• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.29-35
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• 1998

Substrates, SiC raw materials and graphite crucibles were purified for growing the high quality 6H-SiC single crystal ingot. Especially, XRD data of raw materials were analyzed before and after purification. We have grown 6H-SiC single crystal ingot up to 33 mm in diameter and 11 mm in length and SiC wafer for using the substrate and observing the internal defects was about 33 mm in diameter and 0.5 mm in thickness. Utilizing optical microscpe and Raman spectroscopy, internal defects density and crystallinity of the SiC wafer obtained by purification processes before crystal growth were measured. As a result, micropipe density and planar defect density were 100/$\textrm{cm}^2$ and 30/$\textrm{cm}^2$ respectively. Therefore, high quality 6H-SiC single crystal could be grown because internal defects density of 6H-SiC single crystal ingot was decreased by the purification processes before crystal growth.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.570-574
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• 2011

Large colorless single crystals of analcime with diameters up to 0.20 mm have been synthesized from gels with the composition of $3.00SiO_2$ : $1.50NaAlO_2$ : 8.02NaOH : $454H_2O$ : 5.00TEA. The fully $Na^+$-exchanged analcime have been prepared with aqueous 0.1 M NaCl (pH adjusted from 6 to 11 by dropwise addition of NaOH). The single-crystal structure of hydrated $|Na_{0.94}(H_2O)|[Si_{2.06}Al_{0.94}O_6]$-ANA per unit cell, a=13.703(3) ${\AA}$, has been determined by single-crystal X-ray diffraction technique in the orthorhombic space group Ibca at 294 K. The structure was refined using all intenties to the final error indices (using only the 1,446 reflections for which $F_o$ > $4{\sigma}(F_o))R_1/wR_2$ = 0.054/0.143. About 15 $Na^+$ ions are located at three nonequivalent positions and octahedrally coordinated. The chemical composition is $Na_{0.94}(H_2O)Si_{2.06}Al_{0.94}O_6$. The Si/Al ratio of synthetic analcime is 2.19 determined by the occupations of cations, 14.79, in the single-crystal determination work.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.477-480
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• 2002

Si-O-C(-H) thin film with a tow dielectric constant were deposited on a P-type Si(100) substrate by an inductively coupled plasma chemical vapor deposition (ICPCVD). Bis-trimethylsilymethane (BTMSM, H$_{9}$C$_3$-Si-CH$_2$-Si-C$_3$H$_{9}$) and oxygen gas were used as Precursor. Hybrid type Si-O-C(-H) thin films with organic material have been generated many voids after annealing. Consequently, the Si-O-C(-H) films can be made a low dielectric material by the effect of void. The surface characterization of Si-O-C(-H) thin films were performed by SEM(scanning electron microscope). The characteristic analysis of Si-O-C(-H) thin films were performed by X-ray photoelectron spectroscopy (XPS).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.7
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• pp.532-536
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• 2011

The silicon nitride films were prepared by chemical vapor deposition using inductively coupled plasma. During the deposition, the substrate was heated at $150^{\circ}C$ and power 1,000 W. To evolution low temperature manufacture, we have studied the role of source gases, $SiH_4$, $NH_3$, $N_2$, and $H_2$, to produce Si-N and N-H bond in a-SiNx:H film growth. $SiH_4$, $NH_3$, and $N_2$ flow rate fixed at 100, 10, and 10 sccm, $H_2$ flow rate varied from 0 to 10 sccm by small scale. To get the electrical characteristics, we makes MIM structure, and analysis surface bonding state. Experimental data show that Si-N and N-H bond is increased and hence electrical characteristics is showed 3 MV/cm breakdown-voltage, and leakage-current $10^{-7}\;A/cm^2$.

• Journal of the Korean institute of surface engineering
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• v.43 no.3
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• pp.127-131
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• 2010

Adhesion of DLC film is very significant property that exhibits wear resistance, chemical inertness and high hardness when being deposited to metal substrate. This study was considered that change adhesion of DLC film produced by Plasma Enhanced Chemical Vapor Deposition can be presented through inserting interlayer (Cr, Si-C:H). The thickness of interlayer was result of changing adhesion and residual stress. It was showed that the maximum 12 N of adhesion is on DLC film of Cr interlayer, and that a tendency is to be increased residual stress depend on the thickness. DLC film of Si-C:H interlayer represented 16 N of adhesion at $1{\mu}m$, whereas adhesion is decreased when the thickness is increased. For the interlayer at multi-layer, it was the best that adhesion of Cr/Si-C:H/DLC film was 33 N. Si-C:H interlayer at DLC film controled adhesion of the whole film. It was relaxed the internal stress of DLC film produced by inserting Cr, Si-C:H interlayer.

• Journal of the Korean Vacuum Society
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• v.16 no.4
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• pp.279-285
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• 2007

We have demonstrated structural evolution and optical properties of the Si-NWs on Si (111) substrates with synthesized nanoscale Au-Si islands by rapid thermal chemical vapor deposition(RTCVD). Au nano-islands (10-50nm in diameter) were employed as a liquid-droplet catalysis to grow Si-NWs via vapor-liquid-solid mechanism. Si-NWs were grown by a mixture gas of $SiH_4\;and\;H_2$ at pressures of $0.1{\sim}1.0$Torr and temperatures of $450{\sim}650^{\circ}C$. SEM measurements showed the formation of Si-NWs well-aligned vertically for Si (111) surfaces. The resulting NWs are 30-100nm in diameter and $0.4{\sim}12um$ in length depending on growth conditions. HR-TEM measurements indicated that Si-NWs are single crystals convered with about 3nm thick layers of amorphous oxide. In addition, optical properties of NWs were investigated by micro-Raman spectroscopy. The downshift and asymmetric broadening of the Si optical phonon peak with a shoulder at $480cm^{-1}$ were observed in Raman spectra of Si-NWs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.131-131
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• 2009

Silicon Carbide (SiC) is a material with a wide bandgap (3.26eV), a high critical electric field (~2.3MV/cm), a and a high bulk electron mobility ($\sim900cm^2/Vs$). These electronic properties allow high breakdown voltage, high-speed switching capability, and high temperature operation compared to Si devices. Although various SiC DMOSFET structures have been reported so far for optimizing performances, the effect of channel dimension on the switching performance of SiC DMOSFETs has not been extensively examined. This paper studies different channel dimensons ($L_{CH}$ : $0.5{\mu}m$, $1\;{\mu}m$, $1.5\;{\mu}m$) and their effect on the the device transient characteristics. The key design parameters for SiC DMOSFETs have been optimized and a physics-based two-dimensional (2-D) mixed device and circuit simulator by Silvaco Inc. has been used to understand the relationship. with the switching characteristics. To investigate transient characteristic of the device, mixed-mode simulation has been performed, where the solution of the basic transport equations for the 2-D device structures is directly embedded into the solution procedure for the circuit equations. We observe an increase in the turn-on and turn-off time with increasing the channel length. The switching time in 4H-SiC DMOSFETs have been found to be seriously affected by the various intrinsic parasitic components, such as gate-source capacitance and channel resistance. The intrinsic parasitic components relate to the delay time required for the carrier transit from source to drain. Therefore, improvement of switching speed in 4H-SiC DMOSFETs is essential to reduce the gate-source capacitance and channel resistance.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1475-1477
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• 2001

In odor to set high saturation magnetization and coercivity, it had need to orient axis of easy magnetization of CoCr-based thin film perpendicular direction(c-axis) to the substrate plane. It was known that crystalline orientation of CoCr-based thin film was improved by introducing underlayer like Ti, Ge. We prepared singlelayer and double layer with Si underlayer by Facing Targets Sputtering System. As a result, intensity and c-axis dispersion angle ${\Delta}{\theta}_{50}$ of singlelayer were improved with increasing film thickness. Also, it was found that CoCr/Si and CoCrTa/Si double layer showed good c-axis dispersion angle due to introducing Si.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.301-301
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• 2011

We present theoretical investigations of the self-assembled growth of one-dimensional (1D) molecular lines directed across the dimer rows on the H-terminated Si(001) surface [1]. Based on density-functional theory calculations, a new growth mechanism of the 1D acetylacetone line is proposed [2], which involves the radical chain reaction initiated at two dangling-bond sites on one side of two adjacent Si dimers. It is also enabled that, if an H-free Si dimer were employed as the initial reaction site, a 1D acetylacetone line can grow along the dimer row. Our findings represent the first insight into the growth of 1D molecular lines not only across but also along the dimer rows on the H-terminated Si(001) surface.

• Korean Journal of Materials Research
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• v.3 no.5
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• pp.459-465
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• 1993

By making the inter-metal PECVD $SiO_2$ as a Si rich oxide under the SOG, the hydrogen and water related diffusants could be captured a t SI dangling bonds. This gettering process was known to prevent the device characteristics degradations related to the H, $H_20$. The basic characteristics of Si rich oxide have been studied according to changing high/low frequency power and $SiH_4/N_2O$ gas flow ratio in PECVD. As increase in low frequency power, deposition rate decreased but K.I. and compressive stress increased. Decrease of the water peaks of FTIR spectra at the wave number range of 3300~3800$\textrm{cm}^{-1}$' also indicated that intensty the films were densified. As increase in SiH, gas flow rate, deposition rate, R.I. and etch rate increased while compressive stress decreased. F'TIK spectra showed that peak intensity corresponding to Si-0-Si stretching vibration decreased and shifted to the lower wave numbers. But AES showed that Si dangl~ng bonds were increased as a result of lower Si:O(l: 1.23) ratlo inthe Si rich oxide as compared to Si : O(1 : 1.98) ratio of usual oxide.