• The Korean Journal of Ceramics
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• 제6권4호
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• pp.385-389
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• 2000

Residual stresses in epitaxial films were measured by X-ray diffraction method. Lattice strains of the (hkl) planes measured along particular Ψ-angles were converted to the in-plane stress according to the equation of stress-strain tensor conversion. Residual tensile stresses were observed in epitaxial PbTiO$_3$ films deposited on (100) SrTiO$_3$ substrate. Tensile stresses approximately 0.9 GPa were measured in Pb-rich films, while it increased to approximately 2.0 GPa with the decreasing of Pb content in the case of Pb-poor films, which ascribed to the formation of lead and oxygen vacancies (expressed as x in Pb$_1-x$TiO$_3-x$).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.222-222
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• 2011

Titanium dioxide (TiO2) has a number of applications in optics and electronics due to its superior properties, such as physical and chemical stability, high refractive index, good transmission in vis and NIR regions, and high dielectric constant. Atomic layer deposition (ALD), also called atomic layer epitaxy, can be regarded as a special modification of the chemical vapor deposition method. ALD is a pulsed method in which the reactant vapors are alternately supplied onto the substrate. During each pulse, the precursors chemisorb or react with the surface groups. When the process conditions are suitably chosen, the film growth proceeds by alternate saturative surface reactions and is thus self-limiting. This makes it possible to cover even complex shaped objects with a uniform film. It is also possible to control the film thickness accurately simply by controlling the number of pulsing cycles repeated. We have investigated the ALD of TiO2 at 100$^{\circ}C$ using precursors titanium tetra-isopropoxide (TTIP) and H2O on -O, -OH terminated Si surface by in situ X-ray photoemission spectroscopy. ALD reactions with TTIP were performed on the H2O-dosed Si substrate at 100$^{\circ}C$, where one cycle was completed. The number of ALD cycles was increased by repeated deposition of H2O and TTIP at 100$^{\circ}C$. After precursor exposure, the samples were transferred under vacuum from the reaction chamber to the UHV chamber at room temperature for in situ XPS analysis. The XPS instrument included a hemispherical analyzer (ALPHA 110) and a monochromatic X-ray source generated by exciting Al K${\alpha}$ radiation (h${\nu}$=1486.6 eV).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.176-176
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• 2007

Flat-panel direct conversion detectors used in compound substance of semiconductor are being studied for digital x-ray imaging. Recently, such detectors are deposited by physical vapor deposition(PVD) generally. But, most of materials (HgI2, PbI2, TlBr, PbO) deposited by PVD have shown difficult fabrication and instability for large area x-ray imaging. Consequently, in this paper, we propose applicable potentialities for screen printing method that is coated on a substrate easily. It is compared to electrical properties among semiconductors such as $HgI_2$, $PbI_2$, PbO, HgBrI, InI, and $TlPbI_3$ under investigation for direct conversion detectors. Each film detector consists of an ~25 to $35\;{\mu}m$ thick layer of semiconductor and was coated onto the substrate. Substrates of $2cm{\times}2cm$ have been used to evaluate performance of semiconductor radiation detectors. Dark current, sensitivity and physics properties were measured. Leakage current of $HgI_2$ as low as $9pA/mm^2$ at the operation bias voltage of ${\sim}1V/{\mu}m$ was observed. Such a value is not better than PVD process, but it is easy to be fabricated in high quality for large area x-ray Imaging. Our future efforts will concentrate on optimization of growth of film thickness that is coated onto a-Si TFT array.

• 치과방사선
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• 제10권1호
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• pp.57-61
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• 1980

In dental roentgenograph it is of mutual benefit to the patient and the dentist to use the minimum amount of radiation capable of producing roentgenograms with maximum interprtive informations. Recent increases in the number of diagnostic x-ray examinations made in this country have caused attention to be paid to the quantity of radiation delivered to the population and operator. The purposes of this study was to assess the quality of dental x-ray units, the amount of films, the average processing procedures and the radiation protection methods in korea. The results were as following: 1. Most of radiation generating system were used in low voltage such as 60Kvp, 10㎃. 2. High sensitivity films such as 'D' group of Kodak or Rinn were mainly used and average 14.7 films used per weeks. 3. Some dentists practiced visual processing technic in simple dark room, and others used instant films. 4. 68.26% of patient held the film themselves, but 27.30% were assisted by dentists film holding. 5. In radiation protection method, 7.85% of dentists had protection equipments such as protective barrier, 2.73% wore protective apron, 27.9% made it a rules to avoid beam, and 7.51% used to maintain a distance from the radiation source.

• 대한방사선기술학회지:방사선기술과학
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• 제23권1호
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• pp.13-19
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• 2000

We have presented with the "A study on overexposure rate according to over-density in chest X-ray radiography(I)" last year. In this report, We could calculate the entrance skin dose from chest X-ray film density the formula $I_0=Ix/e^{-{\mu}x}{\times}mG$, (mG is Bucky factor) was used to deliver the skin dose. At that time, There was two problems that the Bucky factor from maker was not equal to field experience and the field size influenced on the Attenuation Rate. The experiment of Bucky factor was done from film method and retried the Attenuation Rate of Acryle phantom according to Good & Poor geometry. As the results, The Bucky factor from maker higher than in this experiments $30{\sim}40%$. The Attenuation Rate in good geometric condition brings about a little alteration compare with poor geometric condition. In the field experiment, we could get the chest image with very low entrance skin radiation dose $29.3{\mu}Sv$, especially with air gap methode, the entrance skin dose was detected $10{\mu}Sv$.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 추계학술발표대회
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• pp.32.1-32.1
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• 2011

Ultra thin tantalum nitride (TaNx) films with various thicknesses (10 nm to 40 nm) have been deposited by rf magnetron sputtering technique on glass substrates. The as deposited films were systematically characterized by several analytical techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, atomic force microscopy, UV-Vis-NIR double beam spectrophotometer and four point probe method. From the XRD results, the as deposited films are in amorphous nature, irrespective of the film thicknesses. The films composition was changed greatly with increasing the film thickness. SEM micrographs exhibited the densely pack microstructure, and homogeneous surface covered by small size grains at lower thickness deposited films. The surface roughness of the films was linearly increases with increasing the films thickness, consequently the transmittance decreased. The absorption edge was shifted towards higher wavelength as the film thickness increases.

• Transactions on Electrical and Electronic Materials
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• 제12권2호
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• pp.76-79
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• 2011

In order to improve efficiency and make a new material thin film, we prepared the Al-In-Sn-ZnO thin film on a glass substrate at room temperature using a Facing Target Sputtering (FTS) system. The FTS system was designed to array two targets that face each other. Two different kinds of targets were installed on the FTS system. We used an ITO ($In_2O_3$ 90wt%, $SnO_2$ 10wt%) target and an AZO (ZnO 98wt%, $Al_2O_3$ 2wt%) target. The AIZTO films were deposited using different applied powers to the targets. The as-deposited AIZTO thin films were investigated using a UV/VIS spectrometer, an X-ray diffratometer (XRD), and Energy Dispersive X-ray spectroscopy (EDX).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.89-93
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• 1995

Effects of hydrogenation in amorphous silicon rile growths on Solid Phase Crystallization (SPC) was investigated using x-ray diffractometry, energy dispersive Spectroscopy, and Raman spectrum. Interdiffusion of barium(Ba) and aluminum(Al) compounds of corning substrate was observed in both of rf sputtering and LFCVD films under the low temperature(580$^{\circ}C$) annealing. Low degree of crystallinity resulted from the interdiffusion was obtained. Highly applicable degree of crystallinity was obtained through the mechanical damage induced surface activation on amorphous silicon films. X-ray diffraction intensity of (111) orientation was used to characterize the degree of crystallinity of SPC. Nucleation and growth rate in SPC could be controllable through the employed surface treatment. IIydrogenated LPCVD films showed the superior crystallinity to non-hydrogenated sputtering films. Insignificant effects of activation treatment in sputtered film was of activation treatment in sputtered film was observed on SPC.

• 대한방사선기술학회지:방사선기술과학
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• 제1권1호
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• pp.15-24
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• 1978

The characteristics of the rare earth phosphors intensifying screen (LM-6, Grenex-8) as compared with $CaWO_4$ intensifying screen had been studied utilizing several common x-ray films, and found the following results. 1. Compared with the conventional CaWO4 intensifying screen, the rare earth phosphors intensifying screen was found to be more sensitive over to 1.26-3.47 times. So the radiation exposure could be reduced to 1/1.26 -1/3.47. 2. Sharpness as well as the film speed were both increased. So the motion blurring and geometrical unsharpness could be decreased. 3. In spite of that the film speed was increased, photographic contrast was kept up. Therefore, the more ideal film of greater latitude could be obtained. 4. The effects of the rare earth phosphors intensifying screen would be much increased as using with orthochromatic x-ray films.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.464-466
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• 2000

AIN thin films have been prepared by reactive sputtering method, using facing targets sputtering system with a DC power supply which can deposit a high quality thin film and control deposition condition in all range of nitrogen. The crystallographic characteristics of AIN thin films on N$_2$/Ar ratio was investigated by alpha-step and X-ray diffraction. As a result, the AIN film deposited at the pressure ratio of the nitrogen of 30% revealed strong X-ray diffraction intensity under substrate temperature 25$^{\circ}C$ and applied current 0.4A.