• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.2032-2037
• /
• 2007

Numerical analysis was conducted to investigate the atomic layer deposition(ALD) of silicon nitride using silane and ammonia as precursors. The present study simulated the surface reactions for as-deposited $Si_3N_4$ as well as the kinetics for the reactions of $SiH_4$ and $NH_3$on the semiconductor wafer. The present numerical results showed that the ALD process is dependent on the activation constant. It was also shown that the low activation constant leads to the self-limiting reaction required for the ALD process. The inlet and wafer temperatures were 473 K and 823 K, respectively. The system pressure is 2 Torr.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.2702-2707
• /
• 2007

The purpose of this study is to calculate the behavior of molecules for the generation of homogeneous thin-films in the process of spray deposition. The calculation system was composed of a suface molecular region and droplet molecular region. The thin-film was generated when droplet molecules fell to surface molecules. Lennard-Jones potential had been used as intermolecular potential, and only attraction 때 d repulsion had been used for the behavior of the droplet on the solid surface. As results, the behavior of the droplet was so much influenced by the surface temperature in the spray deposition process. High temperature of surface has higher porosity and larger spread area. It was found that simulation results generally agreed well with previous the experimental results. This simulation result will be the foundation for the deposition processes of industry.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.327-330
• /
• 2004

Laser aided direct metal deposition (LADMD) process offers the ability to make a metal component directly from 3-D CAD dimensions. A 3-D object can be formed by repeating laser cladding layer by layer. The key of the build-up mechanism is the effective control of powder delivery and laser power to be irradiated into the melt-pool. A feedback control system using optical sensors is introduced to control laser power and powder mass flow rate. Using H13 tool steel and $CO_2$ laser system, comprehensive analysis are executed to test the efficiency of the system. In addition, the dimensional characteristics of directed deposited material are investigated with the parameters of deposition thickness, laser power, traverse speed and powder mass flow rate.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.25 no.1
• /
• pp.36-41
• /
• 2016

A method is proposed for the improvement of deposition reproducibility in the selective electrodeposition process using laser masking and DC voltage. Selective electrodeposition using laser masking and DC voltage can achieve a deposited layer with micro patterns. However, selective electrodeposition using laser masking and DC voltage have a critical problem: the lack of reproducibility in selective deposition. The reproducibility of selective electrodeposition can be improved by a new process that consists of laser masking, two-step electro-deposition, laser scribing, and ultrasonic cleaning. The experiments in this study show that the reproducibility of selective deposition can be successfully improved by the combination of two-step electrodeposition and laser scribing.

• Journal of the Korean Society for Heat Treatment
• /
• v.23 no.2
• /
• pp.75-82
• /
• 2010

A new advanced combined PVD/CVD technique of DLC film deposition has been developed. Deposition of a DLC film was carried out using a pulsed carbon arc discharge in vapor hydrocarbon atmosphere. The arc plasma enhancing CVD process promotes dramatic increase in the deposition rate and decrease of compressive stress as well as improvement of film thickness uniformity compared to that obtained with a single PVD pulsed arc process. The optical spectroscopy investigation reveals great increase in radiating components of $C_2$ Swan system molecular bands due to acetylene molecules decomposition. AFM, Raman spectroscopy, XPS and nano-indentation were used to characterize DLC films. The method ensures obtaining a new superhard DLC nano-material for deposition of protective coatings onto various industrial products including those used in medicine.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11b
• /
• pp.300-303
• /
• 2001

BSCCO thin films are fabricated via a co-deposition process by an ion beam sputtering with an ultra-low growth rate, and sticking coefficients of the respective elements are evaluated. The sticking coefficient of Bi element exhibits a characteristic temperature dependence : almost a constant value of 0.49 below $730^{\circ}C$ and decreases linearly with temperature over $730^{\circ}C$. This temperature dependence can be elucidated from the evaporation and sublimation rates of bismuth oxide, $Bi_{2}O_{3}$, from the film surface. It is considered that the liquid phase of the bismuth oxide plays an important role in the Bi 2212 phase formation in the co-deposition process.

• Journal of the Korean Society for Heat Treatment
• /
• v.5 no.2
• /
• pp.95-102
• /
• 1992

In this study, we tried to describe the quantitative model of TiN film structure which was deposited by PECVD process. The macro-grain growth behavior was studied at the various deposition pressures and times. As a result, It was confirmed that TiN films had the typical Zone 1 structure, and macro-columnar grains were, without reference to the deposition pressure, grown ballistic type by the growth-death competition following the equation, $Y=aX^2$, approximately obtained by regression analysis. Also, the thickness and the crystallization of TiN thin films were increased, the chlorine contents were decreased according to the decreasing of deposition pressure.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.02a
• /
• pp.133-136
• /
• 2003

The CeO$_2$ thin films were deposited on the biaxially textured Ni substrates by MOCVD process. The (200) oriented CeO$_2$ films were formed at the deposition temperature(Td) of 500~52$0^{\circ}C$, the oxygen partial pressure(PO2) of 0.90~3.33 torr and the deposition time(t) of 3~25 min. The surface roughness and gain size rapidly increased at Td $\geq$ 52$0^{\circ}C$ due to the grain growth. The surface roughness also increased as the deposition time increased. The optimized deposition conditions of the CeO$_2$ films for the YBCO coated conductor were Td= 500~51$0^{\circ}C$, PO2= 2.30 torr and t= 10~12 min.

• Proceedings of the KIEE Conference
• /
• 1997.07d
• /
• pp.1301-1303
• /
• 1997

This study was performed to investigate the deposition mechanism of $SiO_2$ by ArF excimer Laser(193nm) CVD with $Si_2H_6$ and $N_2O$ gas mixture and evaluate Laser CVD quantitatively by modeling. In this study, new model of $SiO_2$ deposition process by Laser CVD is introduced and deposition rates are simulated by computer with the basis on this modeling. And simulation results are compared with experimental results measured at various conditions such as reaction gas ratio, chamber pressure, substrate temperature and laser beam intensity.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 1996.10a
• /
• pp.234-238
• /
• 1996

In this paper, Plasma-Enhanced Chemical Vapor Deposition (PECVD) modeling using Polynomial Neural Networks (PNN) has been introduced. The deposition of SiO2 was characterized via a 25-1 fractional factorial experiment, was used to train PNNs using predicted squared error (PSE). The optimal neural network structure and learning parameters were determined by means of a second fractional factorial experiment. The optimized networks minimized both learning and prediction error. From these PNN process models, the effect of deposition conditions on film properties has been studied. The deposition experiments were carried out in a Plasma Therm 700 series PECVD system. The models obtained will ultimately be used for several other manufacturing applications, including recipe synthesis and process control.