• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.35D no.12
• /
• pp.59-67
• /
• 1998

In this paper, a rigorous three-dimensional Monte Carlo approach to simulate the sputter yield as a function of the incident ion energy and the incident angle as well as the atomic ejection distribution of the target is presented. The sputter yield of the target atom (Cu, Al) has been calculated for the different species of the incident atoms with the incident energy range of 10 eV ~ 100 KeV, which coincides with the previously reported experimental results. According to the simulation results, the calculated sputter yield tends to increase with the amount of the energy of the incident atoms. Our simulation revealed that the maximum sputter yield can be obtained for the incident atom with 10 KeV for the heavy ion, while the maximum sputter yield for the light ion is for the incident atoms with an energy less than 1 KeV. The sputter yield increases with angle of incidence and seems to have the maximum value at 68$^{\circ}$. For angular distributions of the sputtered particle, the atoms in the direction normal to the surface increase with angle of incidence. Furthermore, we has conducted the parallel computation on CRAY T3E supercomputer and built a GUI(Graphic User Interface) system running the sputter simulator.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.26 no.7
• /
• pp.50-57
• /
• 1989

Tapered etching of polysilicon films has been achieved by implanting phosphorus ions into the polysilicon film and using plasma etch in either $CF_4-O_2\;or\;SF_6$. A two-step plasma etching method is also proposed to control the taper angle of the etched edge without changing the implantion conditions. The taper angle is determined by the ratio of the etch rate of the undamaged region to that of the damaged top region of the polysilicon layer. The ratio is found to be dependent on the implantion dose, the implantion energy and the anisotropy of etching. The minimum angle in our experiments is about $10^{\circ}$. When the two-step etching method is employed, the taper angles can be controlled from the minimum angle up to about $55^{\circ}$.

• Proceedings of the Optical Society of Korea Conference
• /
• 2000.02a
• /
• pp.272-273
• /
• 2000

대용량의 정보처리에 필요한 새로운 광원에 대한 연구가 활발히 진행되고 있는 가운데, 광원과 광변조 능력을 동시에 가지고 있는 VCSEL이 상당한 주목을 받아 왔지만, 이 소자는 발진하는 레이저의 파장이 활성층의 온도 변화에 따라 천이하는 점과, 편광의 변질 등으로 인해 8$\times$8이상의 고집적 어레이 제작이 어려운 단점이 있어 실용화에 어려움을 겪고 있다. 마이크로 디스크의 위스퍼링 갤러리 모드를 응용한 광양자테 (PQR) 레이저가$^{[l,2]}$ 지닌 몇 가지 특성들은 VCSEL이 가진 문제들을 해결할 수 있는 가능성을 제시하고 있다. 수 $\mu$A에서 nA급의 문턱전류로 구동할 수 있어 주입전류에 의한 활성층의 온도변화 통제가 가능하며, VCSEL이 온도가 증가에 따라 출력파장이 선형적으로 증가하는 반면, PQR 레이저의 출력 파장은 (equation omitted)에 비례하여 증가하므로 온도-파장 관계가 포화되는 영역에서는 주입전류나 외기 온도에 의한 영향을 거의 받지 않는 안정성 때문에 고집적 어레이 광원 제작시 유리하다. 또, 레이저 출력면의 각도에 따라 각각 다른 파장의 빛을 방출하므로, 각도에 따른 각 파장별 필터를 이용하면 광센서 등 여러 가지 용도에 응용할 수 있을 것으로 기대된다. (중략)

• Korean Journal of Materials Research
• /
• v.7 no.7
• /
• pp.559-563
• /
• 1997

Ta을 2MeV의 에너지로 가속시켜 1x$10^{17}$atoms/$\textrm{cm}^2$의 농도로 TiC(001)면에 이온 주입시킨 후 비행시간형 직충돌이온산란 분광법(time-of-flight impact-collision ion scattering spectroscopy; TOF-ICISS)을 사용하여 TiC(001)면의 Ta표면 편석을 연구하였다. TOF-ICISS는 표면 수층 깊이까지 원자구조를 측정할 수 있는 수법으로, 이온주입된 시편을 1$600^{\circ}C$에서 300sec동안 진공 가열하여 Ta 원자를 편석시킨 후 스펙트럼의 입사각도 의존성을 구함으로써 Ta원자의 편석 위치 및 농도구배를 조사하였다. [110]및 [100]방위에서 Ta과 Ti의 focusing peak가 서로 같은 입사각도에서 나타나며 편석된 Ta원자는 TiC의 Ti-site에 위치한다. Ta원자는 표면 최외층에만 편석되는 것이 아니라 수층에 걸쳐 Ti-site에 자리하고 있으며, Ta 원자의 농도는 표면 최외층에서 내부 층으로 깊어질수록 작아진다. 이온주입시 생성된 표면층의 탄소 격자 결함은 시편 가열시 벌크에 자리하는 탄소가 확산되어 없어진다.다.

• Journal of IKEEE
• /
• v.24 no.1
• /
• pp.67-71
• /
• 2020

In this study, a simulation model of the harmonic injection sensorless control technique is proposed. This model is suitable for the sensorless technique of low-speed area operation of motors. The motor of this model is permanent magnet motor. For sensorless control, 1kHz square wave is injected. The change in motor constant according to rotor position is realized by having different d-q inductance values. Sensorless techniques is implemented through functions of Simulink and models provided by Simulink libraries. It is shown that the harmonic component contained in the current is extracted using a filter, and the angle of the permanent magnet of the motor is detected using the extracted waveform. The validity of the simulation model is demonstrated through the estimated motor angle waveform and the related waveforms of the motor control applied to the 1kW permanent magnet motor.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.374-374
• /
• 2012

반도체 소자의 크기가 100 nm 이하로 감소되면 통상적인 이온 주입 조건인 이온 에너지, 조사량 및 이온 주입 각도뿐만 아니라 Dose Rate 및 모재 온도가 Dopant Profile을 조절하는 데에 있어서 매우 중요한 인자로 작용한다. 본 연구에서는 Ribbon-beam 및 Spot-beam을 사용하여 활성화 열처리 후 Dopant Profile을 분석하였다. 이온 주입은 모든 시편에서 $BF_2$를 가속 에너지 10 keV 및 조사량 $2{\times}10^{15}/cm^2$로 고정하였다. 이온 주입 후 도펀트 활성화는 100% 질소 분위기 하에서 $850^{\circ}C$-30s 조건으로 RTA 열처리를 수행하였다. Boron 및 Fluorine의 Profile은 SIMS 분석을 통하여 구하였다. Spot-beam은 Ribbon-Beam에 비하여 Dose Rate 및 Cooling Efficiency가 높기 때문에 이온 주입 후 더욱 많은 양의 Primary-defect를 발생시키고 이에 따라 두꺼운 비정질 충을 형성한다. $BF_2$ 이온 주입 된 시편에서 B 및 F의 농도 Peak-height는 a/c 계면에 위치하는 것을 관찰하였다. 또한 B 및 F의 농도 Peak-height는 Silicon 모재의 온도가 증가할수록 증가하는 것을 관찰하였다. Silicon 모재의 온도가 증가함에 따라 Active-area의 면저항이 변화하지 않는 상태에서 Vt (Threshold Voltage)가 급격히 감소함을 관찰 하였다. 비정칠 층의 두께가 증가할수록 a/c 계면 하단에 잔존하는 Residual-defect의 양이 감소하고 이는 측면확산을 감소시키는 역할을 한다는 것이 관찰되었다.

• Transactions of the Korean hydrogen and new energy society
• /
• v.21 no.3
• /
• pp.227-240
• /
• 2010

Coal gasification is heading for a great future as one of the cleanest energy sources, which can produce not only electricity and heat, but also gaseous and liquid fuels from the synthesis. The work focuses on 300MW shell type one-stage entrained flow coal gasifier which is used in the Integrated coal Gasification Combined Cycle(IGCC) plant as a reactor. As constructing an IGCC plant is considerably complicated and expensive compared with a pulverized-coal power plant, it is important to determine optimum design factors and operating conditions using a computational fluid dynamics (CFD) model. In this study, the results of numerical calculations show that $O_2$/Coal ratio, 0.83, Steam/Coal ratio, 0.05, coal particle diameter, $100{\mu}m$, injection angle, $4^{\circ}$ (clockwise) are the most optimum in this research.

• Applied Chemistry for Engineering
• /
• v.19 no.3
• /
• pp.295-298
• /
• 2008

In the reactor for the american standard test method (ASTM) D5757-95 with swirl injection nozzles, the attrition characteristics of sand was investigated. The change of particle size distribution and weight of fine particles were compared to identify the effect of swirl injection nozzle on attrition. The fine particles due to particle attrition increased with increasing gas velocities. The weight of fine particles due to jet attrition was changed with angle of swirl injection nozzle. The fine particles decreased with decreasing the angle of swirl injection nozzle. Also, the change of particle size distribution increased with increasing the number of swirl injection nozzles at the same flow rate.

• Korean Journal of Optics and Photonics
• /
• v.5 no.1
• /
• pp.106-112
• /
• 1994

The injection-locking of the broad-area diode laser was analysed by using the Fabry-Perot model. The far-field pattern of the output beam was able to be treated by superposing the individual beams emitted from the front facet due to the multiple reflections between the front and rear facets. and the exact near and far field patterns were obtained. The angle-steering effect according to change of the incident frequency was changed was calculated and found to be 0.022 degree/GHz with a bandwidth of 120 GHz.20 GHz.

• Korean Journal of Optics and Photonics
• /
• v.5 no.1
• /
• pp.100-105
• /
• 1994

We have reduced the oscillating linewidth of the commercial single mode InGaAsP visible laser diodes which emits in the 657 nm region of the spectrum down to 10 MHz by making a extended cavity employing the Littrow-type grating. The wavelength tuning characteristics of the commercial visible laser diode (CQL820D, Philips Co.) for the grating angle, laser temperature, and injection currents were measured by using the wavemeter. The proportional coefficients of the laser were found to be 1 THzlmrad, 32.4 GHz/K, and 6.14 GHz/mA, respectively.tively.