• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.3
• /
• pp.6-21
• /
• 2008

We have investigated the effect of the forward and reverse ESD pulse accumulation on the development of the oxide VCSEL's electrical and optical characteristics. The forward ESD-induced degradation is complicated, showing three degradation phases with increasing ESD voltage while the reverse ESD-induced degradation is divided by a sudden distinctive change in elecorl-optical characteristics. By comparing the measured L-I-V characteristics and their derivatives with the fitted characteristics using an equivalent circuit model as well as the large signal circuit model, the development of the oxide VCSEL's electro-optical characteristics under forward and reverse ESD conditions has been fully understood.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.135-135
• /
• 2015

Tubes are of extreme importance in industries as for fluid channels or wave guides. Furthermore, some weapon systems such as cannons use the tubes as gun barrels. To increase the service life of such tubes, a protective coating must be applied to the tubes' inner surface. However, the coating methods applicable to the inner surface of the tubes are very limited due to the geometrical restriction. A small-diameter cylindrical magnetron sputtering gun can be used to deposit coating layers on the inner surface of the large-bore tubes. However, for small-bore tubes with the inner diameter of one inch (~25 mm), the magnetron sputtering method can hardly be accommodated due to the space limitation for permanent magnet assembly. In this study, a new approach to coat the inner surface of small-bore tubes with the inside diameter of one inch was developed. Instead of using permanent magnets for magnetron operation, an external electro-magnet assembly was adopted around the tube to confine the plasma and to sustain the discharge. The electro-magnet was operated in pulse mode to provide the strong axial magnetic field for the magnetron operation, which was synchronized with the negative high-voltage pulse applied to the water-cooled coaxial sputtering target installed inside the tube. By moving the electro-magnet assembly along the tube's axial direction, the inner surface of the tube could be uniformly coated. The inner-surface coating system in this study used the tube itself as the vacuum chamber. The SS-304 tube's inner diameter was 22 mm and the length was ~1 m. A water-cooled Cu tube (sputtering target) of the outer diameter of 12 mm was installed inside of the SS tube (substrate) at the axial position. The 50 mm-long electro-magnet assembly was fed by a current pulse of 250 A at the frequency and pulse width of 100 Hz and 100 usec, respectively. The calculated axial magnetic field strength at the center was ~0.6 Tesla. The central Cu tube was synchronously driven by a HiPIMS power supply at the same frequency of 100 Hz as the electro-magnet and the applied pulse voltage was -1200 V with a pulse width of 500 usec. At 150 mTorr of Ar pressure, the Cu deposition rate of ~10 nm/min could be obtained. In this talk, a new method to sputter coat the inner surface of small-bore tubes would be presented and discussed, which might have broad industrial and military application areas.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.6 no.4
• /
• pp.72-79
• /
• 1997

A study is a experiment which is figure out to optimum discharge cutting condition of the surface roughness, electronic discharging speed and electrode wear ration with Ton , Toff and V(voltage) as an input condition according to the current(Ip) in an electric spark machine : 1) Electrode is utilized Cu and Graphite. 2) Work piece is used the material of carbon steel. The condition of experiment is : 1) Current is varied 0.7(A) to 50(A) and the time of electric discharging to work piece in each time is 30(min) to 60(min). 2) After the upper side of work piece was measured in radius(5$\mu$m) of stylus analyzed the surface roughness to ade the table and graph of Rmax by yielding data. 3) Electro wear ratio is : \circled1Cooper was measured ex-machining and post-machining by the electronic balance. \circled2The ex-machining of graphite measured by it, the post-machining was found the data from volume $\times$specific gravity and analyzed to made its table and graph on ground the data. 4) In order to keep the accuracy of voltage affected to the work piece was equipped with the A.V. R and the memory scope was sticked to the electric spark machine. 5) In order to preserve the precision of current, to get rid of the noise occured by internal resistance of electric spark machine and to force injecting for the discharge fluid , it made the fixed table for a work piece to minimize the work error by means of one's failure during the electric discharging.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.2
• /
• pp.106-112
• /
• 2010

In order to compete with other flat display devices such as Liquid Crystal Displays (LCDs) and organic light emitting diodes (OLEDs), Plasma Display Panels (PDPs) require to have high performances like high image quality, low power consumption and high speed driving. In this paper, Fe doped MgO protective layer was introduced for higher performance. Both the surface characteristics of the deposited thin films and the electro-optical properties of 4 inch test panels were investigated. It has been demonstrated experimentally that ac PDP with Fe doped MgO protective layer has lower discharge voltage than that of undoped MgO film, which corresponds to measured secondary electron emission coefficients. The crystallinity and surface roughness of thin films were determined by XRD patterns and AFM images. In addition, ac PDP with Fe doped MgO protective layer has improved address discharge time lag for high speed driving.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.409-409
• /
• 2011

All solid-state thin film lithium batteries have many applications in miniaturized devices because of lightweight, long-life, low self-discharge and high energy density. The research of cathode materials for thin film lithium batteries that provide high energy density at fast discharge rates is important to meet the demands for high-power applications. Among cathode materials, lithium manganese oxide materials as spinel-based compounds have been reported to possess specific advantages of high electrochemical potential, high abundant, low cost, and low toxicity. However, the lithium manganese oxide has problem of capacity fade which caused by dissolution of Mn ions during intercalation reaction and phase instability. For this problem, many studies on effect of various transition metals have been reported. In the preliminary study, the Sn-substituted LiMn2O4 thin films prepared by pulsed laser deposition have shown the improvement in discharge capacity and cycleability. In this study, the thin films of LiMn2O4 and LiSn0.0125Mn1.975O4 prepared by RF magnetron sputtering were studied with effect of deposition parameters on the phase, surface morphology and electrochemical property. And, all solid-state thin film batteries comprised of a lithium anode, lithium phosphorus oxy-nitride (LiPON) solid electrolyte and LiMn2O4-based cathode were fabricated, and the electrochemical property was investigated.

• Journal of Institute of Control, Robotics and Systems
• /
• v.15 no.6
• /
• pp.567-572
• /
• 2009

The underwater launch system using an ATP consists of five parts: compressor tank, proportional flow control servo valve, expulsion spool valve, air turbine pump, and discharge tube. The purpose of this study is to develop an underwater launch system using an ATP and to verify the validity of the system. The proportional flow control servo valve is modeled as a 2nd order transfer function. The projectile is ejected by pressurized water through the air turbine pump, which is controlled by expulsion valve. The mathematical model is derived to estimate the dynamic characteristics of the system, and the important design parameters are derived by using simulations. The computer simulation results show the dynamic characteristics and the possibility of control for underwater launch system.

• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.731-734
• /
• 2005

In this study, the design of advanced LVDS(Low Voltage Differential Signaling) I/O interface circuit with new structural low triggering ESD (Electro-Static Discharge) protection circuit was investigated. Due to the differential transmission technique and low power consumption at the same time. Maximum transmission data ratio of designed LVDS transmitter was simulated to 5Gbps. And Zener Triggered SCR devices to protect the ESD phenomenon were designed. This structure reduces the trigger voltage by making the zener junction between the lateral PNP and base of lateral NPN in SCR structure. The triggering voltage was simulated to 5.8V. Finally, we performed the layout high speed I/O interface circuit with the low triggered ESD protection device in one-chip.

• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.805-808
• /
• 2005

In this study, the design of advanced LVDS(Low Voltage Differential Signaling) I/O interface circuit with new structural low triggering ESD(Electro-Static Discharge) protection circuit was investigated. Due to the differential transmission technique and low power consumption at same time. maximum transmission data ratio of designed LVDS transmitter was simulated to 5Gbps, Also, the LIGCSCR(Latch-up Immune Gate Coupled SCR)was designed. It consists of PLVTSCR (P-type Low Voltage Trigger SCR), control NMOS and RC network. The triggering voltage was simulated to 3.6V. And the latch-up characteristics were improved. Finally, we performed the layout high speed I/O interlace circuit with the low triggered ESD protection device in one-chip.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.203.1-203.1
• /
• 2016

Poly etch 설비에서 발생하는 dechuck 불량에 의한 Dynamic Alignment(DA) error는 poly etch 설비에서의 고질 적인 문제이다. 발생 원인은 ElectroStatic Chuck(ESC)의 노후화 혹은process plasma에 의한 attack 등으로 ESC와 wafer간 dechucking이 진행될 때 wafer내의 전하가 완전히 discharge되지 못하여 wafer Sticking에 의한 sliding이 발생되며 심해지면 Dynamic Alignment(DA) Error가 발생한다. DA error 발생 되면 particle down으로 wafer는 scrap 되며 DA error가 지속적으로 발생하는 설비는 ESC 교체를 하고 있다. ESC 교체비용도 매우 크며 교체 전까지 설비가 멈추어있는 시간적인 손실이 발생하게 된다. Dechucking을 진행할 때 Wafer에 잔존하는 전하를 제거 하여 Wafer의 sticking을 줄여 DA error를 근원적으로 방지하기 위해 plasma를 이용하여 wafer와 ESC를 하나의 electric circuit으로 연결시키는 방법으로 wafer에 잔존하는 전하를 제거 시키고자 하였다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.10a
• /
• pp.43-46
• /
• 2003

To develop bevel gear dies that have characteristics of high precision and enough life time, the technology of die manufacturing and design which increase the resistance of wear and fatigue is essentially needed. Here in the study, we have investigated several materials for dies and electrode. And, the most economical and suitable electrode material has been selected through the characteristic analysis of electrode materials such as copper, graphite and chromium copper. With the help of CAD/CAM/CAE, the total manufacturing system of high precision electrode for bevel gear has been established.