Power semiconductor devices are widely used as high voltage applications to inverters and motor drivers, etc. The blocking voltage is one of the most important parameters for power semiconductor devices. And cause of junction curvature effects, the breakdown voltage of the device edge and device unit cells was found to be lower than the ``ideal`` breakdown voltage limited by the semi-infinite junction profile. In this paper, Propose the methods for field ring design by DOE (Design of Experimentation). So The field ring can be improve for breakdown voltage and optimization.

Power MOSFET is develop in power savings, high efficiency, small size, high reliability, fast switching, low noise. Power MOSFET can be used high-speed switching transistors devices. Recently attention to the motor and the application of various technologies. Power MOSFET is devices the voltage-driven approach switching devices are design to handle on large power, power supplies, converters, motor controllers. In this paper, design the 600 V Planar type, and design the trench type for realization of low on-resistance. For both structures, by comparing and analyzing the results of the simulation and characterization.

Due to the high etch rate and low fabrication cost, the wet etching of silicon using KOH etchant is widely used in MEMS fabrication area. However, anisotropic etch characteristic obstruct intuitional mask design and compensation structures are required for mask design level. Therefore, the accurate modeling for various types of silicon surface is essential for fabrication of three-dimensional MEMS structure. In this paper, we modeled KOH etch profile for MEMS based energy harvester using fuzzy logic. Modeling results are compared with experimental results and it is applied to design of compensation structure for MEMS based energy harvester. Through Fuzzy inference approaches, developed model showed good agreement with the experimental results with limited etch rate information.

Resistance-change Random Access Memory(ReRAM) memory, which utilizes electrochemical control of metal in thin films of solid electrolyte, shows great promise as a future solid state memory. The technology utilizes the electrochemical formation and removal of metallic pathways in thin films of solid electrolyte. Key attributes are low voltage and current operation, excellent scalability, and a simple fabrication sequence. In this work, we investigated the nature of thin films formed by photo doping of Ag+ ions into chalcogenide materials for use in solid electrolyte of Resistance-change RAM devices and switching characteristics according to field-effect.

Development of new efficient, high voltage switching devices with wide safe operating area and low on-state losses has received considerable attention in recent years. One of those structures with a very effective geometrical design is the trench gate Insulated Gate Bipolar Transistor(IGBT).power IGBT devices are optimized for high-voltage low-power design, decided to aim. Class 1,200 V NPT Planer IGBT, 1,200 V NPT Trench IGBT for class has been studied.

Gd(1-x)VO4:Eu(x)3+ red phosphors were synthesized with changing the concentration of Eu3+ ion by using a solid-state reaction method. The crystal structure, surface morphology, and photoluminescence and photoluminescence excitation properties of the red phosphors were measured by using X-ray diffractometer, field emission-scanning electron microscopy, and florescence spectrometer, respectively. The XRD results showed that the main peak of all the phosphor powders occurs at (200) plane. As for the photoluminescence properties, the maximum excitation spectrum occurred at 306 nm due to the charge transfer band from VO4(3-) to Eu3+ ions and the maximum emission spectrum was the red luminescence peaking at 619 nm when the concentration of Eu3+ ion was 0.10 mol.

In this study, [Li0.04(Na0.5K0.5)0.96](Nb0.86Ta0.10Sb0.04)O3 + xSrO (x=0, 0.0025, 0.005, 0.0075) ceramics were synthesized by the conventional mixed oxide method. The X-ray diffraction patterns demonstrated that ceramics possessed single perovskite structure. The SEM images indicate that microstructure can be obviously affected by a small amount of added SrO. The phase transition temperature tetragonal-cubic(T(c)) and orthorhombic -tetragonal(T(o-t)) shifts downward and upward with the increase of Sr addition, respectively. The excellent piezoelectric properties of d33=170[pC/N], k(p)=0.37, Q(m)=64.12, T(o-t)=153℃ and T(c)=370℃ were obtained from the 0.25 mol% Sr added ceramics sintered at 1,120℃ for 1 h.

TiO2 (Ti(1-x)Nb(x)O2, x= 0.04~0.06) transparent conducting oxide film was fabricated by RF magnetron sputtering process and their electrical, optical, stability properties were studied. When the Nb 4 at% sputtering target was used with RF power 120 W, pressure 8 mTorr, post-annealing temperature 60 0℃, the resistivity of TNO film was 4×10(-4) Ω-cm. The optical transmittance in the visible wavelength was ca. 86%. TNO films require heat treatment during or after the deposition process. When the film was deposited at room temperature and post-annealed at 600℃, the lowest resistivity was obtained. When the TNO film was exposed to high temperature and humidity, the resistivity of the film was rather decreased. The stability to temperature and humidity implies that the TNO film could be a appropriate candidate for In-free, ZnO-free transparent conducting oxide materials.

In this paper, we have studied on the optimal design of the optical compensation film for the TN-LCDs. To have wide viewing angle panels, several methods such as multi-domain method, optical path method, and phase compensation method have been proposed. Among these methods, this paper focused on the phase compensation method. In the phase compensation method, the phase retardation generated from the optical birefringence for the off-axis incident is compensated by using optical films with refractive anisotropy. To compensate the phase retardation of the TN-LCDs, we have proposed design concept for the biaxial optical films and analyzed the optical performance for the proposed structures. The calculation of the dynamic motion of the liquid crystals was based on the Ericksen-Leslie theory and the optical performance of the TN-LCD was calculated from the Extended Jones Matrix Method. From the results, we have confirmed that the optical characteristics of the TN-LCDs with the biaxial films have been improved considerably compared with the TN-LCDs compensated by the combination of the uniaxial films.

In this study, we have investigated the holographic grating formation on Ag-doped amorphous As-Ge-Se-S thin films. The dependence of diffraction efficiency as afunction of Ag layer thickness has been investigated in this amorphous chalcogenide films. Holographic gratings was formed using [P:P] polarized Diode Pumped Solid State laser (DPSS, 532.0 nm). The diffraction efficiency was obtained by +1st order intensity. The results were shown that the diffraction efficiency of Ag/AsGeSeS double layer thin films for the Ag thickness, the maximum grating diffraction efficiency using 60 nm Ag layer is 0.96%.

A rigorous electro-optical simulation and ray tracing for an electric field driven liquid crystal Fresnel lens was proposed to obtain design parameters of the electrode pattern of the Fresnel lens. The optimal design was carried out using Taguchi`s experimental method for 17.1"(368×229.5 mm) wide LCD panels with 9 views. For the calculation of the distribution of liquid crystal molecules and the optical transmission of the panel, finite difference method and extended Jones matrix method were used to deal effectively with highly nonlinear and complicated motional equations of the liquid crystal molecules and to obtain the oblique transmission characteristics of the LCD panel. As simulation results, the optimal lengths of the 3 electrodes of the Fresnel lens are 4.0 μm, 30 μm and 83 μm, respectively, and the locations of the second and third electrodes are 32.9-33.0 μm and 45.9-46.0 μm, respectively. The optimal applied voltage of the 3 electrodes are found to be 5.75 V, 7.80 V and 11.9 V, respectively.

We have developed new materials that lead to methyl meth acrylate monomer and styrene monomer to using polymerization method. The materials have a powder form and show liquid behavior. We call the "Electronic Bead". An our experiment, a positive-charged particle has TiO2, polymer and CCA(-), while a negative-charged particle consists of carbon black, polymer and CCA(+). The charged particles have electrical characteristic of white -10 uC/g and black 10 uC/g, respectively. Also, these particles have good fluidity by additive of nano-sized silica. Using these materials, we demonstrated prototype displays that have 320×320 array of pixels and 6-in-diagonal viewable image size, driven by passive-matrix addressing. The reflectivity shows about 30% even though our experiment is at the beginning point. Also, the panel has contrast ratio 6:1. We think there are many chances to improve reflectivity through modifying components of particle resin, mixture ratio of each particle, panel structure and so on.

This paper dealt with the fabrication of a partial discharge (PD) analyzer for insulation diagnosis of power facilities like transformers, cables and gas-insulated switchgears. An analytic algorithm for the phase (φ), the magnitude (q), and the pulse count (n) of PD pulse was designed and a time-frequency (TF) map algorithm was applied in the system to eliminate noises by analyzing the time and the frequency component of signals. All the algorithms were operated by a LabView graphical program. The detection circuit consists of a coupling capacitor, a detection impedance, and a low noise amplifier. A plane-plane and a point-plane electrode system were fabricated to simulate different types of insulation defects. In the experiment, we could easily understand the characteristics of PD pulses using the prototype PD analyzer.

Limiting thermal exposure time using rapid thermal processing(RTP) has emerged as promising simplified process for manufacturing of solar cell in a continuous way. This paper reports the simplification of co-firing using RTP. Actual temperature profile for co-firing after screen printing is a key issue for high-quality metal-semiconductor contact. The plateau time during the firing process were varied at 450℃ for 10~16 sec. Glass frit in Ag paste etch anti-reflection layer with plateau time. Glass frit in Ag paste is important for the Ag/Si contact formation and performances of crystalline Si solar cell. We achieved 17.14% efficiency with optimum conditions.

A layered planer SOFC module was designed from planar-type SOFC. It was prepared by multi-layered ceramic technology. To form the cathode and the anode in the layered structure, reliable channels should be made on the both side of electrolyte perpendicularly. However, monolithic SOFC using multi-layered ceramic technology hasn`t been studied another group, and the warpage of electrolyte in the channel, also, hasn`t been studied, when electrode is printed on the electrolyte. In this study, the channels are prepared with electrode printing, and their warpage are evaluated. In the case of YSZ without electrode, the warpages are nothing in the limit of measurement using optical microscope. The warpage of ``YSZ-NiO printed`` increases than that of ``NiO printed``, and also, the case of ``double electrode printed`` is similar to ``YSZ-NiO printed``. It is thought that, in the printed electrolyte, the warpage is related to the difference of the sintering behavior of each material.