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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Vacuum Society
Journal Basic Information
Journal DOI :
The Korean Vacuum Society
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Volume & Issues
Volume 10, Issue 4 - Dec 2001
Volume 10, Issue 3 - Oct 2001
Volume 10, Issue 2 - Jul 2001
Volume 10, Issue 1 - Apr 2001
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Mirror Manipulator with Independent Adjustability Using an External Spherical Joint
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 145~154
A new type of modular mirror manipulator with independent adjustability was developed for the EPU6 beamline under construction at the Pohang Accelerator Laboratory. The mirror manipulator was designed so that the angular displacements of roll and pitch rotations do not introduce translational displacements and are independent with each other by positioning the mirror center to the center of a newly devised spherical joint. Manipulating its roll and pitch micrometers, the rotation angles of a dummy mirror were measured at an accuracy of 5
rad using a gravity-referenced inclinometer. While the designed angular resolution was 3.937
, measured angular resolutions were 3.94
for roll rotation and 3.85
for pitch rotation. The effect of roll rotation on pitch angles was measured to be -3.18% and the effect of pitch rotation on roll angles was measured to be -5.21%. As the mirror manipulator was designed with emphases on independent adjustability and standardization, it results in eases of manufacturing, installation and adjustment as well as reductions of development period and design cost of mirror manipulators for various types of mirrors.
Tightening Characteristics of domestic M8 stainless screws
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 155~163
A number of screws are inevitably used for tightening flanges in constructing a vacuum system. A theoretical relation between the axial force and the torque exerted on a screw is easily obtained assuming that the friction force generated on the contacting plane is known, however, in practice the friction is influenced strongly by unknown detailed surface condition. It is difficult to tighten optimally and uniformly the flange seals if the screws commercially available have undefined surface conditions and scattered dimensions, and the axial force produced by the screws can not be expected properly. In this paper a scatter of the axial force over screws and the deviation from an expected one, depending on various fastening conditions, are investigated using a variety of M8, the most popular size for vacuum flanges, domestic stainless screws of hexagonal head and standard thread.
Outgassing characteristics of an aluminum-alloy vacuum chamber
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 164~172
We measured the pumpdown curves of an A5083 vacuum chamber and analyzed the outgassing in terms of desorption energies of water. The outgassing curves follow a ~
behavior before bakeout, which can be described by the first-order desorption of water molecules in the oxide layer. Analysis of the curves reveals that there exist several adsorption sites on the surface for water in the pressure range of ~
Torr. Measurements utilizing the throughput method show that the room temperature outgassing rate is ~
after 24 - h bakeout at
Calibration uncertainty of a capacitance diaphragm gauge
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 173~181
We calibrated a capacitance diaphragm gauge(CDG) of 1,333 Pa range by using ultrasonic interferometer manometer (UIM) that was a national low vacuum standards system. And its uncertainties were evaluated according to International Organization for Standardization(ISO), they were named to A type uncertainty, B type uncertainty, combined standard uncertainty, and expanded uncertainty, We obtained that the combined standard uncertainties were
Pa and the relative uncertainties(combined standard uncertainty/standard pressure) were
Pa for this 1,333 Pa CDG.
films deposited by PECVD using BMDSO and Oxygen
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 182~188
Thin films of
deposited by means of PECVD(plasma enhanced chemical vapor deposition) using HMDSO(hexamethyldisiloxane)/
were characterized. The effects of deposition conditions such as RF power, oxygen flow rate and hydrogen flow rate on the chemical bond structure, atomic composition, surface roughness and wear characteristics of the films were investigated by means of FTIR, XPS, AFM and Hazemeter. The deposition rate of
was greater than 100 nm/min, which is relatively high rate. The XPS results showed that the carbon content in a deposited film was lower than that of previous studies where different organosilicone materials were used. The optimum wear resistance was attained when RF power was 200 Watt and oxygen flow rate was 100 sccm. This study implies that the
system is effective in forming a film with a lower carbon content and good abrasion resistance.
Characteristics of W-TiN Gate Electrode Depending on the Formation of TiN Thin Film
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 189~193
We have characterized physical and electrical properties of W-TiN stacked gate electrode structure with TiN as a diffusion barrier of fluorine. As the
gas ratio increased during sputter deposition, TiN thin films became N-rich, and the resistivity of the films increased. However, the resistivity of W-TiN stacked gate reduced as a result of the crystallization of tungsten with the increase of
gas ratio. On the other hand, tungsten in W-TiN stacked gate structure have the (100)-oriented crystalline structure although TiN films were subjected to annealing at high temperature (600~
). Leakage currents of W-TiN gate MOS capacitors were less than
and also were lowered by the order of 2 compared with those of pure W gate electrode.
A Study on the Optical Properties of Diamod-Like Carbon Film
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 194~200
In this study, the optical properties of diamond-like carbon(DLC) films, which was synthesized by 13.56 MHz rf plasma enhanced chemical vapor deposition system(PECVD), were investigated. We observed the variation of the transmittance and optical band gap with respect to deposition condition. The change of the transmittance and optical band gap of the DLC films were investigated as a function of RF power, working pressure, and additional gas. The optical band gap decreased with the increase of RF power and working pressure. We could verify the bond structures change of DLC films by observing the content of hydrogen using FT-IR spectroscopy. And the addition of hydrogen and nitrogen decreased the optical band gap by the breakage of C-H bond of DLC films during the deposition.
Textures of Fe-Ni Alloy Thin Films Fabricated by Sputtering Method
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 201~206
The evolution of textures in Fe-Ni alloy thin films fabricated by PVD using a sputtering method was investigated with parameters such as deposition time and chemical composition. The textures of the as-deposited films were characterized by fibre-type. In Invar alloy(Fe-36.5 wt%Ni) thin film, the <110>//ND fibre texture as a starting component changed to the <210>//ND fibre texture with increasing deposition time. In Permalloy(Fe-81 wt%Ni) thin film, a mixture of the <221>//ND and <311>//ND fibres developed at the early stage of deposition, and then transformed to the <210>//ND fibre with increasing deposition time. These texture changes were discussed in terms of relationship with the microstructural evolution of the films.
thin films by sol-gel method
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 207~212
In this study, synthesis condition of
thin films which have optimal dielectric characteristics using sol-gel method was determined. Thin films were fabricated using sol which have optimal characteristics and their permittivity was measured. In case of the amount of water for hydrolysis smaller than that for stoichiometry, sol formed clear sol which have normal chain structure. On the contrary, in case of the amount of water for hydrolysis larger than that for stoichiometry, sol formed suspended sol which have cluster structure. The permittivity of thin films increased exponentially around
Structural and electrical properties of ZnO:In films deposited on glass substrates by a spray Pyrolysis method
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 213~218
ZnO and ZnO:In films were deposited on the glass substrates by a spray pyrolysis method. It is found that ZnO films were polycrystalline with the preferred orientation (002) and have a hexagonal structure with lattice constants of a=3.242
. The crystalline structure of ZnO:In films deposited at the In content of 0~6.03 at. % were the same as that of ZnO films, but its lattice constants was slightly larger than those of ZnO films. The relative atomic ratios of metal ion of ZnO:In films were in accordance with those of the spray solution within the experimental error. The minimum resistivity of and the maximum carrier concentration of 19.1
and the maximum carrier concentration of
obtained from the ZnO:In films when In content was 2.76 at. %. The optical transmission of the sample grown at the In content of 3.93 at. % was about 95% in the wavelength between 400 and 800 nm.
Pd/Ge/Ti/pt Ohmic contact to InGaAs for Heterojunction Bipolar Transistors(HBTs)
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 219~224
Pd/Ge/Ti/Pt ohmic contact to n-type InCaAs was investigated. Minimum specific contact resistivity of
was achieved by rapid thermal annealing at
for 10 seconds. This was related to the formation of Pd-Ge compounds and the in-diffusion of Ge atoms to InGaAs surface. However, the specific contact resistivity increased slightly to
in the case of longer annealing time. Superior ohmic contact and non-spiking planar interface between ohmic materials and InGaAs were maintained after annealing at high temperature. Therefore, this thermally stable ohmic contact system is a promising candidate for compound semiconductor devices.
Correction of Secondary ion Mass Spectrometry depth profile distorted by oxygen flooding
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 225~233
Distortion of Secondary Ion Mass Spectrometry(SIMS) depth profile, which is usually observed when the analysis is made using oxygen flooding on the surface of Si with oxide on it, has been corrected. The origin of distortion has been attributed to depth calibration error due to sputter rate difference and concentration calibration error due to relative sensitivity factor(RSF) difference between
and Si layers, In order to correct depth calibration error, artifact in analysis of sodium ion on oxide was used to define the interface in SIMS depth profile and oxide thickness was measured with SEM and XPS. The differences of sputter rate and RSF between two layers have been attributed to volume swelling of Si substrate occurred by oxygen flooding induced oxidation. The corrected SIMS depth profiles showed almost the same results with those obtained without oxygen flooding.
A study on the improvement of TiN diffusion barrier properties using Cu(Mg) alloy
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 234~240
The diffusion barrier properties of TiN by using Cu(Mg) alloy film have been investigated. Cu(Mg) alloy film was deposited on air-exposed TiN film. Upon annealing, interfacial MgO of 100
has been formed due to the reaction of Mg with oxygen existed on the surface of TiN. Combined MgO/TiN structure prevented the interdiffusion of Cu and Si up to
. To improve the adhesion of Cu(Mg) alloy film to the TiN, TiN layer was treated by
plasma, followed by vacuum annealing at
. It was found that increased oxygen on the surface of TiN film by plasma treatment enhanced segregation of Mg toward the interface, resulting in the formation of dense MgO layer. Improved adhesion characteristics have been formed through this treatment. However, increased power of
plasma led to the formation of TiO
and decreased the Mg content to be segregated to the interface, resulting in the decrease in adhesion property. In addition, the deposition of 50
Si on the TiN enhanced the adhesion of Cu(Mg) alloy to TiN without deteriorating the TiN diffusion barrier characteristics.
Changes of the surface hardness and the light transmittance of PET film by ion implantations
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 241~246
Single or dual ion implantations were performed onto the transparent polyethylene terephthalate(PET) sheet, and the surface hardness and the light transmittance in the visual-UV range were examined. Nanoindentation showed that the surface hardness was the highest at about 50 nm depth from the surface and was increased by about 3 times when nitrogen ions were implanted with energy and dose of 90 keV and
respectively. When dual ions such as He+N and N+C ions were implanted into PET, the hardness was increased even more than the case only N ions were implanted. Especially, when PET were implanted with N+C dual ions, the surface hardness of PET increased 5 times more as compared to when implanted with N ions alone. The light at the 550 nm wavelength(visual range) transmitted more than 85%, which is close to that of as-received PET, and at the wavelength below 300 nm(UV range) the rays were absorbed more than 95% as traveling through the sheet. implying that there are processing parameters which the ion implanted PET maintains the transparency and absorbs the UV rays. It can be considered that the increase in the hardness of polymeric materials is attributed to not only cross linking but also forming hard inclusions such as hard C-N compounds, as evidenced by the formation of the highest hardness when both N and C ions are implanted onto PET.
Temperature Dependence of Photoluminescence in
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 247~251
Photoluminescence(PL) were observed from room temperature to 8K on
-implanted silicon-oxide films. The PL intensities are increased from room temperature to 50~80K and decreased below 50K. The blue-shift occurs during the increasing of PL intensity. Also, temperature-dependent PL were measured at peak wavelengths. The first peak is the most sensitive to the measuring temperature. The experimental results are explained by quantum size effect of O rich defects or(and) Si rich defects rather than nanocrystal silicon.
Study on dielectric function of natural ZnSe oxide by spectroscopic ellipsomety
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 252~256
We performed spectroscopic ellipsometry measurement to obtain dielectric function(DF) of ZnSe at room temperature. Proper wet chemical etching procedure was carried out to remove overlayers on top of ZnSe, and our result indicates that the previous reports on the pure DF of ZnSe have inaccurate interpretations. We constructed DF of oxide on ZnSe by using reported DFs of amorphous-Se,
, and voids through Bruggeman effective-medium approximation.
Studies on single electron-hole recombination in InAs/GaAs Quantum dots
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 257~261
InAs/GaAs quantum dots between InGaAs/GaAs superlattices were grown by MBE. The quantum dots size is shown to be very uniform by measuring photoluminescence spectra of quantum dots. Single photon structures based on self-consistent calculation were grown and single photon devices were fabricated by e-beam lithography. The electrical hystereses of I-V curves for single Photon devices would result from single electron-hole recombination, where the resonant-tunneling voltages of electron and hole are different.
Electro-magnetic properties of GaAs/AlGaAs quantum wires
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 262~266
We have presented the electrical properties of the quantum wire fabricated by split gate on GaAs/AlGaAs heterostructures by using the Shubnikov de Haas oscillation and quantum Hall effect measurements. We observed the 1D properties of the sample as increasing gate voltage. The misfit between quantum Hall plateau and minima in Shubnikov do Haas oscillations are interpreted as Landauer-B
tikker formula based on the edge state transport.port.
Cr, Ni and Cu removal from Si wafer by remote plasma-excited hydrogen
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 267~274
Removal of Cr, Ni and Cu impurities on Si surfaces using remote plasma-excited hydrogen was investigated. Si surfaces were contaminated intentionally by acetone with low purity. To determine the optimum process condition, remote plasma-excited hydrogen cleaning was conducted for various rf-powers and plasma exposure times. After remote plasma-excited hydrogen cleaning, Si surfaces were analyzed by Total X-ray Reflection Fluorescence(TXRF), Surface Photovoltage(SPV) and Atomic Forece Microscope(AFM). The concentrations of Cr, Ni and Cu impurities were reduced and the minority carrier lifetime increased after remote plasma-excited hydrogen. Also RMS roughness decreased by more than 30% after remote plasma-excited hydrogen cleaning. AFM analysis results also show that remote plasma-excited hydrogen cleaning causes no damage to the Si surface. TXRF analysis results show that remote plasma-excited hydrogen cleaning is effective in eliminating metallic impurities from Si surface only if it is performed under an optimum process conditions. The removal mechanism of the Cr, Ni and Cu impurities using remote plasma-excited hydrogen treatments is proposed to be the lift-off during removal of underlying chemical oxides.
Model of Particle Growth in Silane Plasma Reactor for Semiconductor Fabrication
Journal of the Korean Vacuum Society, volume 10, issue 2, 2001, Pages 275~281
We used the discrete-sectional model to analyze the particle growth by coagulation of particles in silane plasma reactor, considering the Gaussian distribution function for particle charges. The effects of process conditions such as monomer size and mass generation rate of monomers on particle growth in plasma reactor were analyzed theoretically/ Based on the Gaussian distribution function of particle charges, the large particles of more than 40 nm in size are almost found to be charged negatively, but some fractions of small, tiny particles are in neutral state or even charged positively. As the particle size and surface area increase with time by particle coagulation, the number of charges per particle increases with time. As the large particles are generated by particle coagulation, the particle size distribution become bimodal. The results of discrete-sectional model for the particle growth in silane plasma reactor were in close agreement with the experimental results by Shiratani et al.  for the same plasma conditions. We believe the model equations for the particle charge distribution and coagulation between particles can be applied to understand the nano-sized particle growth in plasma reactor.