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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 12, Issue 4 - Dec 2003
Volume 12, Issue S1 - Oct 2003
Volume 12, Issue 3 - Sep 2003
Volume 12, Issue 2 - Jun 2003
Volume 12, Issue 1 - Mar 2003
Selecting the target year
Gas desorption species and quantity from the hot cathode ionization gauges
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 201~206
A residual gas analyzer was used to study the outgassing behavior of stainless steel 304 chamber as a function of bake-out temperature up to
and to identify the gas species evolved during turn on and degassing of the three different types of hot cathode ionization gauges. It was found that
, CO, and
were the dominent outgassing species in the vacuum chamber during bake-out but finally
and CO(mass 28) persisted at room temperature. Dominant outgassing species were also
while fuming on the ionizations and then
and CO were found to be the main species degassed gauges. It was appeared that the outgassing species and quantity were not agreed to the three different types of hot cathode ionization gauges.
A study on the system automation of medium-vacuum standard
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 207~213
We have developed the hardware and software for automation of the national medium vacuum standard. The automation is necessary to control and monitor the complex system consists of several vacuum chambers, pumping systems, vacuum gauges, thermometers, and valves. By using the automation program, we have measured volume ratios of the system and performed calibration of a capacitance diaphragm gauge in order to evaluate the system.
A Study of the Crystallographic Characteristic of ZnO Thin Film Grown on ZnO Buffer Layer
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 214~217
In this study, we prepared ZnO thin film on
/Si substrate by FTS (Facing Targets Sputtering) apparatus which can reduce damage on the thin film because the bombardment of high-energy Particles such as
-electron can be restrained. And, properties of thin filnl grown with ZnO buffer-layer which can be suppress initial growth layer was investigated. The crystalline and the c-axis preferred orientation of ZnO thin film was also investigated by XRD. As a result, we noticed that the ZnO thin film has a good crystallographic characteristic at thickness of ZnO buffer layer 10, 20 nm and working pressure 1 mTorr.
Pd/Si-based Emitter Ohmic Contacts for AlGaAs/GaAs HBTs
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 218~227
Pd/Si/Ti/Pt and Pd/Si/Pd/Ti/Au ohmic contacts to n-type InCaAs were investigated for applications to AlGaAs/GaAs HBT emitter ohmic contacts. In the Pd/Si/Ti/Pt ohmic contact, as-deposited contact showed non-ohmic behavior, and high specific contact resistivity of
was achieved by rapid thermal annealing at
/10 sec. However, the specific contact resistivity decreased remarkably to
by annealing at
/10sec. In the Pd/Si/Pd/Ti/Au ohmic contact, minimum specific contact resistivity of
was achieved by annealing at
/20sec. In both ohmic contacts, low contact resistivity and non-spiking planar interface between ohmic materials and InGaAs were maintained. Therefore, these thermally stable ohmic contact systems are promising candidates for compound semiconductor devices. RF performance of the AlGaAs/GaAs HBT was also examined by employing the Pd/Si/Ti/Pt and Pd/Si/Pd/Ti/Au systems as emitter ohmic contacts. Cutoff frequencies were 63.9 ㎓ and 74.4 ㎓, respectively, and maximum oscillation frequencies were 50.1 ㎓ and 52.5 ㎓, respectively. It shows very successful high frequency operations.
Study on the velocity of gadolinium atomic vapor produced by electron beam heating
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 228~234
The velocity of gadolinium(Gd) atomic vapor vaporized by an electron beam was measured by a microbalance. The velocity of about 900 ㎧ was obtained at an evaporation surface temperature of 2400-2500 K. The measured value was approximately 100 ㎧ faster than the maximum velocity of an ideal monatomic gas in an adiabatic expansion. This phenomenon can be explained that the internal energy of Gd atoms populated in higher excited levels at the high temperature should be convened to kinetic energy during adiabatic expansion. The calculated velocity agrees with the measured one when 100 excited energy levels are included in an enthalpy term for the velocity calculation. The characteristics of vapor flow as a function of heated surface temperature are also reported.
A study of violet LED chips and white LED lamps
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 235~238
Conventional LED displays use pixels which consist of red, green and blue LEDs of different operation voltages and degradation characteristics. Thus, the circuits are complicated and the display of each color changes independently with the operated time. In order to solve these drawbacks, an LED chip of a short wavelength and an LED lamp with the mixture of red, green, blue fluorescencers and epoxy on the LED chip were studied. The fluorescencers are excited by the light of the LED chip. The LED chip has an active layer of InGaN, a peak wavelength of 408 nm, a FWHM of 13 nm and the CIE index of (0.198, 0.087). White LED lamps were obtained and the CIE index change was observed with the change of the epoxy amount added to the fluorescencers.
The reliability physics of SiGe hetero-junction bipolar transistors
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 239~250
The reliability degradation phenomena in the SiGe hetero-junction bipolar transistor (HBT) are investigated in this review. In the case of the SiGe HBT the decrease of the current gain, the degradation of the AC characteristics, and the offset voltage are frequently observed, which are attributed to the emitter-base reverse bias voltage stress, the transient enhanced diffusion, and the deterioration of the base-collector junction due to the fluctuation in fabrication process, respectively. The reverse-bias stress on the emitter-base junction causes the recombination current to rise, increasing the base current and degrading the current gain, because hot carriers formed by the high electric field at the junction periphery generate charged traps at the silicon-oxide interface and within the oxide region. Because of the enhanced diffusion of the dopants in the intrinsic base induced by the extrinsic base implantation, the shorter distance between the emitter-base junction and the extrinsic base than a critical measure leads to the reduction of the cut-off frequency (
) of the device. If the energy of the extrinsic base implantation is insufficient, the turn-on voltage of the collector-base junction becomes low, in the result, the offset voltage appears on the current-voltage curve.
Effects of growth temperatures on properties of InAlAs epilayers grown on InP substrate by molecular beam epitaxy
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 251~256
Indium aluminum arsenide(InAlAs) was grown by molecular beam epitaxy on (001) indium phosphide (InP) substrate and the effects of growth temperature on the properties of epitaxial layers were studied. In the temperature range of 370-
, we observed that the surface morphology, optical quality and structural quality of InAlAs epilayers were improved as growth temperature increased. However, the InAlAs epilavers grown at
have the bad surface morphology and show the same trends as structural and epical quality. As a result of these measurements, it is suggested that the InAlAs epilayers of very good properties can be grown at
The structure and optical properties of n-type and p-type porous silicon
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 257~262
The structure and optical properties of n-type and p-type porous silicon (PS) prepared by the chemical etching in the light and the dark, respectively, are reported in this paper. Microstructural features of the samples are mainly investigated by SEM, AFM XRDGI techniques. Also, their optical properties are investigated by photoluminescence (PL) and Fourier transform infrared absorption measurements. In the n-type PS, the room temperature photoluminescence is observed in a visible range from 500 nm to 650 nm in contrast to that in the blue region (400∼650 nm) in p-type PS. Further, semi-transparent Cu films in thickness range of ∼40 nm are deposited by rf-magnetron sputtering on PS to investigate the I-V characteristics of the samples.
The characteristics of silicon nitride thin films prepared by atomic layer deposition with batch type reactor
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 263~268
Precise thickness control and excellent properties of silicon nitride thin films are essential for the next-generation semiconductor and display devices. In this study, silicon nitride thin films were deposited by batch-type atomic layer deposition (ALD) method using
as the precursors at temperatures ranging from 500 to
. Thin film deposition using a batch-type ALD reactor was a layer-by-layer atomic growth by self-limiting surface reactions, and the thickness of the deposited film can be controlled by the number of deposition cycles. The silicon nitride thin films deposited by ALD method exhibited composition, refractive index and wet etch rate similar with those of the thin films deposited by low-pressure chemical vapor deposition method at
. The addition of pyridine mixed with precursors increased deposition rate by 50%, however, the films deposited with pyridine was readily oxidized owing to its unstable structure, which is unsuitable for the application to semiconductor or display devices.
ZnNiO thin films deposited by r.f. magnetron sputtering method
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 269~274
The electrical, optical and structural properties of ZnNiO thin _ films deposited on Si substrates using rf-magnetron sputtering method have been investigated before and after the thermal annealing processes. The crystallinity of the ZnNiO thin film become degraded with increasing the Ni contents. This is mainly because the lattice of the thin film was expanded due to the oxygen-deficient conditions. Concerning the electrical properties of the thin film, the carrier concentration increases (
) and Hall mobility decreases (36.3
/Vㆍs) with higher doping concentration of Ni. However, the carrier concentration and Hall mobility became low (
and high (209.6
/Vㆍs), respectively, after the thermal annealing process at
. We also observed a strong luminescene center peaking at 546 nm in photoluminescence spectra, which was caused by a deep level center in the ZnO band gap with oxygen deficient ZnNiO structure.
Optical properties of epitaxial
luminescent thin films depending on crystallinity
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 275~280
luminescent thin films have been grout on Si(III) substrates using ionized Cluster Beam Deposition (ICBD). After the film growing, they were implanted and post annealed to change the crystal structure. The initial growth stage was monitored by using in-situ Reflection High Energy Electron Diffraction (RHEED). The formed crystal structure was identified with X-ray diffraction (XRD) technique and Fourier transform infrared (FT-R) spectroscopy. The electronic states variations were investigated by Near Edge X-ray Absorption Fine Structure (NEXAFS). Photoluminescence (PL), Cathodoluminescence (CL). and Vacuum ultraviolet (VUV) spectrum were used for examining the optical properties. We report the optical property changes depending on crystal structure and the electronic states.
Molecular dynamics study of silicon nanotubes
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 281~287
We have performed classical molecular dynamics simulations for hypothetical silicon nanotubes using the Tersoff potential. Our investigation presented a systematic study about the thermal behavior of hypothetical silicon nanotubes and showed the difficulty in Producing silicon nanotubes or graphitelike sheets. Through the investigations on the structure and properties of a double-wall silicon nanotube, we concluded that quasi-one dimensional structures consisting of silicon atoms become nanowires or multi wall nanotubes rather than single wall nanotubes in order to minimize the number of
Nano-master fabrication for photonic crystal waveguides
Journal of the Korean Vacuum Society, volume 12, issue 4, 2003, Pages 288~292
The fabrication of silicon nano-master with pillar structures using E-beam lithography and ICP etching was investigated for application of 2-dimensional polymer photonic crystal waveguides with air hole structures. Pillar structures with square, hexagon, dodecagon and circle were successfully fabricated. The diameters and structures of fabricated pillars were measured by CD-SEM and SPM-AFM. It was found that the optimal dose for complete circle pillar structures was 432