• Journal of Powder Materials
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• v.31 no.3
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• pp.213-219
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• 2024

Additive Manufacturing (AM) is a process that fabricates products by manufacturing materials according to a three-dimensional model. It has recently gained attention due to its environmental advantages, including reduced energy consumption and high material utilization rates. However, controlling defects such as melting issues and residual stress, which can occur during metal additive manufacturing, poses a challenge. The trial-and-error verification of these defects is both time-consuming and costly. Consequently, efforts have been made to develop phenomenological models that understand the influence of process variables on defects, and mechanical/ electrical/thermal properties of geometrically complex products. This paper introduces modeling techniques that can simulate the powder additive manufacturing process. The focus is on representative metal additive manufacturing processes such as Powder Bed Fusion (PBF), Direct Energy Deposition (DED), and Binder Jetting (BJ) method. To calculate thermal-stress history and the resulting deformations, modeling techniques based on Finite Element Method (FEM) are generally utilized. For simulating the movements and packing behavior of powders during powder classification, modeling techniques based on Discrete Element Method (DEM) are employed. Additionally, to simulate sintering and microstructural changes, techniques such as Monte Carlo (MC), Molecular Dynamics (MD), and Phase Field Modeling (PFM) are predominantly used.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.132-132
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• 2011

For the programming volume of PRAM, Ge2Sb2Te5(GST) thin films have been dominantly used and prepared by physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD). Among these methods, ALD is particularly considered as the most promising technique for the integration of PRAM because the ALD offers a superior conformality to PVD and CVD methods and a digital thickness control precisely to the atomic level since the film is deposited one atomic layer at a time. Meanwhile, although the IST has been already known as an optical data storage material, recently, it is known that the IST benefits multistate switching behavior, meaning that the IST-PRAM can be used for mutli-level coding, which is quite different and unique performance compared with the GST-PRAM. Therefore, it is necessary to investigate a possibility of the IST materials for the application of PRAM. So far there are many attempts to deposit the IST with MOCVD and PVD. However, it has not been reported that the IST can be deposited with the ALD method since the ALD reaction mechanism of metal organic precursors and the deposition parameters related with the ALD window are rarely known. Therefore, the main aim of this work is to demonstrate the ALD process for IST films with various precursors and the conformal filling of a nano size programming volume structure with the ALD?IST film for the integration. InSbTe (IST) thin films were deposited by ALD method with different precursors and deposition parameters and demonstrated conformal filling of the nano size programmable volume of cell structure for the integration of phase change random access memory (PRAM). The deposition rate and incubation time are 1.98 A/cycle and 25 cycle, respectively. The complete filling of nano size volume will be useful to fabricate the bottom contact type PRAM.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.10
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• pp.779-784
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• 2001

In this work, we studied the characteristics of nitride films for the optimization of PMD(pro-metal dielectric) linear process, which can be applied to the recent semiconductor manufacturing process. We split the deposit condition of nitride films into four parts such as PO(protect overcoat) nitride, baseline, low hydrogen and high stress and low hydrogen, respectively. We tried to find out correlation between BPSG deposition and densification. In order to analyze the changes of Si-H and Si-NH-Si bonding density, we used FTIR area method. We also investigated the crack generation on wafer edge after BPSG densification, and the changes of nitride film stress as a function of RF power variation to judge whether the deposited films.

• Journal of the Korean Graphic Arts Communication Society
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• v.29 no.3
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• pp.133-142
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• 2011

We produce a photosensitive convex plate to research a Nickel metal relief printing plate using galvanic process. A Method for preparing DLC convex plate that is metalized on Nickel metal relief printing plate using CVD(Chemical Vapor Deposition) process and $N_2DLC$-convex plate that is DLC metalized thin film layer of $N_2$ plasma surface treatment are comprised. DLC thin film layers on Nickel surface are fragile. The results of the research indicate that the coefficient of friction on DLC metalized thin film layer is relatively low than Nickel surface and the durability of Nickel surface coated DLC metalized thin film layer is superior to Nickel surface. A relative evaluation of three form plate wetting properties using varnish liquid-drop plate indicates superior printing aptitudes for $N_2DLC$, DLC, Nichel plate order as above.

• Progress in Superconductivity and Cryogenics
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• v.7 no.3
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• pp.9-12
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• 2005

[ $Y_1Ba_2Cu_3O_{7-8}$ ] (YBCO) coated conductor has been fabricated by batch-type process using oxide-precursor-based metal-organic deposition (MOD) method. The batch-type process can be scaled up more simply to Produce long-length YBCO conductor than the reel-to-reel process. Also, it has less handling problems and is adequate to the ambient gas environment. In this work, YBCO oride powder was used as a starting precursor for MOD method. After reel-to-reel dip coating process, me ter-long-buffered metal tape was wound around a cylinder and underwent calcination and annealing processes. Annealed YBCO films showed good c-axis alignment and dense surface morphology with no cracks, but exhibited very low critical current density of $10^5\;A/cm^2$.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1632-1635
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• 2007

We developed a novel growth method of CNTs on metal substrate for device applications, deposited by a triode direct current plasma enhanced chemical vapor deposition (dc-PECVD). With resist-assisted patterning (RAP) method, we had grown CNTs on metal substrate, which were strongly bonded with metal substrate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.7-7
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• 2010

Indium tin oxide (ITO) - SWNT nano crystalline composites was synthesized at low temperature(${\sim}250^{\circ}C$)using Nano Cluster Deposition technique by Metal Orhoganic Chemical Vapor Deposition method. XRD patterns of ITO- SWNT composite shows pure cubic phases without any secondary phase. I-V measurement gives resistance of 12 ohms for Sn doped (3 wt %) indium oxide-SWNT composites. The electrical conductivity of the nano composites is significantly enhanced compared to the SWNT.

• Journal of Industrial Technology
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• v.35
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• pp.89-94
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• 2015

Graphene is a carbon-based two dimensional honeycomb lattice with monoatomic thickness and has attracted much attention due to its superior mechanical, electronic, and physical properties. Here, we present a synthesis of high quality graphene on Pt substrate using a chemical vapor deposition (CVD). We optimized synthesis condition with various parameters such as synthesis temperature, time, and cooling rate. Based on the results, we concluded that graphene synthesis is driven by mainly carbon adsorption on surface rather than precipitation of carbon which is dominant in other metal substrate. In addition, Pt substrate can be repeatedly used several times with high quality graphene.

• Journal of Welding and Joining
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• v.31 no.4
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• pp.13-16
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• 2013

In this research, laser cladding characteristics were investigated for various filler metal feeding methods such as powder, cold wire, and hot wire feeding. Appropriate parameter window, deposition rate, material efficiency and dilution for each filler feeding method were evaluated with same laser power and cladding speed range. Laser powder cladding has wider process parameter window but higher material efficiency and lower dilution were achieved by laser wire cladding. Among these feeding methods, laser hot-wire cladding showed best efficiency in material usage and deposition rate.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1136-1139
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• 2009

Recently, various Ni doping systems and thermal annealing systems have been developed for fabrication of polycrystalline silicon film using SGS (super grain silicon) for medium and largesize AMOLED panels. In this study, we compare the potential of Ni doping systems including ALD (atomic layer deposition), AMD (atmospheric metal deposition), in-line sputter, and crystallization annealing systems including batch type furnace, inline furnace, and RTA (rapid thermal annealing) developed for the SGS method. Additional requirements for those systems to be used for mass production of large AMOLED TVs are suggested based on evaluation results for both poly-Si films and TFT backplanes.