• Current Photovoltaic Research
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• v.8 no.1
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• pp.17-26
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• 2020

It is clear that monocrystalline Silicon (Si) ingots are the key raw material for semiconductors devices. In the present industries markets, most of monocrystalline Silicon (Si) ingots are made by Czochralski Process due to their advantages with low production cost and the big crystal diameters in comparison with other manufacturing process such as Float-Zone technique. However, the disadvantage of Czochralski Process is the presence of impurities such as oxygen or carbon from the quartz and graphite crucible which later will resulted in defects and then lowering the efficiency of Si wafer. The heat transfer plays an important role in the formation of Si ingots. However, the heat transfer generates convection in Si molten state which induces the defects in Si crystal. In this study, a crystal growth simulation software was used to optimize the Si crystal growth process. The furnace and system design were modified. The results showed the melt-crystal interface shape can affect the Si crystal growth rate and defect points. In this study, the defect points and desired interface shape were controlled by specific crystal growth rate condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.109-109
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• 2006

Screen printing (SP) metal contact is typically applied to the solar cells for mass production. However, SP metal contact has low aspect ratio, low accuracy, hard control of the substrate penetration and unclean process. On the other hand, photo lithograpy (PL) metal contact can reduce defects by metal contact. In this investigation, PL metal contact was obtained the multi-layer structure of Ti/Pd/Ag by e-beam process. We applied SP metal contact and PL metal contact to single crystalline silicon solar cells, and demonstrated the difference of conversion efficiency. Because PL metal contact silicon solar cell has Jsc (short circuit current density) better than silicon solar cell applied SP metal contact.

• Korean Journal of Crystallography
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• v.14 no.2
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• pp.84-92
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• 2003

The fast pulling is easy to modify the distribution of grown-in defects toward fine size, which can be readily removed by additional treatment. In this experiment, The fast pulled crystals with high pulling late over 1.0 mm/min were grown and their grown-in defect distributions were investigated. In our recent developments in the growth of Cz-Si, it could be found that the cooling rate in a specific temperature range and the uniformity of temperature gradient at solid/liquid interface are more important for the formation of grown-in defect than the pulling rate itself. We analyzed these cooling rates and temperature gradients for the various fast pulled crystals and compared them to the observed formation behavior of the grown-in defects. The effective factor (Ω) for the void defect formation was introduced and it could explain the radial distribution of void defects in the fast-pulled crystals effectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.3
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• pp.210-222
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• 1994

The characteristics of flows, temperatures, and concentrations of oxygen are numerically studies in the Czochralski furnace with a uniform axial magnetic field. Important governing factors to the flow fields include buoyancy, thermocapillarity, centrifugal force, magnetic force, diffusion and segregation coefficients of the oxygen, evaporation coefficient in the form of SiO, and ablation rate of crucible wall. With an assumption that the flow fields have reached the steady state, which means that two velocity components in the meridional plane and circumferential velocity, temperatures, electric current intensity become non-transient, then unsteady concentration field of oxygen has been analyzed with an initially uniform oxygen concentration. Oxygen transports due to convection and diffusion in the Czochralski flow field and oxygen flux through the growing crystal surface has been investigated.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.8
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• pp.94-106
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• 1995

A three-dimensional(3D) Monte Carlo simulator for boron ion implantation into <100>single-crystal silicon considering the mask structure has been developed to predict the mask-dependent impurity doping profiles of the implanted boron at low energies into the reduced area according to the trend of a reduction in the size of semiconductor devices. All relevant important parameters during ion implantation have been taken into account in this simulator. These are incident energy, tilt and rotation of wafer, orientation of silicon wafer, presence of native silicon dioxide layer, dose, wafer temperature, ion beam divergence, masking thickness, and size and structure of open window in the mask. The one-dimensional(1D) results obtained by using the 3D simulator have been compared with the SIMS experiments to demonstrate its capabilities and confirem its reliability, and we obtained relatively accurate 1D doping profiles. Through these 3D simulations considering the hole structure and its size, we found the mask effects during boron ion implantation process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.5
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• pp.410-414
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• 2013

Rapid thermal processing (RTP) abruptly decreases the time required to perform solar cell processes. RTP were used to form emitter of crystalline silicon solar cells. The emitter sheet resistance is studied as a function of time and temperature. The objective of this study is reduction of doping process time with same performance. Emitter difRapid thermal dfusion was carried out by using a spin on doping and a RTP. iffusion was performed in the temperature range of $700{\sim}750^{\circ}C$ for 1m 30s~15 m. Thermal budgets yielded a $50{\Omega}/sq$ emitter using a P509 source. To reduce process time and get high efficiency, rapid thermal diffusion by IR lamp was employed in air atmosphere at $700^{\circ}C$ for 15 m.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.67-70
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• 2006

This paper deals with a single crystalline silicon (SCS) RF MEMS switch for telecommunication system applications. The proposed SCS switch was fabricated using a silicon-on-glass (SiOG) process and its performances in terms of RF responses, switching time, lifetime were characterized. The proposed SCS switch consists of movable plates, mechanical spring structures, which are composed of robust SCS, resulting in mechanically good stability, The measured actuation voltage was 30 V, and with this applied voltage, the insertion loss and isolation characteristics were measured to be 0.05 and 44.6 dB at 2 GHz respectively. The measured switch ON and OFF time were 13 and $9{\mu}s$, respectively. The lifetime of the fabricated switch was tested. Even after over 1 billion cycles repeated ON/OFF actuations, the switch maintained its own characteristics.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.364.1-364.1
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• 2014

고효율 태양전지로 가기 위해서는 태양전지의 후면 패시베이션은 중요한 역할을 한다. 후면 패시베이션 막으로 사용되는 $Al_2O_3$ 막은 $Al_2O_3/Si$ 계면에서 높은 화학적 패시베이션과 Negative Fixed Charge를 가지고 있어 적합한 Barrier막으로 여겨진다. 하지만 이후에 전면 Metal paste의 소성 공정에 의해 $800^{\circ}C$이상 온도를 올려주게 됨에 따라 $Al_2O_3$ 막 내부에 결합되어 있던 수소들이 방출되어 blister가 생성되고 막 질은 떨어지게 된다. 우리는 blister가 생성되는 것을 방지하기 위한 방법으로 PECVD 장비로 SiNx를 증착하는 공정 중에 $N_2O$ 가스를 첨가하여 SiON 막을 증착하였다. SiON막은 $N_2O$가스량을 조절하여 막의 특성을 변화시키고 변화에 따라 소성시 막에 미치는 영향에 대하여 조사하였다. 공정을 위해 $156{\times}156mm2$, $200{\mu}m$, $0.5-3.0{\Omega}{\cdot}cm$ and p-type 단결정 실리콘 웨이퍼를 사용하였고, $Al_2O_3$ 막을 올리기 전에 RCA Cleaning 실행하였다. ALD 장비를 통해 $Al_2O_3$ 막을 10nm 증착하였고 RF-PECVD 장비로 SiNx막과 SiON막을 80nm 증착하였다. 소성로에서 $850^{\circ}C$ ($680^{\circ}C$) 5초동안 소성하고 QSSPC를 통해 유효 반송자 수명을 알아보았다.

• Journal of the Korean Vacuum Society
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• v.4 no.3
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• pp.306-312
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• 1995

본 연구에서는 비정질 실리콘과 CuInSe2와 함께 지상용 태양전지재료로 널리 연구되고 있는 다결정 CdTe 박막의 열처리방법으로서 로열처리와 반도체 공정에서 사용되는 급속열처리 방법을 이용하여 이들 열처리의 효과를 분석함으로써 태양전지용 다결정 CdTeq 박막에 적합한 효율적인 열처리 방법에 대한 연구를 수행하였다. 증착 후 열처리조건에 따른 결정구조, 결정립 크기, 표면과 박막내부의 성분, 밴드갭 에너지값, 그리고 전기비저항 등을 측정하여 태양전지용 CdTe 박막의 물리적.전기적 특성에 미치는 열처리효과를 관찰하였다. 연구결과 30$0^{\circ}C$에서 증착하고 CdCI2 처리 후 $400^{\circ}C$ 30분간 로열처리를 한 경우, 그리고 $200^{\circ}C$에서 증착한 후 $500^{\circ}C$ 부근에서 1분간 급속열처리를 한 경우 다결정 CdTe 박막의 물리적 전기적 특성이 현저히 향상됨을 알 수 있었다. 특히 급속열처리를 한 경우 로열처리에 비해 결정립의 크기는 작으나 전기비저항이 낮고 밴드갭에너지가 단결정에 더욱 접근하며 태양전지용 다결정 CdTe 박막의 열처리 방법으로 적용할 가치가 있는 방법으로 사료된다.

• Journal of the Korean Vacuum Society
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• v.22 no.2
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• pp.105-110
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• 2013

Single crystalline $In_xGa_{1-x}As$ nanowires are grown on Si (111) substrate via Vapor-Liquid-Solid growth mode using metal-organic chemical vapor deposition. The ternary nanowires have been grown with various growth conditions and examined by electron microscopy. The alloy compositions of the nanowires has been investigated using Energy-dispersive X-ray spectroscopy. We have found that the composition gradient of the nanowire becomes larger with growth temperature and V/III ratio.