• Interaction and multiscale mechanics
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• v.1 no.1
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• pp.123-142
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• 2008

Current methodologies used for the inference of thin film stresses through curvature measurements are strictly restricted to stress and curvature states which are assumed to remain uniform over the entire film/substrate system. These methodologies have recently been extended to non-uniform stress and curvature states for the thin film subject to non-uniform, isotropic misfit strains. In this paper we study the same thin film/substrate system but subject to non-uniform, anisotropic misfit strains. The film stresses and system curvatures are both obtained in terms of the non-uniform, anisotropic misfit strains. For arbitrarily non-uniform, anisotropic misfit strains, it is shown that a direct relation between film stresses and system curvatures cannot be established. However, such a relation exists for uniform or linear anisotropic misfit strains, or for the average film stresses and average system curvatures when the anisotropic misfit strains are arbitrarily non-uniform.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.10-10
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• 2009

We have fabricated transparent and flexible thin film transistor(TFT) on polyethylene terephthalate(PET) substrate using Zinc Oxide (ZnO) and Indium Tin Oxide (ITO) film as active layer and electrode. The transfer printing method was used for printing the device layer on target plastic substrate at room temperature. This approach have an advantage to separate the high temperature annealing process to improve the electrical properties of ZnO TFT from the device process on plastic substrate. The resulting devices on plastic substrate presented mechanical and electrical properties similar with those on rigid substrate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.3
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• pp.329-332
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• 2004

ZnO thin films were grown with different plume-substrate angles by pulsed laser deposition (PLD) to control the amount of ablated species arriving on a substrate per laser shot. The angles between plume propagation direction and substrate plane (P-S angle) were 0$^{\circ}$, 45$^{\circ}$ and 90$^{\circ}$. The growth time was changed in order to adjust film thickness. From the XRD pattern exhibiting a dominant (002) and a minor (101) XRD peak of ZnO, all films were found to be well oriented along c-axis. From the AFM image, it was found that the grain size of ZnO thin film was increased, as P-S angle decreased. UV intensity investigated by PL (Photoluminescence) increased as P-S angle decreased.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.177-181
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• 2009

Compositional gradient CrNx coatings were fabricated using arc ion plating in Ar/$N_2$ gaseous mixture by gradually increasing $N_2$ flux rate from 0 to 120 SCCM. The effect of negative substrate bias on the film microstructure and mechanical properties were systematically investigated with XRD, GDOES, and SEM. The results show that substrate bias has an important influence on film growth and microstructure of gradient CrNx coatings. The coatings mainly crystallized in the mixture of hexagonal $Cr_{2}N$ and fcc CrN phases. By increasing substrate bias, film microstructure evolved from an apparent columnar structure to an equiaxed one. With increasing substrate bias, deposition rate first increased, and then decreased. The maximum of deposition rate was 15 nm/min obtained at a bias of -50V.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.10
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• pp.648-651
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• 2015

The characterizations of zinc oxide (ZnO) buffer layers grown by unbalanced magnetron (UBM) sputtering under various substrate temperatures for inverted organic solar cells (IOSCs) were investigated. UBM sputter grown ZnO films exhibited higher crystallinity with increasing the substrate temperature, resulting in uniform and large grain size. Also, the electrical properties of ZnO films are improved with increasing substrate temperature. In the results, the performance of IOSCs critically depended on the substrate temperature during the film growth because the crystalllinity of the ZnO film affect the carrier mobility of the ZnO film.

• Journal of Korean Vacuum Science & Technology
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• v.4 no.1
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• pp.18-22
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• 2000

For the enhancement of the nucleation density of the diamond film, we introduced the cyclic process. The cyclic process was carried out by the on/off control of CH$_4$ flow rate for a relatively short time (10 min), compared with the total reaction time (6 h). Prior to depositing the diamond film, we made the pretreated glass substrate via the unidirectional scratch using ∼l $\mu\textrm{m}$ size diamond powders. Diamond films were deposited on the pretreated glass substrate in a microwave plasma enhanced chemical vapor deposition (MPECVD) system. We observed the enhancement of the nucleation density of the diamond films caused by the cyclic process. Detailed surface morphologies of the substrate were investigated after the cyclic process. Based on these results, we discussed the cause for the enhancement of the nucleation density on the pretreated glass substrate by the cyclic process.

• Korean Journal of Materials Research
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• v.1 no.2
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• pp.93-98
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• 1991

The as-grown $YBa_2Cu_3O_{7-x}$ superconducting thin films on MgO(100) substrate have been prepared by a reactive coevaporation method. The superconducting transition temperature, surface morphology and crystalline quality were examined as a function of the substrate temperature ranging from $450^{\circ}C$ to $590^{\circ}C$. From the reflection high energy electron diffraction (RHEED) analysis, it was found the film consisted of almost amorphous phase with a halo pattern deposited at the substrate temperature of $450^{\circ}C$. The film deposited at the substrate temperature of $510^{\circ}C$ consisted of polycrystalline phase, showing a broad ring pattern. On the other hand, for the film deposited at $590^{\circ}C$, RHEED showed spotty pattern indicating that this film consisted of single crystal phase. It has rough film surface due to the surface outgrowth. The surface outgrowth increased as the substrate temperature increased from $510^{\circ}C$ to $590^{\circ}C$. the surface outgrowth may be due to the anisotropic growth rate. The highest transition temperature obtained in this study was $Tc_{zero}$ of 83K with $Tc_{onset}$ of 88K for the film deposited at $590^{\circ}C$ using activated RF oxygen plasma.

• Journal of the Korean Ceramic Society
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• v.31 no.2
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• pp.206-212
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• 1994

Effects of the film deposition process parameters on the properties such as deposition rate, etch rate, refractive index, stress and step coverage of plasma enhanced chemical vapor deposited (PECVD) tetraethylorthosilicate glass (TEOS) SiO2 film were investigated and analysed using SEM, FTIR and SIMS techniques. Increasing TEOS flow or decreasing O2 flow increased the deposition rate and the compressive stress of the oxide film but produced a less denser film. The deposition rate decreased owing to the decrease in the sticking coefficient of the TEOS and the O2 molecules onto the substrate Si with increasing the substrate temperature. Increasing the substrate temperature produced a denser film with a lower etch rate and the higher refractive index by lowering SiOH and moisture contents. Increasing the rf power increases the ion bombardment energy. This increase in energy, in turn, increases the deposition rate and tends to make the film denser. No appreciable changes were found in the deposition rate but the refractive index and the stress of the film decreased with increasing the deposition pressure. The carbon content in the plasma TEOS CVD oxide film prepared under our standard deposition conditions were very low according to the SIMS analysis results.

• Korean Journal of Materials Research
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• v.34 no.1
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• pp.55-62
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• 2024

Fluorine-doped tin oxide (FTO) has been used as a representative transparent conductive oxide (TCO) in various optoelectronic applications, including light emitting diodes, solar cells, photo-detectors, and electrochromic devices. The FTO plays an important role in providing electron transfer between active layers and external circuits while maintaining high transmittance in the devices. Herein, we report the effects of substrate rotation speed on the electrical and optical properties of FTO films during ultrasonic spray pyrolysis deposition (USPD). The substrate rotation speeds were adjusted to 2, 6, 10, and 14 rpm. As the substrate rotation speed increased from 2 to 14 rpm, the FTO films exhibited different film morphologies, including crystallite size, surface roughness, crystal texture, and film thickness. This FTO film engineering can be attributed to the variable nucleation and growth behaviors of FTO crystallites according to substrate rotation speeds during USPD. Among the FTO films with different substrate rotation speeds, the FTO film fabricated at 6 rpm showed the best optimized TCO characteristics when considering both electrical (sheet resistance of 13.73 Ω/□) and optical (average transmittance of 86.76 % at 400~700 nm) properties with a figure of merit (0.018 Ω^-1).

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1182-1184
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• 2006

A mica has been introduced as a new substrate material for the fabrication of the poly-Si TFTs. A poly-Si film is produced on the mica substrate at $550^{\circ}C$ by the nickel-induced crystallization and the poly-Si TFTs on the mica substrate are successfully fabricated for the first time.