• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.11a
• /
• pp.387-390
• /
• 2002

SiC direct bonding technology is very attractive for both SiCOI(SiC-on-insulator) electric devices and SiC-MEMS(micro electro mechanical system) fields because of its application possibility in harsh environments. This paper presents pre-bonding techniques with variation of HF pre-treatment conditions for 2 inch SiC wafer direct bonding using PECVD(plasma enhanced chemical vapor deposition) oxide. The PECVD oxide was characterized by XPS(X-ray photoelectron spectrometer) and AFM(atomic force microscopy). The characteristics of the bonded sample were measured under different bonding conditions of HF concentration and an applied pressure. The bonding strength was evaluated by the tensile strength method. The bonded interface was analyzed by using IR camera and SEM(scanning electron microscope). Components existed in the interlayer were analyzed by using FT-IR(fourier transform infrared spectroscopy). The bonding strength was varied with HF pre-treatment conditions before the pre-bonding in the range of $5.3 kgf/cm^2$ to $15.5 kgf/cm^2$

• Journal of the Korean Chemical Society
• /
• v.36 no.4
• /
• pp.496-503
• /
• 1992

An ISFET urea sensor was fabricated by immobilizing the urease using photosensitive polymer, poly(vinyl alcohol)-SbQ on the H$^+$ sensing $Si_3$$N_4$ thin film of pH-ISFET. The sensor could determine the urea concentration in the range of 1∼50 mg/dl with fast response and good repeatability. For its application to clinical analysis, the interferences of the various materials which cause inhibition in urease catalytic reactions in blood was investigated. The results of the urea measurements in blood plasma using the ISFET urea sensor were compared with these of conventional spectrophotometric method.

• Mycobiology
• /
• v.35 no.1
• /
• pp.16-20
• /
• 2007

Hypolipidemic effect of biopolymers extracted from culture broth (CP), mycelia (MP), and fruiting bodies (FP) of Auricularia auricula-judae was investigated in dietary-induced hyperlipidemic rats. The experimental animals were administrated (100 mg/kg body weight) with different biopolymers, daily for 4 weeks. Hypolipidemic effects were achieved in all the experimental groups, however, FP was proved to be the most potent one. The administration of the FP reduced the plasma triglyceride, total cholesterol, low-density lipoprotein cholesterol, and atherogenic index by 24.3, 28.5, 36.4, and 40.9%, respectively, while increased the high-density lipoprotein cholesterol level (9.0%), when compared to the saline (control) administered group.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2016.11a
• /
• pp.103.1-103.1
• /
• 2016

플라즈마 코팅은 진공 및 진공에서 발생된 플라즈마 대기압 플라즈마를 이용하여 기판에 코팅하는 기술을 의미하는 것으로 최근 다양한 코팅 소스 및 물질계가 개발되면서 그 응용을 넓혀가고 있다. 플라즈마 코팅은 물리증착 및 화학증착에서 주로 이용하고 있는데 플라즈마를 이용하는 대표적인 기술로 스퍼터링과 음극아크증착, 플라즈마 화학증착 등이 있다. 스퍼터링은 기존의 마그네트론 스퍼터링에 비해 이온화율이 대폭 향상된 HIPIMS(High Power Impulse Magnetron Sputtering) 기술이 개발되면서 경질피막 제조의 신기술로 자리 잡고 있고 음극아크증착의 경우는 다양한 Filtered 아크소스가 개발되면서 후막 고경도 DLC(Diamond-like Carbon) 등 기존의 방법으로 달성할 수 없었던 코팅층의 제조가 가능하게 되었다. 최근 수명 및 물성이 크게 향상된 소재들이 다양하게 개발되었는데 이들 소재는 가공이 잘 되지 않는 난삭재가 대부분이어서 기존의 가공 Tool이 한계를 드러내고 있다. 이에 따라 난삭재 가공용 새로운 Tool에 대한 수요가 크게 증가하고 있는데 이에 대응하는 유력한 방법 중의 하나가 플라즈마를 이용한 경질코팅이다. 이렇듯 플라즈마 코팅은 난삭재가공용 Tool을 비롯하여 기계나 자동차 부품의 고경도, 저마찰 코팅, 기능성 코팅 등 다양한 분야에 응용을 확대하고 있다. 본 논문에서는 플라즈마 코팅의 최신 기술개발 동향과 그 응용에 대해 고찰하고자 한다.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.10
• /
• pp.2909-2912
• /
• 2010

Hydrogenated microcrystalline silicon (${\mu}c$-Si:H) thin film for solar cells is prepared by plasma-enhanced chemical vapor deposition and physical properties of the ${\mu}c$-Si:H p-layer has been investigated. With respect to stable efficiency, this film is expected to surpass the performance of conventional amorphous silicon based solar cells and very soon be a close competitor to other thin film photovoltaic materials. Silicon in various structural forms has a direct effect on the efficiency of solar cell devices with different electron mobility and photon conversion. A Raman microscope is adopted to study the degree of crystallinity of Si film by analyzing the integrated intensity peaks at 480, 510 and $520\;cm^{-1}$, which corresponds to the amorphous phase (a-Si:H), microcrystalline (${\mu}c$-Si:H) and large crystals (c-Si), respectively. The crystal volume fraction is calculated from the ratio of the crystalline and the amorphous phase. The results are compared with high-resolution transmission electron microscopy (HR-TEM) for the determination of crystallinity factor. Optical properties such as refractive index, extinction coefficient, and band gap are studied with reflectance spectra.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.687-690
• /
• 2009

It has been recently reported that nano-sized MgO single crystal powders emit ultraviolet by stimulation of electrons under vacuum condition. Therefore, in this study, nano-crystalline MgO powders were applied to a xenon plasma flat fluorescent lamp for LCD backlight to improve emission efficiency of the lamp by help of extra ultraviolet from nano-MgO. For comparison with nano-crystalline MgO powders, MgO nano-thin film was applied directly on phosphors inside a lamp panel through e-beam evaporation The luminance and efficiency of FFL with an addition of MgO nano-crystal powders on phosphors were improved by around 20%. Application of MgO thin film to phosphors worsened the emission characteristics of FFLs, even rather than FFL without MgO. The reason came from insufficient stimulation of phosphors by UV, crystallinity of MgO, and low secondary electron coefficient.

• Proceedings of the KIEE Conference
• /
• 2006.10a
• /
• pp.36-37
• /
• 2006

Both negative and positive substrate bias effects on the structural properties and field-emission characteristics are investigated. carbon nanotubes (CNTs) are grown on Ni catalysts employing an inductively-coupled plasma chemical vapor deposition (ICP-CVD) method. Characterization using various techniques, such as field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Auger spectroscopy (AES), and Raman spectroscopy, shows that the physical dimension as well as the crystal quality of CNTs grown can be changed and controlled by the application of substrate bias during CNT growth. It is for the first time observed that the prevailing growth mechanism of CNTs, which is either due to tip-driven growth or based-on-catalyst growth, may be influenced by substrate biasing. It is also seen that negative biasing would be more effectively role in the vertical-alignment of CNTs compared to positive biasing. However, the CNTs grown under the positively bias condition display much better electron emission capabilities than those grown under negative bias or without bias. The reasons for all the measured data regarding the structural properties of CNTs are discussed to confirm the correlation with the observed field-emissive properties.

• Proceedings of the KIEE Conference
• /
• 2006.10a
• /
• pp.105-106
• /
• 2006

The ferroelectric materials of the PZT, SBT attracted much attention for application to ferroelectric random access memory (FRAM) devices. Through the last decade, the lead zirconate titanate (PZT) is one of the most attractive perovskite-type materials for the ferroelectric products due to its higher remanant polarization and the ability to withstand higher coercive fields. FRAM has been currently receiving increasing attention for one of future memory devices due to its ideal memory properties such as non-volatility, high charge storage, and faster switching operations. In this study, we first applied the damascene process using chemical mechanical polishing (CMP) to the fabricate the $Pb_{1.1}(Zr_{0.52}Ti_{0.48})O_3$ thin film capacitor in order to solve the problems of plasma etching such as low etching profile and ion charging. The structural characteristics were compared with specimens before and after CMP process of PZT films. The scanning electron microscopy (SEM) analysis was performed to compare the morphology surface characteristics of $Pb_{1.1}(Zr_{0.52}Ti_{0.48})O_3$ capacitors. The densification by the vertical sidewall patterning and charging-free ferroelectric capacitor could be obtained by the damascene process without remarkable difference of the characteristics.

• Journal of the Semiconductor & Display Technology
• /
• v.10 no.1
• /
• pp.51-55
• /
• 2011

The surface passivation is one of the important methods that can improve the efficiency of solar cells and can be classified into two methods: wet-chemical passivation and film passivation. In this paper, chemical HF treatment were employed for the passivation of n-type silicon wafers and their effects were studied. To investigate film passivation effects, the silicon nitride films were also deposited by PECVD (plasma-enhanced chemical vapor deposition) on n-type silicon wafers treated with chemical HF. The minority carrier lifetime measurements were used for evaluation of the passivation characteristics in the all experiments steps. We confirmed that the minority carrier lifetime was improved with chemical HF treatment due to passivation effects by H-termination.

• The Journal of Korean Academy of Prosthodontics
• /
• v.27 no.1
• /
• pp.123-141
• /
• 1989

The purpose of this study was to investigate the tendency of color change of ceramic, and its mechanism un der the influence of Pd-Ag alloy. The specimens were made by firing porcelain on tile metal plates cast with Au-Pt alloy, Pd-Cu alloy and Pd-Ag alloy. In the case of Pd-Ag alloy, specimens were fired under three different conditions as follows, 1) without protection, 2) protection with ceramic metal conditioner, 3) protection with carbon block. For the specimens of element analysis, a barrier was constructed with platinum foil between metal plate and ceramic. Color change was measured with colorimeter and elemental changes in ceramic were calculated with DC argon plasma emission spectrophotometer. The results were as follows : 1. Color change of ceramic by Pd-Ag alloy was negligible in hue, but decreased in value and increased in chroma (yellow discoloration). 2. Color change of ceramic by Pd-Ag alloy was appeared through vapor transport mechanism. 3. As the protection method for the color change of ceramic by Pd-Ag alloy, application of ceramic metal conditioner was superior to utilization of carbon block.