 14, Issue 9 - Sep 2001
Volume 14, Issue 8 - Aug 2001
Volume 14, Issue 7 - Jul 2001
Volume 14, Issue 6 - May 2001
Volume 14, Issue 5 - May 2001
Volume 14, Issue 4 - Apr 2001
Volume 14, Issue 3 - Mar 2001
Volume 14, Issue 2 - Feb 2001
Volume 14, Issue 1 - Jan 2001
Volume 12, Issue 4 - 00 2001
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Effect of Alternate Bias Stress on p-channel poly-Si TFT`s
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 869~873
The effects of alternate bias stress on p-channel poly-Si TFT\`s has been systematically investigated. We alternately applied positive and negative bias stress on p-channel poly-Si TFT\`s, device Performance(V
m/, leakage current, S-slope) are alternately appeared to be increasing and decreasing. It has been shown that device performance degrade under the negative bias stress while improve under the positive bias stress. This effects have been related to the hot carrier injection into the gate oxide rather than the generation of defect states within the poly-Si/SiO
interface under alternate bias stress.
Fabrication of Wafer Level Fine Pitch Solder Bump for Flip Chip Application
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 874~878
Solder bump was electroplated on wafer for flip chip application. The process is as follows. Ti/Cu were sputtered and thick PR was formed by several coating PR layer. Fine pitch vias were opened using via mask and then Cu stud and solder bump were electroplated. Finally solder bump was formed by reflow process. In this paper, we opened 40㎛ vias on 57㎛ thick PR layer and electroplated solder bump with 70㎛ height and 40㎛ diameter. After reflow process, we could form solder bump with 53㎛ height and 43㎛ diameter. In plating process, we improved the plating uniformity within 3% by using ring contact instead of conventional multi-point contact.
Structural and Dielectric Properties of (Sr.Ca)
-based Ceramics with the Substitution of Ca
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 879~884
In this paper, the structural and dielectric properties of (Sr
0.2) -based grain boundary layer ceramics were investigated by XRD, SEM and HP4194A. The ceramics were fabricated by the conventional mixed oxide method. The sintering temperature and time were 1420~152
and 4 hours, respectively. The average grain size and the lattice constant were decreased with increasing content of Ca. The average grain size was increased with increase of sintering temperature. The relative density of all specimens was 96~98%. The 2nd Phase formed by the thermal diffusion of CuO from the surface leads to very excellent dielectric properties, that is,
10%. The appropriate Ca content was under 15 ㏖%.s under 15 ㏖%.%.
Characteristics of Step-Down Transformer in PZT Piezoelectric Ceramics
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 885~891
Ring/dot-type step-down piezoelectric transformer was manufactured by using Pb[(Mn
ceramics, which have excellent high-power piezoelectric properties. The characteristics of step-down piezoelectric transformer as a function of load resistance at output terminal was examined. Voltage gain was greatly dependent on drive frequency and load resistance, and showed maximum voltage gain at the resonance frequency. The output voltage was linearly increased as the input voltage increased. Voltage gain of the step-down piezoelectric transformer with respect to input voltage was very stable when the load resistance was in the range of 50-500
Variation of Electrical Properties by E-field Induced Phase Transition in PZN-PT Crystals
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 892~897
Variations of dielectric and piezoelectric properties and associated phase transformation of <001> -oriented rhombohedral 0.92Pb (Zn
single crystals were investigated. The longitudinal strain level was found to abruptly increase at 15 kV/cm, corresponding to that where an induced phase appears within a multidomain matrix. Drastic decreases in the dielectric constant, transverse coupling, and transverse piezoelectric coefficient associated with the E-field induced phase were the result of increased crystal anisotropy in PZN-PT crystals. By contrast, the thickness coupling increased from 53 % at 0 kV/cm to 64 % at 45 kV/cm, also associated with this phase transition under the E-field. The measured dielectric and piezflelectric properties found for the induced phase state were nearly identical to those of <001> poled tetragonal (1-x)PZN-xPT (x>0.1) crystals. Based on these results, it is evident that the symmetry of induced phase is tetragonal.
Structural Characteristics of Multilayer Piezoelectric Transformer According to Designs of Internal Electrode
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 898~903
In this study, we investigated amounts, distributions and sizes of pores of multilayer piezoelectric transformer, and predicted heat emission property and electrical characteristics according to designs of internal electrode. Forming densities of device having MLC, fingered and full filled internal electrode structure were 4.73 g/㎤, 4.80 g/㎤, 4.82 g/㎤ and forming porosities were 17.3737%, 13.1475%, 12.6121%, respectively. And sintered densities of MLC structured, fingered and full filled devices were 7.76 g/㎤, 7.75 g/㎤, 7.84 g/㎤ and sintered porosities were 4.0967%, 2.7132%, 2.5317%, respectively. Therefore, we concluded that fingered and full fi1led internal electrode devices, expecially, fingered internal electrode devices had cost-effective effect and maximum poling effect due to higher sintered density and lower porosity than MLC structured device. Also we can predict that they have an effect on good heat emission and high output properties of multilayer piezoelectric transformer.
Synthesis and Piezoelectric Properties of PZT Ceramics will Improved Process
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 904~911
High-density lead zirconate titanate(Pb(Zr
, PZT) ceramics were fabricated by a new milling-precipitation(MP) process improved from the conventional solid state process. This process was progressed by a milling impregnation through mixing ZrO
powders with lead nitrate(Pb(NO
) water solution in zirconia ball media, and then milling precipitation was induced from precipitation of PbC
by adding ammonium of oxalate monohydrate((NH
O) as a precipitant. As a result of this process, single-phase perovskite structure was formed at the calcination temperature of 750
powders. In addition, the highest density at the sintering temperature of 1100
was obtained, because of the highly sinterable PZT Powders ground through the re-milling process. Piezoelectric and dielectric properties of sintered sample were improved by MP process.
A Basic Study on the Low Drift Flux Meter by Using a Peltier Device
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 912~916
Fluxmeter is a measuring instrument the magnetic flux intensity by means of an integration of the voltage induced to a search coil to unit time. It also is required to a precise integrator since the voltage induced to a search coil has a differential value of the flux
to unit time. In this study, a bias current which is a main problem of the integrator in a drift troublesome depending on the temperature of a FET is investigated. We have confirmed that the temperature dependence of both the bias current of a integrator using the FET and the reversal saturated current of the minor carrier in a P-N junction of a semiconductor were the same. The property of a commercial integrator goes rapidly down with increasing temperature. The bias current of a FET is increased twice as much with 10
increment. As a result, the low drift integrator could be developed by setting the lower temperature up with a pottier device.
Liquid Crystal Aligning Capabilities Using the in-situ Photo-alignment Method on Photo-crosslinkable Polymer Surface
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 917~921
Aligning capabilities for nematic liquid crystal (NLC) using a in-situ photodimerization method on various Photo-crosslinkable Polyimide (Pl) based polymer and blending photopolymer surfaces were investigated. High pretilt angle of the NLC can be measured by obliquely polarized UV exposure on a photo-crosslinkable polyimide based polymer surface containing biphenyl (BP), decyl (de), and cholesteryl (chol) group, respectively. However, the low pretilt angle of the NLC was measured by obliquely polarized UV exposure on the blending photopolymer (Pl and cinnamate materials) surfaces. Consequently, the pretilt angle of the NLC generated on the photo-crosslinkable polyimide based polymer surfaces using the in-situ photodimerization method was higher than that of the blending photopolymers.
The Study on the Improved Quantum Efficiency of the PVK:Bu-PBD:C6 Single Layer Green Light Emitting Devices
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 922~927
Single-layer green ELs was fabricated with using molecularly-dispersed Bu-PBD into poly-N-vinylcarbazole(PVK) which has low operating voltage and high quantum efficiency. A EL cell structure of glass substrate/indium-tin-oxide/PVK:Bu-PBD:C6(∼ 100nm)/Ca(20nm)/Al(20nm) was employed with variable doping concentration. The keys to obtain high quantum efficiency was excellent film forming capability of molecularly dispersed into PVK and appropriate combination of cathode for avoiding exciplex. We obtained the turn-on voltage of 4.2V and quantum efficiency of 0.52% at 0.lmol% of C6 concentration which has been improved about a factor of 50 in comparison with the undoped cell. The PL peak wavelengths wouldn\`t be turned by changing the concentration of the C6 dopant. Green EL emission peak and FWHM were 520nm and 70nm respectively. PL emission peak was obtained at 495nm.
Development of New Laser Material for High Power and High Efficiency
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 928~933
Perdeuterated hexaflouroacetylacetonato-ytterbium [Yb(SOL-D)
] complexes are synthesized by the keto-enol tautomerism reaction of Yb(SOL-H)
in order to reduce the radiationless transition to the ligands for the high power solid state laser material. The luminescence properties of Yb(SOL-D)
complex are measured in the following anhydrous deuterated organic solvents ; Methanol-d
. The Luminescence intensity, lifetime and quantum efficiency in DMSO-d
are superior to those in other deuterated solvents. It is suggested that the anhydrous DMSO-d
might be the most appropriate solvent for the laser material of Yb(SOL-D)
Tunneling Magnetoresistance in Si/
/Co Thin Films
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 934~940
Magnetic properties were investigated for Si/SiO
(t)/Co(200 ) junction related with the parameters of
layer was formed by depositing a 5~40 thick Al layer, followed by a 90~120s RF plasma oxidation in an
atmosphere. Magnetoresistance was not observed for tunnel junction with 5~10 thick Al layer, but magnetoresistance was observed large for tunnel junction with 15~40 thick Al layer. Oxidation time did not largely influence magnetoresistance. Tunnel magnetoresistance effect depended on magnetization behavior of two ferromagnetic layers. Tunneling junction was confirmed through nonlinear I-V curve. In this work, tunneling magnetoresistance(TMR) up to 30 % was observed. This apparent TMR is an artifact of the nonuniform current flow over the junction in the cross geometry of the electrodes.
A Study on Dielectric Strength and Insulation Properly of PDMS
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 941~946
The fundamental study on HTV silicone for insulation material has been performed. In order to estimate the chemical behavior of siloxane under high voltage, H-NMR, GPC and vinyl contents measurement were used. As an experimental results, after high voltage stress, the molecular weight of siloxane are increased, the vinyl contents of siloxane are decreased. The dielectric strength of vinyl group containing siloxane was lower than only methyl containing siloxane.
A Study for the SAW Convolver Using Parabolic Horn Waveguide
Journal of the Korean Institute of Electrical and Electronic Material Engineers, volume 14, issue 11, 2001, Pages 947~952
In this paper, a wideband SAW convolver using a parabolic horn waveguide was designed and its characteristics were investigated. The convolver was made with parabolic horn waveguide at compression ratio 9:1 for reducing propagation loss and for improving convolution efficiency between two input IDTs of center frequency 193.78 ㎒. The SAW convolver utilizing acoustic nonlinearities of piezoelectric material demonstrated that it can provide large S/N ratio and can be use for programmable matched filter(PMF) in spread spectrum communication system.