• Applied Microscopy
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• 제45권3호
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• pp.119-125
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• 2015

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted significant attention due to their unique and exotic properties attributed to their low dimensionality. In particular, semiconducting 2D TMDCs such as $MoS_2$, $WS_2$, $MoSe_2$, and $WSe_2$ have been demonstrated to be feasible for various advanced electronic and optical applications. In these regards, process to synthesize high quality 2D TMDCs layers with high reliability, wafer-scale uniformity, controllable layer number and excellent electronic properties is essential in order to use 2D TMDCs in practical applications. Vapor deposition techniques, such as physical vapor deposition, chemical vapor deposition and atomic layer deposition, could be promising processes to produce high quality 2D TMDCs due to high purity, thickness controllability and thickness uniformity. In this article, we briefly review recent research trend on vapor deposition techniques to synthesize 2D TMDCs.

• 한국재료학회지
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• 제33권11호
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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.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 14TH KACG TECHNICAL MEETING AND THE 5TH KOREA-JAPAN EMGS (ELECTRONIC MATERIALS GROWTH SYMPOSIUM)
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• pp.173-176
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• 1998

Epitaxial Si layers were deposited on n- or p-type Si(100) substrates by hot-wall chemical vapor deposition (CVD) technique using the {{{{ {SiH }_{ 2} {Cl }_{2 } - {H }_{ 2} }}}}chemistry. Thermodynamic calculations if the Si-H-Cl system were carried out to predict the window of actual Si deposition procedd and to investigate the effects of process variables(i.e., the deposition temperature, the reactor pressure, and the source gas molar ratios) on the growth of epitaxial layers. The calculated optimum process conditions were applied to the actual growth runs, and the results were in good agreement with the calculation. The expermentally determined optimum process conditions were found to be the deposition temperature between 900 and 9$25^{\circ}C$, the reactor pressure between 2 and 5 Torr, and source gad molar ration({{{{ {H }_{2 }/ {SiH }_{ 2} {Cl }_{2 } }}}}) between 30 and 70, achieving high-quality epitaxial layers.

• Bulletin of the Korean Chemical Society
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• 제28권11호
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• pp.2056-2060
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• 2007

A successful combination of “oxygen-assisted chemical vapor deposition (CVD) process” and Co catalyst nanoparticles to grow highly pure single walled carbon nanotubes (SWNTs) was demonstrated. Recently, it was reported that addition of small amounts of oxygen during CVD process dramatically increased the purity and yield of carbon nanotubes. However, this strategy could not be applied for discrete Fe nanoparticle catalysts from which appropriate yields of SWNTs could be grown directly on solid substrates, and fabricated into field effect transistors (FETs) quite efficiently. The main reason for this failure is due to the carbothermal reduction which results in SiO2 nanotrench formation. We found that the oxygen-assisted CVD process could be successfully applied for the growth of highly pure SWNTs by switching the catalyst from Fe to Co nanoparticles. The topological morphologies and p-type transistor electrical transport properties of the grown SWNTs were examined by using atomic force microscope (AFM), Raman, and from FET devices fabricated by photolithography.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.248-248
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• 2012

Synthesis graphene on Cu substrate by plasma-enhanced chemical vapor deposition (PE-CVD) is investigated and its quality's affection factors are discussed in this work. Compared with the graphene synthesized at high temperature in chemical vapor deposition (CVD), the low-temperature graphene film by PE-CVD has relatively low quality with many defects. However, the advantage of low-temperature is also obvious that low melting point materials will be available to synthesize graphene as substrate. In this study, the temperature will be kept constant in $400^{\circ}C$ and the graphene was grown in plasma environment with changing the plasma power, the flow rate of precursors, and the distance between plasma generator coil and substrates. Then, we investigate the effect of temperature and the influence of process variables to graphene film's quality and characterize the film properties with Raman spectroscopy and sheet resistance and optical emission spectroscopy.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.421-421
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• 2012

Graphene has drawn enormous attention owing to its outstanding properties, such as high charge mobility, excellent transparence and mechanical property. Synthesis of Graphene by chemical vapor deposition (CVD) is an attractive way to produce large-scale Graphene on various substrates. However the fatal limitation of CVD process is high temperature requirement(around $1,000^{\circ}C$), at which many substrates such as Al substrate cannot endure. Therefore, we propose plasma enhanced CVD (PECVD) and decrease the temperature to $400^{\circ}C$. Fig. 1 shows the typical structure of RF-PECVD instrument. The quality of Graphene is affected by several variables. Such as plasma power, distance between substrate and electronic coil, flow rate of source gas and growth time. In this study, we investigate the influence of these factors on Graphene synthesis in vacuum condition. And the results were checked by Raman spectra and conductivity measurement.

• 한국표면공학회지
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• 제56권6호
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• pp.341-352
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• 2023

This paper reviews the potentials of a rotary chemical vapor deposition (RCVD) process for nanomaterial synthesis and coating on powder-based materials. The rotary reactor offers a significant improvement over traditional CVD methods having horizontal and fixed reaction chambers. The RCVD system yields enhanced productivity and surface coating uniformity of nanoparticles applied in various purposes, such as efficient heat dissipation, surface hardness enhancement, and enhanced energy storage performances. The effectiveness of the RCVD system would open up new possibilities in various applications because uniform coating on powder-based materials with massive productivity is inevitable to develop multi-functional materials with high reliability.

• 반도체디스플레이기술학회지
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• 제23권2호
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• pp.87-91
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• 2024

SiO₂, renowned for its excellent insulating properties, has been used in the semiconductor industry as a valuable dielectric material. High-quality SiO₂ films find applications in gate spacers and interlayer insulation gap-fill oxides, among other uses. One of the prevalent methods for depositing these SiO₂ films is plasma enhanced chemical vapor deposition (PECVD) favored for its relatively low processing costs and ability to operate at low temperatures. However, compared to the increasingly utilized atomic layer deposition (ALD) method, PECVD exhibits inferior film characteristics such as uniformity. This study aims to produce SiO₂ films with uniformity as close as possible to those achieved by ALD through the adjustment of PECVD process parameters. we conducted a total of nine PECVD processes, varying the process time and gas flow rates, which were identified as the most influential factors on the PECVD process. Furthermore, ellipsometry analysis was employed to examine the uniformity variations of each process. The experimental results enabled us to elucidate the relationship between uniformity and deposition rate, as well as the impact of gas flow rate and deposition time on the process outcomes. Additionally, thickness measurements obtained through ellipsometer facilitate the identification of optimal process parameters for PECVD.

• 진공이야기
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• 제1권3호
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• pp.9-13
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• 2014

Vacuum growth of thin films via chemical vapor deposition (CVD) methods has been extensively used in modern semiconductor and flat panel display industries. The CVD processes have a wide range of variation and are categorized according to their working conditions, power sources, precursor materials, and so forth. Basic components and process steps common to all CVD branches are discussed. In addition, characteristics and applications of two major CVD techniques - LPCVD and PECVD - are reviewed briefly.

• Carbon letters
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• 제25권
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• pp.25-32
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• 2018

In this study, a thermal-gradient chemical vapor infiltration (TG-CVI) process was numerically studied in order to enhance the deposition uniformity within the preform. The computational fluid dynamics technique was used to solve the governing equations for heat transfer and gas flow during the TG-CVI process for two- and three-dimensional (2-D and 3-D) models. The temperature profiles in the 2-D and 3-D models showed good agreement with each other and with the experimental results. The densification process was investigated in a 2-D axisymmetric model. Computation results showed the distribution of the SiC deposition rate within the preform. The results also showed that using two-zone heater gave better deposition uniformity.