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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
Editor in Chief :
Volume & Issues
Volume 8, Issue 4B - Dec 1999
Volume 8, Issue 4A - Nov 1999
Volume 8, Issue 3B - Aug 1999
Volume 8, Issue 3A - Aug 1999
Volume 8, Issue 2 - Mar 1999
Volume 8, Issue 1 - Feb 1999
Selecting the target year
Vacuum properties of CFC (carbon fiber composits)
Journal of the Korean Vacuum Society, volume 8, issue 4B, 1999, Pages 497~506
Carbon has been widely used for the material of plasma facing components in fusion experiment devices like a tokamak, because carbon has good thermal and mechanical properties. However carbon gas a relatively high ougassing rate. Therefore the amount and the surface area of the carbon material used in the vessel will determine the background pressure of the vacuum vessel. In this experiment influences of carbon on the vacuum performance was investigated by measuring chamber pressure, ougassing rater and gas spectrum of carbon fiber composite (CFC) samples in various situations, pumping out, chamber baking, carbon heating (250~
), exposure to atmosphere for maintenance of in-vessel components, etc., occurring routinely during tokamak operations.
Oxygen detection of sensor cells based on YSZ (Yttria-Stabilized Zirconia) thin films
Journal of the Korean Vacuum Society, volume 8, issue 4B, 1999, Pages 507~513
8mol%-yttria-stabilized zirconia(YSZ) thin films as oxygen ion conductor were deposited by rf-magnetron sputtering, and the oxygen gas sensors with the structure of
substrate/Ni-NiO mixed reference layer/Pt/YSZ/Pt were fabricated and their oxygen sensing properties were investigated. The steady-state electro-motive force (EMF) values were measured as a function of oxygen partial pressure (
Pa) and operating temperature (
). The fabricated YSZ oxygen sensor showed the best oxygen sensing properties at 50
. However, oxygen sensing properties were very low at the temperature lower than 30
due to the lack of oxygen ion mobility and at the temperature higher than
due 새 intermixing of materials between the layers. Especially, the YSZ sensor operating at
and oxygen partial pressure above
Pa showed the oxygen sensing properties close to the values predicted by ideal Nernst equation.
Ion beam induced surface modifications of sapphire and gold film deposition: studies on the adhesion enhancement and mechanisms
Journal of the Korean Vacuum Society, volume 8, issue 4B, 1999, Pages 514~518
Gold (Au) is not supposed to react with sapphire(single crystalline
Epitaxial thickness during low-temperature Si(001) growth: effect of substrate vicinality
N.-E. Lee ;
Journal of the Korean Vacuum Society, volume 8, issue 4B, 1999, Pages 519~523
of Si films grown at the substrate temperature
by ultra-high vacuum ion-beam sputter deposition onto nominally-singular, -miscut Si(001) was measured.
values of films grown on vicinal Si(001) substrates were decreases compared to those of films grown on nominally-singular Si(001). Evolution of surface roughness measured by atomic force microscopy of films grown at
showed that the increases step density in vicinal substrates increases the tendency toward unstable growth resulting in larger surface roughness, which in turn decreases te.
Adding effect of ammonia solution on deposition of diamond phase carbon thin films by electrolysis method
Journal of the Korean Vacuum Society, volume 8, issue 4B, 1999, Pages 524~529
We deposited diamond phase carbon thin films on Si substrate by the electrolysis of methanol solution. A little amount of ammonia solution was added to increase the current density of the electrolyte. We analyzed films by XRD and SEM. The chemical change of electrolyte during the electrolysis process was characterized by FTIR. We obtained better quality diamond phase carbon films at a lower applying boltage(300V) and temperature (
) by adding ammonia solution to methanol electrolyte. Diamond (111), (220), (311) peaks were shown distinctively in XRD graph. Addition of ammonia solution resulted in lowering the applying bias voltage to 300V and the substrate temperature to
still maintaining a high current density at 80mA/
, which prohibited a great loss of solution from vaporization. Possible change of chemical reaction due to the addition of ammonia solution was also discussed.
Fabrication and evaluation of NSOM apparatus
Journal of the Korean Vacuum Society, volume 8, issue 4B, 1999, Pages 530~535
W made a near-field optical microscope(NSOM) apparatus and evaluated it. To control the distance between a tip and a sample, we used a piezoelectric translator and a He-Ne laser, and consequently obtained the spatial resolution better than 100nm. For the semiconductor spectroscopic applications, we performed photoluminescence and photocurrent experiments on the GaAs/AlGaAs MQWs samples. In the case of PL experiment, we obtained the low signal to nose ration due to the extremely small power of a light source passing through the nanometric optical fiber tip. However photocurrent experiment shows a hundred times better signal to noise than that of PL experiment. This suggests that photocurrent experiment using NSOM have the possibility to provide the spatial resolution better than 10nm.
Fabrication and its characteristics of
self-align gate GaAs LDD MESFET
Journal of the Korean Vacuum Society, volume 8, issue 4B, 1999, Pages 536~540
We have developed a refractory WNx self-aligned gate GaAs metal-semiconductor field-effect transistor(MESFET) using
side-wall process. The MESFET hasa fully ion-implanted, planar, symmetric self-alignment structure, and it is quite suitable for integration. The uniform trans-conductance of 354nS/mm up to Vgs=+0.6V and the saturation current of 171mA/mm were obtained. As high as 43GHz of cut-off frequency hs been realized without any de-embedding of parasitic effects. The refractory WNx self-aligned gate GaAs MESFET technology is one of the most promising candidates for realizing linear power amplifier ICs and multifunction monolithic ICs for use in the digital mobile communication systems such as hand-held phone(HHP), personal communication system (PCS) and wireless local loop(WLL).
Reactive ion etching of InP using
inductively coupled plasma
Journal of the Korean Vacuum Society, volume 8, issue 4B, 1999, Pages 541~547
Reactive ion etching process for InP using BCl3/O2/Ar high density inductively coupled plasma was investigated. The experimental design method proposed by the Taguchi was utilized to cover the whole parameter range while maintaining reasonable number of actual experiments. Results showed that the ICP power and the chamber pressure were the two dominant parameters affectsing etch results. It was also observed that the etch rate decreased and the surface roughness improved as the ICP power and the bias voltage increased and as the chamber pressure decreased. The Addition of oxygen to the gas mixture drastically improved surface roughness by suppressing the formation of the surface reaction product. The optimum condition was ICP power 600W, bias voltage -100V, 10%
, 6mTorr, and
, resulting in about 0.15
etch rate with smooth surfaces and vertical mesa sidewalls Also, the maximum etch rate of abut 4.5
/min was obtained at the condition of ICP power 800W, bias voltage -150V, 15%
, 8mTorr and
Design of the vacuum pumping system for the KSTAR NBI device
Journal of the Korean Vacuum Society, volume 8, issue 4B, 1999, Pages 548~555
The NBI (Neutral BGeam Injection) System for the Korea Superconducting Tokamak Advanced Research (KSTAR) is composed of ion sources, neutralizers, bending magnets, ion dumps, and calorimeter. The vacuum chamber, in which all of the beam line components are enclosed, is composed of differential pumping system for the effective transfer of the neutral beams. The needed pumping speeds of each of the divided vacuum chamber and the optimized gas flow rate ot the neutralizer were calculated with the help of the particle balance equations. The minimum gas flow rate to the ion sources for producing needed beam current (120kV, 65A, 78MW), the pressure distributions in the vacuum chamber for minimizing re-ionization loss, and the beam loss rate on the beam line components were used as the input in the calculation. Also the scenario for short pulse operation was determined by analysing the time dependent equations. It showed that beam extraction during less than 0.5 sec could be made only with TMP.
An Analysis on the KSTAR neutral beam injection line
Journal of the Korean Vacuum Society, volume 8, issue 4B, 1999, Pages 556~564
The analysis on heat fluxed on and transmission efficiencies by the collimators of neutral beam injection lines in KSTAR tokamak device has been carried out. And a mathematical model describing non-Gaussian beam distribution profile has been established. A neutral beam injection device is composed of 3 separate ion sources and corresponding beam transport lines, which deal with 7.8 MW of beam power, respectively. The divergence angles of ion beam are
, in vertical and horizontal directions, respectively. The maximum normal heat load on source exit scraper is 9.1 kW/
and net beam transmission efficiency is ~28%. The effect of misalignment of ion source and scrapers on the scraper heat load and beam transmission also has been analyzed.
Etch characteristics of ITO(Indium Tin Oxide ) using inductively coupled Ar/
Journal of the Korean Vacuum Society, volume 8, issue 4B, 1999, Pages 565~571
In this study, high-density plasma etching characteristics of ITO(indium tin oxide) films used for transparent electrode in dispaly devices were investigated. Plasma diagnostic and surface analysis tools were used to understand etch reaction mechanism. The etch rate of ITO was increased by the increase of reactive radicals such as H and
with the addition of moderate amount of
to Ar. However, the addition of excess amount of
decreased possibly due to the increased polymer formation on the ITO surface being etched. The increase of source power and bias boltage increased ITO etch rates but it decreased selectivities over under-layers
. The increase of working pressure up to 20mTorr also increased ITO etch rates, however the further increased of the pressure decreased ITO etch rates. From the analysis of XPS, a peak related to the polymer of hydrocarbon was observed on the etched ITO surface especially for high
conditions and it appears to affect ITO etch rates.