• Journal of the Korean institute of surface engineering
• /
• v.52 no.6
• /
• pp.310-315
• /
• 2019

The use of a silicon carbide (SiC)-based composite ceramic layer for the mold of a curved cover glass was demonstrated. The stress of SiC/VDR/graphite-based mold structure was evaluated via finite element analysis. The results revealed that the maximum tensile stress primarly occured at the edge region. Moreover, the stress can be reduced by employing a relatively thick SiC coating layer and, therefore, layers of various thicknesses were deposited by means of chemical vapor deposition. During growth of the layer, the orientation of the facets comprising the SiC grain became dominant with additional intense SiC(220) and SiC(004). However, the roughness of the SiC layer increased with increasing thickness of the layer and. Hence, the thickness of the SiC layer needs to be adjusted by values lower than the tolerance band of the curved cover glass mold.

• Journal of the Korean institute of surface engineering
• /
• v.53 no.5
• /
• pp.201-206
• /
• 2020

A SiOxCy(-H) thin film was synthesized by atmospheric pressure dielectric barrier discharge(APDBD), and a SiO₂-like layer was formed on the surface of the film by oxidation treatment using oxygen plasma. Hexamethylcyclotrisiloxane was used as a precursor for the SiOxCy(-H) synthesis, and He gas was used for stabilizing APDBD. Oxygen permeability was evaluated by forming an oxidized SiOxCy(-H) thin film on a PET film. When the single-layer oxidized SiOxCy(-H) film was coated on the PET, the oxygen gas permeability decreased by 46% compared with bare PET. In case of three-layer oxidized SiOxCy(-H) film, the oxygen gas permeability decreased by 73%. The oxygen permeability was affected by the thickness of the SiO₂-like layer formed by oxidation treatment rather than the thickness of the SiOxCy(-H) film. The excellent corrosion resistance was demonstrated by coating an oxidized SiOxCy(-H) thin film on the silver-coated aluminum PCB for light emitting diode (LED).

• Journal of the Korean institute of surface engineering
• /
• v.53 no.5
• /
• pp.213-218
• /
• 2020

Composite material of the graphene ball (GB) inserted graphene oxide (GO) sheet for a supercapacitor electrode was studied. Chemical vapor deposition (CVD) process used to make GBs on the silicon oxide nanoparticles. The GBs mixed into the GO sheets to make GOGB and reduced it to create a reduced GOGB(RGOGB) composite. The RGOGB composite electrode had a large surface area and improved electrochemical properties. Specific capacitance of the RGBGO composite electrode was higher over 20 times than a pure GO and GOGB electrode in cyclic voltammetry(CV) tests, and the Z' and Z" impedance measured by an electrochemical impedance spectrometry(EIS) also low. So, the RGBGO composite electrode would use effectively to expand a performance of supercapacitor.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.6
• /
• pp.580-585
• /
• 2004

Silicon dioxide (SiO$_2$) is widely used as a gate dielectric material for thin film transistors (TFT) and semiconductor devices. In this paper, SiO$_2$ films were grown by APCVD(Atmospheric Pressure chemical vapor deposition) at the high temperature. Experimental investigations were carried out as a function of $O_2$ gas flow ratios from 0 to 200 1pm. This article presents the SiO$_2$ gate dielectric studies in terms of deposition rate, refrative index, FT-IR, C-V for the gate dielectric layer of thin film transistor applications. We also study defect passivation technique for improvement interface or surface properties in thin films. Our passivation technique is Forming Gas Annealing treatment. FGA acts passivation of interface and surface impurity or defects in SiO$_2$ film. We used RTP system for FGA and gained results that reduced surface fixed charge and trap density of midgap value.

• Proceedings of the KIEE Conference
• /
• 2003.07c
• /
• pp.1592-1594
• /
• 2003

This paper presents the deposition and characterization of microcrystalline silicon(${\mu}c$-Si:H) films by HWCVD(Hot-wire Chemical Vapor Deposition) method at low substrate($300^{\circ}C$). The filament temperature, pressure and $SiH_4$ concentration were determined to be a critical parameter for the deposition of poly-Si films. Series A was deposited under the conditions of $1380^{\circ}C$(Tf), 100 mTorr and $2{\sim}10%\{SC:SiH_4/(SiH_4+H_2)\}$ for 60 min. Series B was deposited under the conditions of $1400{\sim}1450^{\circ}(T_f)$, 30 mTorr and $2{\sim}12%$(SC) for 60 min. The physical characteristics were measured by Raman and FTIR spectroscopy, dark and photoconductivity measurements under AM1.5 illumination.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.23 no.6
• /
• pp.656-662
• /
• 2015

In the present study, multi-layered Si DLC (Silicon Diamond-Like Carbon) coatings with HMDSO (Hexamethyldisiloxane) buffer layers are applied on SKD 11 substrates by PECVD (Plasma Enhanced Chemical Vapor Deposition) with different HMDSO gas flow rates, while the gas flow rate of $C_2H_2$ is fixed to enhance the electric resistivity of forming dies for electrically assisted forming. The HMDSO buffer layer is introduced to increase adhesion between the base metal and Si-DLC layers. The result of evaluation of electric resistivity and adhesion strength shows that the properties are affected by the flow rate of HMDSO, while the flow rate of 80 sccm results in the coating with the highest electric resistivity and adhesion strength among the selected flow rates.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.1
• /
• pp.99-102
• /
• 2002

Pinholes on the thermally grown oxide, which is called gate oxide, on silicon substrate under polysilicon layer are found and its mechanism is analyzed in this paper. The oxide under a polysilicon layer is broken during the plasma etching process of other polysilicon layer. Both polysilicon layers are separated with 0.8${\mu}{\textrm}{m}$ thick oxide deposited by CVD (Chemical Vapor Deposition). Since broken oxide points are found scattered around an arc occurrence point, it is assumed that an extremely high electric field generated near the arc occurrence point makes the gate oxide broken. 1'he arc occurrence point has been observed on the alignment key and is the mark of low yield. It is found that any arc occurrence can cause chips to fail by breaking the gate oxide, even if are occurrence points are found on scribeline.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.5
• /
• pp.689-695
• /
• 2002

Film compositions are needed in semiconductor manufacturing for such diverse application as production tool qualifications and process development. Surface and interface information is generally provided with Auger electron spectroscopy(AES). In this paper, WSix films were analyzed for structural, electrical, and compositional properties of tungsten silicide thin films produced by low pressure chemical vapor deposition as a function of temperature, DCS post flow, shower head life time, and the silicon to tungsten ratios have been investigated. We find that Si/W composition ratio is increased in the surface and interface of WSix thin films by the DCS post flow process and increasing deposition temperature, respectively. The results obtained in this study are also applicable to process control of WSix deposition for memory device fabrication.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.07a
• /
• pp.187-188
• /
• 2005

The characteristics of GaN epitaxial layers grown on silicon (111) substrates by metalorganic vapor phase epitaxy have been investigated. The only control of AlN thickness was found to decrease the stress sufficiently for avoiding crack formation in an overgrown thick ($2.6{\mu}m$) GaN layer. X-ray diffraction and photoluminescence measurements are used to determine the effect of AlN thickness on the strain in the subsequent GaN layers. Strong band edge photoluminescence of GaN on Si(111) was observed with a full width at half maximum of the bound exciton line as low as 17meV at 13K.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.190-190
• /
• 2010

Zinc oxide is the most attractive material due to the large direct band gap (3.37 eV), excellent chemical and thermal stability, and large exciton binding energy (60 meV). Recently, ZnO nanorods were used as the high efficient antireflection coating layer of solar cells based on silicon (Si). In this reports, we studied the effects of rapid thermal annealing (RTA) treatment on optical properties of ZnO nanorods. For fabrication of ZnO nanorods, there are many methods such as hydrothermal method, sol-gel method, and metal organic chemical vapor deposition method. Among of them, we used the conventional wet chemical method which is simple and low temperature growth. In order to synthesize the ZnO nanorods, the ZnO films were deposited on Si substrate by RF magnetron sputtering at room temperature and the samples were dipped to aqua solution containing the zinc nitrate and hexamethylentetramines (HMT). The synthesis process was achieved in keeping with temperature of $90-95^{\circ}C$ and under constant stirring. The morphology of ZnO nanorods on glass and Si was characterized by scanning electron microscopy. For the analysis of antireflection performance, the reflectance and transmittance were measured by spectrophotometer. And for analyzing the effects of RTA treatment on ZnO nanorods, crystalline properties were investigated by X-ray diffraction measurements and optical properties was estimated by photoluminescence spectra.