• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.6
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• pp.412-417
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• 2000

High electric field stressed trap distributions were investigated in the thin silicon oxide of polycrystalline silicon gate metal oxide semiconductor capacitors. The transient currents associated with the off time of stressed voltage were used to measure the density and distribution of high voltage stress induced traps. The transient currents were due to the discharging of traps generated by high stress voltage in the silicon oxides. The trap distributions were relatively uniform near both cathode and anode interface in polycrystalline silicon gate metal oxide semiconductor devices. The stress generated trap distributions were relatively uniform the order of $10^{11}$~$10^{12}$ [states/eV/$\textrm{cm}^2$] after a stress. The trap densities at the oxide silicon interface after high stress voltages were in the $10^{10}$~$10^{13}$ [states/eV/$\textrm{cm}^2$]. It was appeared that the transient current that flowed when the stress voltages were applied to the oxide was caused by carriers tunneling through the silicon oxide by the high voltage stress generated traps.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.2
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• pp.83-88
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• 2005

The interface-states between the top silicon layer and buried oxide layer of nano-SOI substrate were developed. Also, the effects of thermal treatment processes on the interface-state distributions were investigated for the first time by using pseudo-MOSFETs. We found that the interface-state distributions were strongly influenced by the thermal treatment processes. The interface-states were generated by the rapid thermal annealing (RTA) process. Increasing the RTA temperature over $800^{\circ}C$, the interface-state density considerably increased. Especially, a peak of interface-states distribution that contributes a hump phenomenon of subthreshold curve in the inversion mode operation of pseudo-MOSFETs was observed at the conduction band side of the energy gap, hut it was not observed in the accumulation mode operation. On the other hand, the increased interface-state density by the RTA process was effectively reduced by the relatively low temperature annealing process in a conventional thermal annealing (CTA) process.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.2
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• pp.82-87
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• 2007

The electrical properties of metallic junction diodes and metallic source/drain (S/D) Schottky barrier metal-oxide-semiconductor field-effect transistor (SB-MOSFET) were simulated. By using the abrupt metallic junction at the S/D region, the short-channel effects in nano-scaled MOSFET devices can be effectively suppressed. Particularly, the effects of trap states at the metal-silicide/silicon interface of S/D junction were simulated by taking into account the tail distributions and the Gaussian distributions at the silicon band edge and at the silicon midgap, respectively. As a result of device simulation, the reduction of interfacial trap states with Gaussian distribution is more important than that of interfacial trap states with tail distribution for improving the metallic junction diodes and SB-MOSFET. It is that a forming gas annealing after silicide formation significantly improved the electrical properties of metallic junction devices.

• Journal of Magnetics
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• v.12 no.2
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• pp.68-71
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• 2007

Even a pure bulk Fe has a complicated magnetic phase and its magnetism is still needed to be clarified. In this study we investigated the magnetism of bcc and fcc bulk Fe with total energy calculations as functions of atomic volume. The full-potential linearized augmented plane wave method was adopted within a generalized gradient approximation. The ground state of bulk Fe is confirmed to be of ferromagnetic (FM) bcc. For fcc structured Fe an antiferromagnetic (AFM) state is more stable compared to FM states which exist as low spin and high spin states. The stable AFM states were found to accompany a tetragonal distortion, while the FM states remained in a cubic symmetry. At an expanded lattice constant a high spin FM state was calculated to be able to be stabilized with significant enhanced magnetic moment compared to the value of the ground state, bcc FM.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.385-391
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• 2011

The time-dependent density functional theory (TDDFT) method has been carried out to investigate the excitedstate hydrogen-bonding dynamics of phenol-$(H_2O)_2$ complex. The geometric structures and infrared (IR) spectra in ground state and different electronically excited states ($S_1$ and $T_1$) of the hydrogen-bonded complex have been calculated using the density functional theory (DFT) and TDDFT method. A ring of three hydrogen bonds is formed between phenol and two water molecules. We have demonstrated that the intermolecular hydrogen bond $O_1-H_2{\cdots}O_3-H$ of the three hydrogen bonds is strengthened in $S_1$ and $T_1$ states. In contrast, the hydrogen bond $O_5-H_6{\cdots}O_1-H$ is weakened in $S_1$ and $T_1$ states. These results are obtained by theoretically monitoring the changes of the bond lengths of the hydrogen bonds and hydrogen-bonding groups in different electronic states. The hydrogen bond $O_1-H_2{\cdots}O_3-H$ strengthening in both the $S_1$ and $T_1$ states is confirmed by the calculated stretching vibrational mode of O-H (phenol) being red-shifted upon photoexcitation. The hydrogen bond strengthening and weakening behavior in electronically excited states may exist in other ring structures of phenol-$(H_2O)_n$.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.5
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• pp.593-598
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• 2015

Non-linear cellular automata is difficult to analyze mathematically than linear cellular automata. So it is difficult to identify reachable states and attractors of nongroup non-linear cellular automata than nongroup linear cellular automata. In this paper, we propose a new reachable table to overcome these problems. We can see the next state for all the states of the non-linear cellular automata by the proposed reachable table. In addition, we can identify reachable states and attractors by the reachable table.

• Electrical & Electronic Materials
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• v.9 no.3
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• pp.291-297
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• 1996

The surface properties of AI(Si, Cu) alloy film after plasma etching using the chemistries of chlorinated and fluorinated gases with varying the etching time have been investigated using X-ray Photoelectron Spectroscopy. Impurities of C, Cl, F and O etc are observed on the etched AI(Si, Cu) films. After 95% etching, aluminum and silicon show metallic states and oxidized (partially chlorinated) states, copper shows Cu metallic states and Cu-Cl$_{x}$(x$_{x}$ (x$_{x}$ (1

• ETRI Journal
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• v.24 no.2
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• pp.109-116
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• 2002

We propose a novel very short (< $300{\mu}m$) vertical directional coupler switch with high extinction ratios larger than 30 dB. The device consists of a switching operation induced section (SOIS), an extinction ratio adjusted section (ERAS), and an extinction ratio enhanced section (ERES). These are achieved by changing the refractive index of one core. The switching operation is induced by changing the refractive index of one core in the SOIS. The improvement of extinction ratios larger than 30 dB for both the cross and bar states is made by controlling the asymmetry of the refractive indices of both cores in the ERES. Through the ERAS, different extinction ratios between the cross and bar states at the end of the SOIS are changed to the same value. For this reason, the optimum asymmetry of the refractive indices of the cores for the maximum extinction ratios and the lengths of ERES are the same for cross and bar states. Design guidelines for high extinction ratios with large tolerances are presented.

• Journal of Magnetics
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• v.8 no.4
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• pp.149-152
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• 2003

The electronic structure of Mn12-Ac molecular magnet has been investigated using synchrotron radiation. The valence-band photoemission spectroscopy (PES) measurement reveals that Mn 3d states are located near the top of the valence band. The trend in the measured valence-band PES spectra is found to be consistent with that in the calculated local density of states. The Mn 2p x-ray absorption spectroscopy (XAS) measurement provides evidence for the Mn$^{3+}$-Mn$^{4+}$ mixed-valent states.

• Journal of Sensor Science and Technology
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• v.5 no.6
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• pp.60-67
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• 1996

The interfacial electrical properties of InSb MIS structure with low temperature remote PECVD $SiO_{2}$ have been characterized. The interlace-state density at mid-bandgap of the MIS structure was about $1{\sim}2{\times}10^{11}\;cm^{-2}eV^{-1}$, when the $SiO_{2}$ film was deposited at $105^{\circ}C$. However, large amount of interlace states and trap states were observed in the MIS structure fabricated at temperatures above $105^{\circ}C$. The time constant of $10^{-4}{\sim}10^{-5}\;sec$ of interface states was extracted from G- V measurement. As the deposition temperature increased, the hysteresis of C- V curves were increased due to the high trap density.