• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.322.2-322.2
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• 2014

Lighting emitting diodes of n-ZnO/MQW/p-GaN structure are fabricated and investigated. To realize this LED structure, n-ZnO/MQW/p-GaN are grown by MOCVD. At several bias voltages, blue-green light is emitted from the ZnO mesa edge. However, the emission is restricted near the mesa edge. It is seen that the hole current does not spread well. It is because conductivity of p-GaN is extremely small. The break down voltage of the device is small compared to conventional InGaN/GaN LEDs. It is seen that ZnO columnar grain boundaries act as leakage current paths and non-radiative recombination center.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.11.1-11.1
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• 2010

As one of the non-vacuum, low temperature fabrication route, electrochemical synthesis has been focused for pursuing the cost-effective pathway to produce high efficiency photovoltaic devices. Especially the availability to form the thin film structure on flexible substrate would be the great advantage of electrochemical process. The successful synthesis of the most favorable absorber materials such as CdTe and CIGS has been reported by many researchers, however, the efficiency of electrochemically synthesized could not exceed that from vacuum process, because of microstructural controllability and compositional variation on devices. In this study, we represent the effect of process parameters on the microstructure and composition of compound semiconductor during the synthesis, and propose the photovoltaic characteristics of electrochemically synthesized solar cells.

• Journal of Korean Vacuum Science & Technology
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• v.3 no.1
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• pp.1-9
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• 1999

This paper presents a newly enhanced damage model in Monte Carlo (MC) simulation for the accurate prediction of 3-Dimensional (3D) as-implanted impurity and point defect profiles induced by ion implantation in (100) crystal silicon. An empirical electronic energy loss model for B, BF2, As, P and Si self implant over the wide energy range has been proposed for the ULSI device technology and development. Our model shows very good agreement with the SIMS data over the wide energy range. In the damage accumulation, we considered the self-annealing effects by introducing our proposed non-linear recomvination probability function of each point defect for the computational efficiency. For the damage profiles, we compared the published RBS/channeling data with our results of phosphorus implants. Our damage model shows very reasonable agreement with the experiments for phosphorus implants.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.129-129
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• 1998

Most of the surface/interface analysis tools have limited depth profiling c capability in terms of the profiling range and the depth resolution. However, M MEIS can profile the surface and subsurface composition and structure q quantitatively and non-destructively with atomic layer depth resolution. I In this presentation, the MEIS system developed at KRISS will be briefly d described with an introduction on the principle of MEIS. Recent MEIS r results on the surface and interface composition and structural change due to i ion bombardment will be presented for preferential sputtering of T:없Os and d damage depth profiles of SHooD, Pt(l11), and Cu(l1D due to Ar+ ion b bombardment. Direct observation of strained Si lattices and its distribution i in the SHool)-SiCh interface and the initial stage of Co growth on Pt(l11) w will be reported. H surfactant effects on epitaxial growth of Ge on Si(ooD w will be discussed with STM results from SND.

• Proceedings of the Korean Vacuum Society Conference
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• 2008.02a
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• pp.314-314
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• 2008

• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.198-205
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• 1992

Abstract-Planarieation technology, which is essential to VLSI, has been developed using non-etch back Spin- On-Glass (SOG). Process factors for 1.5 micron double metal technology are optimized by the statistical design of experiments. Optimum conditions are found to be a process with twice SOG coating, sufficiently long hot plate baking at 300t, and furnace curing for 40 minutes below 400$^{\circ}$C.

• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.134-138
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• 1992

The GaAs/AlAs double barrier structures was grown by MBE(Mo1ecular Beam Epitaxy). Mesa diode was fabricated and I-V characteristics of the diode were measured by semiconductor parameter analyser at room temperature. TEM pictures show the double barrier structure with abrupt interface. PVCR(Peak to Valley Current Ratio) proves to be independent of barrier thickness. These results show that increase in barrier thickness leads to larger valley current by non-resonant tunneling.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.508-508
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• 2012

CST microwave studio is used to simulate the plasma profile of the 450mm CCP source. Standing wave effect becomes important at the high frequency as the electrode radius increases. To solve plasma non-uniformity problem, we designed multi electrode chamber to decreasing standing wave effect. Simulation showed the ratio of input power of each electrode is related with electric field strength. The multi electrode was constructed and measured by 2D probe arrays using floating harmonic method. Uniformity of 450 mm CCP was changed by the ratio of input power of each electrode. We described this dependence with circuit model.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.179-179
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• 2012

Low pressure radio-frequency glow discharges are investigated using theoretical modeling and various experimental diagnostic methods. In the calculations, global models and transformer models are developed to understand the chemical kinetics as well as the electrical properties such as the effective collision frequency, the heating mechanism and the power transferred to the plasma electrons. In addition, Boltzmann equation solver is used to compensate the effect of the electron energy distribution function (EEDF) shape in the global model, and the general expression of energy balance for non-Maxwellian electrons is developed. In the experiments, a number of traditional plasma diagnostic methods are used to compare with calculated results such as Langmuir probe, optical emission spectroscopy (OES), optical absorption spectroscopy (OAS) and two-photon absorption laser-induced fluorescence (TALIF). These theoretical and experimental methods are applied to understand several interesting phenomena in low pressure ICP discharges. The chemical and physical properties of low pressure ICP discharges are described and the applications of these methods are discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.498-498
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• 2012

직류 아크 토치를 이용하여 열플라즈마를 발생시키는 방법은 전극의 구성에 따라 크게 비이송식(non-transferred)과 이송식(transferred)의 2가지 형태로 나눌 수 있다. 1950년대 H. Maecker 등에 의해 이론적 기초가 형성되기 시작한 이송식 아크 플라즈마 발생장치는 처리 대상물질을 전극으로 사용하여 양극에서의 에너지 전달을 직접 이용할 수 있으므로 열효율이 매우 높기 때문에 이를 이용한 고출력 토치에 관한 활발한 연구가 지속되고 있다. 본 연구에서는 대기압 아르곤 자유연소아크 방전에 의해 발생되는 열플라즈마의 열유동 특성을 수치적으로 해석하기 위하여 아크 기둥의 온도, 압력 및 속도 특성을 Navier-Stokes 방정식과 Maxwell 방정식을 연계 계산하였다. 또한 아크-전극 상호작용(arc-electrode interaction) 모델링을 통한 양극(anode)인 처리 대상물질로의 에너지 플럭스 유입을 고려하여 전극 내부의 온도분포를 계산하였다. 해석결과를 검증하기 위하여 음극과 양극 사이 플라즈마 기둥(column)의 중심축 온도는 Haddad & Farmer(1984)의 실험데이터와 비교하였고, 양극으로의 에너지 플럭스 및 온도분포 데이터는 Bini 등(2006)의 실험 및 해석데이터와 비교하여 만족스런 일치를 확인하였다.