• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.97-101
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• 1995

GaN films were prepared on Si(111) substrates by hydride vapor phase epitaxy (HVPE) on HCl-NH$_3$-N$_2$gas system. Effects of HCl gas flow rate on the film investigate under deposition conditions of flow time of 10min, 20min, 30min. The deposition rate increased with increasing HCl gas flow rate in the range of 10cc/min to 40cc/min and deposition time. Strung (00.2) oriented GaN film was obtained at a lower HCl flow rate and improved of the surface morphology.

• Korean Journal of Materials Research
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• v.12 no.3
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• pp.190-194
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• 2002

InN/GaN multi-layers were grown by metalorganic chemical vapor deposition(MOCVD) in order to get the appropriate structure for an high power blue-green light emitting diode(LED), and effects of growth conditions (growth temperature, pressure, and $trimethylindium(TMIn)-NH_3-N_2\; flow\; rare)$ on the integrated photoluminescence (PL) intensity and PL peak energy in InN/GaN multi-layers were investigated. The optimized growth conditions with the highest integrated PL intensity for InN/GaN multi-layers were obtained: the growth temperature at $780^{\circ}C$, the growth pressure at 325 Torr, the TMIn flow rate with 150 $m\ell$/min, the $NH_3$flow rate with 3.2 ι/min, and $N_2$ flow rate with 2 ι/min.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.458-458
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• 2010

The process window for the etch selectivity of silicon nitride ($Si_3N_4$) layers to extreme ultra-violet (EUV) resist and variation of line edge roughness (LER) of EUV resist were investigated durin getching of $Si_3N_4$/EUV resist structure in a dual-frequency superimposed capacitive coupled plasma (DFS-CCP) etcher by varying the process parameters, such as the $CH_2F_2$ and $N_2$ gas flow rate in $CH_2F_2/N_2$/Ar plasma. The $CH_2F_2$ and $N_2$ flow rate was found to play a critical role in determining the process window for infinite etch selectivity of $Si_3N_4$/EUV resist, due to disproportionate changes in the degree of polymerization on $Si_3N_4$ and EUV resist surfaces. The preferential chemical reaction between hydrogen and carbon in the hydrofluorocarbon ($CH_xF_y$) polymer layer and the nitrogen and oxygen on the $Si_3N_4$, presumably leading to the formation of HCN, CO, and $CO_2$ etch by-products, results in a smaller steady-state hydrofluorocarbon thickness on $Si_3N_4$ and, in turn, in continuous $Si_3N_4$ etching due to enhanced $SiF_4$ formation, while the $CH_xF_y$ layer is deposited on the EUV resist surface. Also critical dimension (and line edge roughness) tend to decrease with increasing $N_2$ flow rate due to decreased degree of polymerization.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.210-210
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• 2011

The effects of CH2F2 and N2 gas flow rates on the etch selectivity of silicon nitride (Si3N4) layers to extreme ultra-violet (EUV) resist and the variation of the line edge roughness (LER) of the EUV resist and Si3N4 pattern were investigated during etching of a Si3N4/EUV resist structure in dual-frequency superimposed CH2F2/N2/Ar capacitive coupled plasmas (DFS-CCP). The flow rates of CH2F2 and N2 gases played a critical role in determining the process window for ultra-high etch selectivity of Si3N4/EUV resist due to disproportionate changes in the degree of polymerization on the Si3N4 and EUV resist surfaces. Increasing the CH2F2 flow rate resulted in a smaller steady state CHxFy thickness on the Si3N4 and, in turn, enhanced the Si3N4 etch rate due to enhanced SiF4 formation, while a CHxFy layer was deposited on the EUV resist surface protecting the resist under certain N2 flow conditions. The LER values of the etched resist tended to increase at higher CH2F2 flow rates compared to the lower CH2F2 flow rates that resulted from the increased degree of polymerization.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.78-79
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• 2007

In this study, chemical dry characteristics of silicon nitride layers were investigated in the $F_2/N_2/Ar$ remote plasma. A toroidal-type remote plasma source was used for the generation of remote plasmas. The effects of additive $N_2$ gas on the etch rates of various silicon nitride layers deposited using different deposition techniques and precursors were investigated by varying the various process parameters, such as the $F_2$ flow rate, the addition $N_2$ flow rate and the substrate temperature. The etch rates of the various silicon nitride layers at the room temperature were initially increased and then decreased with the $N_2$ flow increased, which indicates an existence of the maximum etch rates. The etch rates of the silicon oxide layers were also significantly increased with the substrate temperature increased. In the present experiments the $F_2$ gas flow, addition $N_2$ flow rate and the substrate temperature were found to be the critical parameters in determining the etch rate of the silicon nitride layers

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.926-929
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• 1999

In this paper, we have studied the role of sources gases, SiH$_4$, NH$_3$ and $N_2$, to produce Si-N and Si-H bond in PECVD. The correlations of a deposition rate, a refractive index and a permitivity were investigated with the NH$_3$ flow rate of 6, 9 and 12 sccm, and SiH$_4$ flow rate of 20, 30 and 40 sccm, and substrate temperature of 150, 250 and 35$0^{\circ}C$. But the $N_2$ flow rate and chamber pressure were fixed at 55 sccm and 700mTorr. And then MIM capacitors were fabricated and tested for MMIC applications.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.7
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• pp.662-666
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• 2005

Silicon nitride $(SiN_x)$ film is a promising material for anti-reflection coating and passivation of multicrystalline silicon (me-Si) solar cells. In this work, a plasma-enhanced chemical vapor deposition (PECVD) system with batch-type reactor tube was used to prepare highly robust $SiN_x$ films for screen-printed mc-Si solar cells. The Gas flow ratio, $R=[SiH_4]/[NH_3]$, in a mixture of silane and ammonia was varied in the range of 0.0910.235 while maintaining the total flow rate of the process gases to 4,200 sccm. The refractive index of the $SiN_x$ film deposited with a gas flow ratio of 0.091 was measured to be 2.03 and increased to 2.37 as the gas flow ratio increased to 0.235. The highest efficiency of the cell was $14.99\%$ when the flow rate of $SiH_4$ was 350 sccm (R=0.091). Generally, we observed that the efficiency of the mc-Si solar cell decreased with increasing R. From the analysis of the reflectance and the quantum efficiency of the cell, the decrease in the efficiency was shown to originate mainly from an increase in the surface reflectance for a high flow rate of $SiH_4$ during the deposition of $SiN_x$ films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.3
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• pp.235-238
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• 2009

This paper describes the mechanical properties of poly (Polycrystalline) 3C-SiC thin films with $N_2$ in-situ doping. In this work, the poly 3C-SiC film was deposited by APCVD (Atmospheric Pressure Chemical Vapor Deposition) method using single-precursor HMDS (Hexamethyildisilane: $Si_2(CH_3)_6)$ at $1200^{\circ}C$. The mechanical properties of doped poly 3C-SiC thin films were measured by nono-indentation according to the various $N_2$ flow rate. In the case of 0 sccm $N_2$ flow rate, Young's Modulus and hardness were obtained as 285 GPa and 35 GPa, respectively. Young's Modulus and hardness were decreased according to increase of $N_2$ flow rate. The crystallinity and surface roughness was also measured by XRD (X-Ray Diffraction) and AFM (Atomic Force Microscopy), respectively.

• Journal of the Korean Magnetics Society
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• v.16 no.5
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• pp.240-244
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• 2006

In this paper, magnetic properties and annealing behavior of spin valve structures using Mo(MoN) layers as underlayers were studied varying the thickness of the underlayers. The spin valve structure was consisted of Si substrate/$SiO_2(2,000{\AA})/Mo(MoN)(t{\AA})/NiFe(21\;{\AA})/CoFe(28\;{\AA})/Cu(22\;{\AA})/CoFe(18\;{\AA})/IrMn(65\;{\AA})/Ta(25\;{\AA})$. Also, MoN films were deposited on Si substrates and their thermal annealing behavior was analyzed. The resistivity of the MoN film increased as the $N_2$ gas flow rate was increased. After annealing at $600^{\circ}C$, XRD results did not show peaks of silicides. XPS results indicated MoN film deposited with 5 sccm of $N_2$ gas flow rate was more stable than the film deposited with 1 sccm of $N_2$ gas flow rate. The variations of MR ratio and magnetic exchange coupling fold were small for the spin valve structures using Mo(MoN) underlayers up to thickness of45 ${\AA}$. MR ratio of spin valves using MoN underlayers deposited with various $N_2$ gas flow rate was about 7.0% at RT and increased to about 7.5% after annealing at $220^{\circ}C$. Upon annealing at $300^{\circ}C$, the MR ratio decreased to about 3.5%. Variation of $N_2$ gas flow rate up to 5 sccm did not change the MR ratio and $H_{ex}$ appreciably.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.117-119
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• 2017

The multi-stage catalytic igniter for hybrid rocket auto ignition is described in this paper. After charging the catalyst and pre-heating the first stage, the $N_2O$ was supplied at the first stage with the low mass flow rate, and then the $N_2O$ with the high flow rate was supplied into the second stage. Even though the $N_2O$ flow rate was high, it was decomposed by supplying the high temperature gas which was evolved from the $N_2O$ decomposition in the first stage. This multi-stage ignitor resulted in the decrease of the ignition time in comparison with the previous ignitor, and confirmed the possibility of $N_2O$ decomposition with the high flow rate using the multi-stage catalytic-ignition system.