• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.6
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• pp.459-466
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• 2000

For the applications in the ultra-large-scale-integration (ULSI) metallization processing copper thin films have been prepared by metal organic chemical vapor deposition (MOCVD) technology on TiN/Si substrates. The films have been deposited with varying the experimental conditions of substrate temperatures and copper source vapor pressures. The films were then annealed in a vacuum condition after the deposition and the annealing effect to the electrical conductivity of the films was measured. The grain size and the crystallinity of the films were observed to be increased by the post annealing and the electrical conductivity was also increased. The best electrical property of the copper film was obtained by in-situ annealing treatment at above 40$0^{\circ}C$ for the sample prepared at 18$0^{\circ}C$ of the substrate temperature.

• Composites Research
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• v.36 no.5
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• pp.377-382
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• 2023

To enhance the performance of graphene-based devices, it is of great importance to better understand the interfacial interaction of graphene with its underlying substrates. In this study, the adhesion energy of monolayer graphene placed on dielectric substrates was characterized using mode I fracture tests. Large-area monolayer graphene was synthesized on copper foil using chemical vapor deposition (CVD) with methane and hydrogen. The synthesized graphene was placed on target dielectric substrates using polymer-assisted wet transfer technique. The monolayer graphene placed on a substrate was mechanically delaminated from the dielectric substrate by mode I fracture tests using double cantilever beam configuration. The obtained force-displacement curves were analyzed to estimate the adhesion energies, showing 1.13 ± 0.12 J/m² for silicon dioxide and 2.90 ± 0.08 J/m² for silicon nitride. This work provides the quantitative measurement of the interfacial interactions of CVD-grown graphene with dielectric substrates.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.405-410
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• 2011

A study on chemical vapor deposition(CVD) of $WO_3$ and the electrochromic properties of the CVD $WO_3$ films have been carried out. The crystalinity, purity, and growth rate of the films depending on substrate temperatures are investigated. The highest growth rate is $8{\mu}m/min$ at the substrate temperatures above $300^{\circ}C$ and the estimated activation energy for overall film growth is about 45.9 kJ/mol at the temperatures of $225{\sim}275^{\circ}C$, where the CVD process is controlled by a surface reaction kinetics. The films grown below $275^{\circ}C$ are amorphous, while those deposited above $300^{\circ}C$ are crystalline. The effects of thickness and deposition temperature of the $WO_3$ films on electrochromic activity are also investigated. The coloration efficiency of the films increases with increase in film thickness and decrease in deposition temperature.

• Journal of the Korean institute of surface engineering
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• v.18 no.3
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• pp.116-124
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• 1985

Chemical vapor deposition of $SnO_2$ on Pyrex glass substrate has been investigated using $SnCl_4$ and Oxygen at relatively low temperatures(300-500$^{\circ}C$). The critical flow rate, which delineated the surface reaction controlled region from the mass transfer controlled region, was increased with deposition temperature. The apparent activation energy obtained in surface reaction controlled region was about 6Kcal/mole. The results show that deposition rate, electrical conductivity and transmittance were affected mainly by partial pressure of $SnCl_4$, but little by partial pressure f oxygen. The % transmission of 5000A-thick $SnO_2$ film was about 90% in visible spectrum region and sheet resistance was varied in 0.1-10${\Omega}$ per square shaped portion of the outer surface of the oxide.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 2000.06a
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• pp.127-142
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• 2000

The charged cluster model states that chemical vapor deposition (CVD) begins with gas phase nucleation of charged clusters followed by cluster deposition on a substrate surface to form a thin film. A two-chambered CVD system, separated by a 1-mm orifice, was used to study gold deposition by thermal evaporation in order to determine if the CCM applies in this case. At a filament temperature of 1523 and 1773 K, the presence of nano-meter sized gold clusters was found to be positive and the cluster size and size distribution increased with increasing temperature. Small clusters were found to be amorphous and they combined with clusters already deposited on a substrate surface to form larger amorphous clusters on the surface. This work revealed that gold thin films deposited on a mica surface are the result of the sticking of 4-10 nm clusters. The topography of these films was similar to those reported previously under similar conditions.

• Korean Journal of Materials Research
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• v.33 no.11
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• pp.491-496
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• 2023

As the demand for p-type semiconductors increases, much effort is being put into developing new p-type materials. This demand has led to the development of novel new p-type semiconductors that go beyond existing p-type semiconductors. Copper iodide (CuI) has recently received much attention due to its wide band gap, excellent optical and electrical properties, and low temperature synthesis. However, there are limits to its use as a semiconductor material for thin film transistor devices due to the uncontrolled generation of copper vacancies and excessive hole doping. In this work, p-type CuI semiconductors were fabricated using the chemical vapor deposition (CVD) process for thin-film transistor (TFT) applications. The vacuum process has advantages over conventional solution processes, including conformal coating, large area uniformity, easy thickness control and so on. CuI thin films were fabricated at various deposition temperatures from 150 to 250 ℃ The surface roughness root mean square (RMS) value, which is related to carrier transport, decreases with increasing deposition temperature. Hall effect measurements showed that all fabricated CuI films had p-type behavior and that the Hall mobility decreased with increasing deposition temperature. The CuI TFTs showed no clear on/off because of the high concentration of carriers. By adopting a Zn capping layer, carrier concentrations decreased, leading to clear on and off behavior. Finally, stability tests of the PBS and NBS showed a threshold voltage shift within ±1 V.

• Journal of the Korean Ceramic Society
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• v.45 no.9
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• pp.567-571
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• 2008

The properties of a grown film by the chemical vapor deposition process depend on the deposition temperature because the deposition mechanism of the CVD film is controlled by the deposition temperature. The preferred orientation of the zrC film changed from (111) to (220) or (200) with an increase of the deposition temperature. The grain size of the ZrC film changes from $0.8{\mu}m$ to $2.5{\mu}m$ in the range of 1350 to $1500^{\circ}C$. The hardness of the deposited ZrC film depended on the preferred orientation and the grain size. The hardness of the ZrC film deposited at $1400^{\circ}C$ was 31 GPa.

• Journal of Adhesion and Interface
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• v.24 no.3
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• pp.100-104
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• 2023

Van der Waals heterostructures have garnered significant attention in recent research due to their excellent electronic characteristics arising from the absence of dangling bonds and the exclusive reliance on Van der Waals forces for interlayer coupling. However, most studies have been confined to fundamental research employing the Scotch tape (mechanical exfoliation) method. We fabricated Van der Waals vertical heterojunction transistors to advance this field using materials exclusively grown via chemical vapor deposition (CVD). CVDgrown graphene was patterned through photolithography to serve as electrodes, while CVD-grown MoSe₂ was employed as the pickup/transfer material, resulting in the realization of Van der Waals heterojunction transistors with interlayer charge transfer effects. The electrical characteristics of the fabricated devices were thoroughly examined. Additionally, we observed variations in the transistor's performance based on the presence of defects in MoSe₂ layer.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.232.2-232.2
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• 2014

Since its discovery in 2004, graphene, a sp2-hybridized 2-Dimension carbon material, has drawn enormous attention. A variety of approaches have been attempted, such as epitaxial growth from silicon carbide, chemical reduction of graphene oxide and CVD. Among these approaches, the CVD process takes great attention due to its guarantee of high quality and large scale with high yield on various transition metals. After synthesis of graphene on metal substrate, the subsequent transfer process is needed to transfer graphene onto various target substrates, such as bubbling transfer, renewable epoxy transfer and wet etching transfer. However, those transfer processes are hard to control and inevitably induce defects to graphene film. Especially for wet etching transfer, the metal substrate is totally etched away, which is horrendous resources wasting, time consuming, and unsuitable for industry production. Thus, our group develops one-step process to directly grow graphene on glass substrate in plasma enhanced chemical vapor deposition (PECVD). Copper foil is used as catalyst to enhance the growth of graphene, as well as a temperature shield to provide relatively low temperature to glass substrate. The effect of growth time is reported that longer growth time will provide lower sheet resistance and higher VSG flakes. The VSG with conductivity of $800{\Omega}/sq$ and thickness of 270 nm grown on glass substrate can be obtained under 12 min growing time. The morphology is clearly showed by SEM image and Raman spectra that VSG film is composed of base layer of amorphous carbon and vertically arranged graphene flakes.

• Korean Journal of Materials Research
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• v.28 no.5
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• pp.279-285
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• 2018

Graphene is an interesting material because it has remarkable properties, such as high intrinsic carrier mobility, good thermal conductivity, large specific surface area, high transparency, and high Young's modulus values. It is produced by mechanical and chemical exfoliation, chemical vapor deposition (CVD), and epitaxial growth. In particular, large-area and uniform single- and few-layer growth of graphene is possible using transition metals via a thermal CVD process. In this study, we utilize polystyrene and boron oxide, which are a carbon precursor and a doping source, respectively, for synthesis of pristine graphene and boron doped graphene. We confirm the graphene grown by the polystyrene and the boron oxide by the optical microscope and the Raman spectra. Raman spectra of boron doped graphene is shifted to the right compared with pristine graphene and the crystal quality of boron doped graphene is recovered when the synthesis time is 15 min. Sheet resistance decreases from approximately $2000{\Omega}/sq$ to $300{\Omega}/sq$ with an increasing synthesis time for the boron doped graphene.