• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.4
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• pp.330-335
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• 2003

This paper reports the optimum structure of the vacuum packaged Porous poly-silicon Nano-Structured (PNS) emitter. The PNS layer was obtained by electrochemical etching process into polycrystalline silicon layer in a process controlled to anodizing condition. Current-voltage studies were carried out to optimize process condition of electron emission properties as a function of anodizing condition and top electrode thickness. Also, we measured in advance the electron emission properties as a function of substrate temperature because the vacuum packaged process was performed under the condition of high temperature ambient (430$^{\circ}C$). Auger Electron Spectrometer (AES) studies shows that Au as a top-electrode was diffused to PNS layer during temperature experiments. Thus, we optimized the thickness of top-electrode in order to make the vacuum package PNS emitter. As a result, the vacuum Packaged PNS emitter was successfully emitted by optimizing process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.354-357
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• 2002

Thermally grown gate oxide on 4H-SiC wafer was investigated. The oxide layers were grown at l150$^{\circ}C$ varying the carrier gas and post activation annealing conditions. Capacitance-Voltage(C-V) characteristic curves were obtained and compared using various gate electrode such as Al, Ni and poly-Si. The interface trap density can be reduced by using post oxidation annealing process in Ar atmosphere. All of the samples which were not performed a post oxidation annealing process show negative oxide effective charge. The negative oxide effective charges may come from oxygen radical. After the post oxidation annealing, the oxygen radicals fixed and the effective oxide charge become positive. The effective oxide charge is negative even in the annealed sample when we use poly silicon gate. Poly silicon layer was dope by POCl$_3$ process. The oxide layer may be affected by P ions in poly silicon layer due to the high temperature of the POCl$_3$ doping process.

• Journal of Electrochemical Science and Technology
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• v.11 no.4
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• pp.392-398
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• 2020

Producing solar grade silicon using an inexpensive method is a key factor in lowering silicon solar cell costs; the direct electrochemical reduction of SiO₂ in molten salt is one of the more promising candidates for manufacturing this silicon. In this study, SiO₂ granules were electrochemically reduced in molten CaCl₂ (850℃) using Ag-Si eutectic droplets that catalyze electrochemical reduction and purify the Si product. When Ag is used as the working electrode, the Ag-Si eutectic mixture is formed naturally during SiO₂ reduction. However, since the Ag-Si eutectic droplets are liquid at 850℃, they are easily lost during the reduction process. To minimize the loss of liquid Ag-Si eutectic droplets, a cylindrical graphite container working electrode was introduced and Ag was added separately to the working electrode along with the SiO₂ granules. The graphite container working electrode successfully prevented the loss of the Ag-Si eutectic droplets during reduction. As a result, the Ag-Si eutectic droplets acted as stable catalysts for the electrochemical reduction of SiO₂, thereby producing one-dimensional Si rods through a mechanism similar to that of vapor-liquid-solid growth.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1085-1088
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• 2003

In this work, we fabricated a gas-sensing device based on porous silicon(PS), and its I-V and C-V properties were investigated for sensing alcohol vapor. The structure of the sensor consists of thin Au/Oxidized porous silicon/porous silicon/Silicon/Al, where the silicon substrate is etched anisotropically to be prepared into a membrane shape. As the result, I-V curves showed typical tunneling property, and C-V curves were shaped like those of a MIS (metal-insulator- semiconductor) capacitor, where the capacitance in accumulation was increased with alcohol vapor concentration.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.297-299
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• 2003

In this paper, we present the fabrication of copper electrode array and test of electrochemical discharge machining for the fabrication of microholes on Borofloat33 glass. Copper electrode array is fabricated by the bonding of silicon upper substrate and lower substrate and copper electroplate. The silicon upper electrode having microholes fabricated by ICP-RIE is the mold of copper electroplate. The lower substrate is used as the seed layer for copper electroplate after Au - Au thermocompression bonding with the upper substrate.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1297-1299
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• 1998

LB layers of L-$\alpha$-DLPC deposited by LB method were deposited onto n-type silicon wafer as Z-type film. Films made up of 8, 16 layers of lipid with long alkyl chain and the thickness of monolayer and multilayers was determined by ellipsometry. It was deposited Ag and Al onto LB layers and silicon wafer for electrode and small electrode exhibit high capacitance and low leakage current. The C-V curves of the MLS capacitor shows very high saturation value of capacitance. And cross-sectional SEM image of MLS capacitor indicated the presence of pore with Al electrode and we found that the Ag is good for electrode metal.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.8
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• pp.628-636
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• 1998

LB layers L-$\alpha$-DLPC deposited by LB method were deposited onto n-type silicon wafer as Z-type film. Films made up of 8, 16 layers of lipid with long alkyl chain and the thickness of monolayer and multiayers was determined by ellipsometry. Ut was deposited Ag and Al onto LB layers and silicon wafer for electrode and small electrode exhibit high capacitiance and low lekage current. The C-V curves of the MLS capacitor shows very high saturation value of capacitance. And cross-sectional SEM image of MLD capacitor indicated the presence of pore with Al electrode and we found that the Ag is good for electrode metal.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.12
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• pp.1115-1121
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• 1998

MLS capacitor with lipid ultra thin films were deposited by Langmuir-Blodgett (LB) method on the silicon wafer. The current versus voltage and capacitance versus voltage relationships are depend on the applied voltage, electrode area and electrode materials. LB films deposited were made of L-$\alhpa$-DLPC, the 1 layer’s thickness of 35${\AA}$ was measured by ellipsometer. And MLS capacitor with different electrode materials, the work function of these materials was investigated to increase the leakage current. The result indicated the lower leakage current and very high saturation value of capacitance was reached within 700-800 pF when the two electrode was Ag. And $\varepsilon$1, $\varepsilon$2 versus photon energy showed good film formation.

• Journal of the Korean Electrochemical Society
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• v.3 no.1
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• pp.39-43
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• 2000

The light emitting diode (LED) was fabricated from n-type porous silicon. We investigated both the current-voltage characteristics of the LED with various electrode materials and changes of electroluminescence with applied current density. Also we probed changes in electroluminescence as a function of operation time at a given current. In order to Improve the contact area between the electrode material and porous silicon layer, we deposited indium on porous silicon layer by electroplating and investigated the electric characteristics of the LED and changes of electroluminescence.

• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.320-326
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• 2018

In this study, Graphite/Silicon/Carbon (G/Si/C) composites were synthesized to improve the electrochemical properties of Graphite as an anode material of lithium ion battery. The prepared G/Si/C composites were analyzed by XRD, TGA and SEM. Also the electrochemical performances of G/Si/C composites as the anode were performed by constant current charge/discharge, rate performance, cyclic voltammetry and impedance tests in the electrolyte of $LiPF_6$ dissolved inorganic solvents (EC:DMC:EMC=1:1:1 vol%). Lithium ion battery using G/Si/C electrode showed better characteristics than graphite electrode. It was confirmed that as the silicon content increased, the capacity increased but the capacity retention ratio decreased. Also, it was shown that both the capacity and the rate performances were improved when using the Silicon (${\leq}25{\mu}m$). It is found that in the case of 10 wt% of Silicon (${\leq}25{\mu}m$), G/Si/C composites have the initial discharge capacity of 495 mAh/g, the capacity retention ratio of 89% and the retention rate capability of 80% in 2 C/0.1 C.