• Proceedings of the Korea Association of Crystal Growth Conference
• /
• 1998.06a
• /
• pp.173-176
• /
• 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.

• Journal of the Korean Ceramic Society
• /
• v.56 no.3
• /
• pp.277-283
• /
• 2019

We have examined minimization of the number of impurity particles by replacing the load-lock chamber materials of the chemical vapor deposition equipment through optimization of the pumping method in the deposition chamber. In order to reduce the number of impurity particles in the chamber, the load-lock spacer material was changed from monomer casting nylon to Torlon. Furthermore, we controlled the pumping speed and number of pumping ports, which resulted in a reduction in the impurity particle generation from 2.67% to 0.52%. This study revealed that the selection of the material for the parts of a chemical vapor deposition chamber can minimize particle generation, thereby presenting a method of optimization method of the chemical vapor deposition chamber.

• Journal of the Korean institute of surface engineering
• /
• v.27 no.1
• /
• pp.36-44
• /
• 1994

The TiN films were deposited on the stainless substrates using arc vapor ion deposition process to in-vestigated the wear resistance. Pin-on-disc tests were performed to measure the volume wear loss of TiN films. The substrate bias voltages and nitrogen flow rates were selected as the deposition parameters of TiN films. It was found that the wear resistance of TiN films was enhanced with increasing bias voltages(0~-300 V) and nitrogen flow rates(220~380 SCCM). The volume wear loss TiN films were about 9.5~2.1$\times$$10^{-3}mm^3$ and 3.5~2.2$\times$$10^{-3}mm^3$ with bias voltages and nitrogen flow rates, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07a
• /
• pp.185-190
• /
• 2003

In this paper, it was demonstrated that the organic thin film transistors were fabricated by the organic gate insulators with vapor deposition polymerization (VDP) processing. In order to form polyimide as a gate insulator, vapor deposition polymerization process was also introduced instead of spin-coating process, where polyimide film was co-deposited by high-vacuum thermal evaporation from 4,4'-oxydiphthalic anhydride (ODPA) and 4,4'-oxydianiline (ODA) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and ODA, and cured at $150^{\circ}C$ for 1hr. Electrical output characteristics in our organic thin film transistors using the staggered-inverted top-contact structure obtained to the saturated slop in the saturation region and the subthreshold non-linearity in the triode region. Field effect mobility, threshold voltage, and on-off current ratio in $0.45\;{\mu}m$ thick gate dielectric layer were about $0.17\;cm^2/Vs$, -7 V, and $10^6\;A/A$, respectively. Details on the explanation of compared to organic thin-film transistors (OTFTS) electrical characteristics of ODPA-ODA and 6FDA-ODA as gate insulators by fabricated thermal co-deposition method.

• Korean Journal of Materials Research
• /
• v.12 no.11
• /
• pp.850-855
• /
• 2002

Silica powders were prepared from $SiCl_4$-$H_2$O system by chemical vapor deposition process, and investigated on size control of the products with reaction conditions. The products were amorphous and nearly spherical particles with 130nm~50nm in size. The size distribution became narrow with the increase of [$H_2$O]/[SiCl$_4$] concentration ratio. The particle size decreased with the increase of reaction temperature, [$H_2$O]/[SiCl$_4$] concentration ratio and total flow rate. The specific surface area measured by BET method was about three times larger than that of electron microscope method.

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

• Electrical & Electronic Materials
• /
• v.9 no.8
• /
• pp.776-782
• /
• 1996

The electrical properties of vapor deposition polymerized polymide thin films for getting an in-line system with manufacturing process of semiconductor device, have been studied. Polyimide thin films fabricated by vapor deposition polymerization(VDP) method based on PMDA and 4,4'-DDE monomer were confirmed by FT-IR spectra. It is found that the major conduction carriers of thin films are ions, and the hopping length of ions is almost same with monomer length at the temperature over 120.deg. C through the analysis of electrical conduction mechanism. Also, The activation energy is about 0.69 eV at the temperature of >$30^{\circ}C$ - >$150^{\circ}C$ and it is shown that the resistivity at which thin films can be used as an insulating film between layers of semiconductor device, is 3.2*10$^{15}$ .ohm.cm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07a
• /
• pp.190-193
• /
• 2002

The processing technology of organic thin-film transistors (Ons) performances have improved fur the last decade. Gate insulator layer has generally used inorganic layer, such as silicon oxide which has properties of a low electrical conductivity and a high breakdown field. However, inorganic insulating layers, which are formed at high temperature, may affect other layers termed on a substrate through preceding processes. On the other hand, organic insulating layers, which are formed at low temperature, dose not affect pre-process. Known wet-processing methods for fabricating organic insulating layers include a spin coating, dipping and Langmuir-Blodgett film processes. In this paper, we propose the new dry-processing method of organic gate dielectric film in field-effect transistors. Vapor deposition polymerization (VDP) that is mainly used to the conducting polymers is introduced to form the gate dielectric. This method is appropriate to mass production in various end-user applications, for example, flat panel displays, because it has the advantages of shadow mask patterning and in-situ dry process with flexible low-cost large area displays. Also we fabricated four by four active pixels with all-organic thin-film transistors and phosphorescent organic light emitting devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.114-115
• /
• 2007

In this paper, it was demonstrated that organic thin-film transistors (OTFTs) were fabricated with the organic passivation layer by vapor deposition polymerization (VDP) processing, In order to form polymeric film as an passivation layer, VDP process was also introduced instead of spin-coating process, where polymeric film was co-deposited by high-vacuum thermal evaporation from 6FDA and ODA followed by curing, Field effect mobility, threshold voltage, and on-off current ratio with 450-nm-thick organic passivation layer were about $0.21\;cm^2/Vs$, IV, and $1\;{\times}\;10^5$, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.21 no.3
• /
• pp.371-379
• /
• 1997

A theoretical study for a forced uniform flow impinging on a rotating disk, typically involved in Chemical Vapor Deposition(CVD) and Vapor-phase Axial Deposition(VAD) processes, has been carried out. A set of exact solutions for flow and temperature fields are developed by employing a similarity variable obtained from force balance on a control volume near the disk. The solutions depend on the rotating speed of the disk, .omega., and the forced flow speed toward the disk, a. For constant forced flow speed, the overall boundary layer thickness decreases when the rotating speed increases. Approximately 5%, 15%, and 30% decreases of the thickness are obtained for .omega./a = 2, 5, and 10, respectively, compared to the case of .omega./a = 0 (axisymmetric stagnation point flow). For constant rotating disk speed the boundary layer thickness immediately decreases as the forced flow speed increases, compared to the case of .omega./a .rarw. .inf. (induced flow near a rotating disk). Effects of .omega. and a on heat transfer coefficient are studied and explained with the boundary layer characteristics.