• 한국전기전자재료학회논문지
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• 제18권4호
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• pp.285-296
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• 2005

Reduced pressure chemical vapor deposition technology has been used to study SiGe heterostructure epitaxy and device issues, including SiGe relaxed buffers, proper control of Ge component and crystalline defects, two dimensional delta doping, and their influence on electrical properties of devices. From experiments, 2D profiles of B and P presented FWHM of 5 nm and 20 nm, respectively, and doses in 5×10/sup 11/ ∼ 3×10/sup 14/ ㎝/sup -2/ range. The results could be employed to fabricate SiGe/Si heterostructure field effect transistors with both Schottky contact and MOS structure for gate electrodes. I-V characteristics of 2D P-doped HFETs revealed normal behavior except the detrimental effect of crystalline defects created at SiGe/Si interfaces due to stress relaxation. On the contrary, sharp B-doping technology resulted in significant improvement in DC performance by 20-30 ％ in transconductance and short channel effect of SiGe HMOS. High peak concentration and mobility in 2D-doped SiGe heterostructures accompanied by remarkable improvements of electrical property illustrate feasible use for nano-sale FETs and integrated circuits for radio frequency wireless communication in particular.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.502-505
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• 2005

Researches about micro technology travel lively in these days. Such many researches are concentrated in the field of materials and a process field. But properties of micro materials should be known to give results of research developed into still more. In these various material properties, mechanical property such as tensile strength, elastic modulus, etc is the basic property. To measure mechanical properties in micro or nano scale, actuating must be very precise. PZT is a famous actuator which becomes a lot of use to measure very precise mechanical properties in micro research field. But PZT has a nonlinearity which is called as hysteresis. Not precision result is caused because of this hysteresis property in PZT actuator. Therefore feedback control method is used in many researches to prevent this hysteresis of PZT actuator. Feedback control method produce a good result in processing view, but cause a loss in a resolution view. In this paper, hysteresis is compensated by open loop control method. Hysteresis property is modeled in Mathematical function and compensated control input is constructed using inverse function of original data. Reliability of this control method can be confirmed by testing nickel thin film that is used in MEMS material broadly.

• 대한화학회지
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• 제54권3호
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• pp.310-316
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• 2010

항균성을 포함한 나노 입자는 높은 활용성으로 인해 다양한 분야에 적용되고 있다. 본 연구는 HEMA (2-hydroxyethylmethacrylate), NVP (N-vinyl pyrrolidone), MMA (methylmethacrylate)에 나노 은 및 백금을 첨가한 후 농도조건을 다양화 하여 $70^{\circ}C$에서 약 40분, $80^{\circ}C$에서 약 40분 마지막으로 $100^{\circ}C$에서 약 40분 동안의 열처리 공정을 거쳐 공중합 하였다. 사용된 나노 은과 백금 입자의 크기는 각각 10 ~ 20 nm를 나타내었다. 중합 후 생성된 고분자를 사용하여 물리적 특성을 측정한 결과, 함수율 34.29 ~ 39.00%, 굴절률 1.422 ~ 1.430을 나타내었으며, 가시광선 투과율 78.8 ~ 92.5% 그리고 인장강도 값은 0.149 ~ 0.179 Kgf을 나타내었다. 나노 은과 백금 입자를 사용한 안 의료용 렌즈 재료는 콘택트렌즈 적용에 요구되는 기본적인 물성을 만족하였다.

• 한국세라믹학회지
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• 제52권6호
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• pp.497-501
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• 2015

Inkjet printing is a widespread technology, offering advantages such as high-quality decoration, a continuous process, and the accurate direct reproduction of patterns or pictures. In inkjet printing technology, the dispersion stability of ceramic ink is one of the most important factors. In this study, the dispersion stability of blue $CoAl_2O_4$ ink for ceramic inkjet printing is systematically investigated. Blue $CoAl_2O_4$ pigment was synthesized by a solid-state reaction and then milled to less than 300nm in size. In order to investigate the influence of the viscosity on the dispersion stability, two types of $CoAl_2O_4$ ceramic inks (termed here Blue L and Blue H) were prepared using different volume ratios of ethylene glycol and ethanol. The Blue L and Blue H ink solutions contained cetyltrimethylammonium bromide(CTAB) as a dispersive agent. The viscosity, surface tension and jetting stability of the $CoAl_2O_4$ ceramic inks were analyzed using a rheometer, a surface tension meter and a dropwatcher. The dispersion stability of the $CoAl_2O_4$ ceramic ink was investigated by a multiple light-scattering method. Blue H, a ceramic ink with higher viscosity, showed much better dispersion stability than the Blue L ceramic ink.

• 한국세라믹학회지
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• 제56권2호
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• pp.197-204
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• 2019

An electrochemical oxygen permeating membrane (OPM) is fabricated using Zr_0.895Sc_0.095Ce_0.005Gd_0.005O_2-δ (ScCeGdZ) as the solid electrolyte and aLa_0.7Sr_0.3MnO₃-bScCeGdZ composite (LZab, electrode) as the electrode. The crystal phase of the electrode and the microstructure of the membrane is investigated with X-ray diffraction and scanning electron microscopy. The electrochemical resistance of the membrane is examined using 2-p ac impedance spectroscopy, and LZ55 shows the lowest electrode resistance among LZ82, LZ55 and LZ37. The oxygen permeation is studied with an oxygen permeation cell with a zirconia oxygen sensor. The oxygen flux of the OPM with LZ55 is nearly consistent with the theoretical value calculated from Faraday's Law below a critical current. However, it becomes saturated above the critical current due to the limit of the oxygen ionic conduction of the OPM. The OPM with LZ55 has a very high oxygen permeation flux of ~ 3.5 × 10^-6 mol/㎠s in I = 1.4 A/㎠.

• Korean Chemical Engineering Research
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• 제55권3호
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• pp.430-435
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• 2017

$Li_4Ti_5O_{12}$ (LTO)는 리튬이차전지용 음극활물질로써 충방전에 따른 체적변화가 매우 적고, 삽입과 탈리 반응에 따른 높은 가역성 때문에 수명 특성이 좋다는 장점을 가지고 있다. 본 연구에서는 LTO의 단점인 낮은 전기전도도를 보완하고자 전도성이 좋은 탄소계열 소재인 그래핀과 CNT를 첨가 하였다. LTO입자가 나노 크기이므로, 그래핀이 LTO표면에 위치하여 전도성 향상을 시키기 어렵다고 생각했다. 따라서 추가로 CNT를 첨가시켜 LTO입자와 그래핀 사이에 전도성 네트워크를 형성하여, 그래핀만 첨가하였을 때 보다 전도성이 향상되었다. 또한 탄소물질의 첨가 시점을 LTO합성 전후로 나누어, 각각의 용량 및 수명특성의 효율을 비교해 보았다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.256-259
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• 2004

[ $V_2O_5$ ] 나노선의 구조 분석을 위해 STM(Scanning Tunneling Microscopy)과 TEM(Transmission Electron Microscopy)을 이용하여 단일 $V_2O_5$ 나노선의 이미지를 얻었다. $V_2O_5$ 나노선은 상온에서 ammonium metavanadate$(NH_4VO_3)$와 양이온 교환수지$(DOWEX50{\times}8-100)$를 2차 증류수에 섞어 합성하였다. STM 시료는 3-APS(3-aminopropyltriethoxysilane)를 전 처리한 실리콘 기판에 $V_2O_5$ 나노선을 올려 만들었고, TEM 시료는 200 mesh/copper 그리드에 침전시켜 준비하였다. STM과 TEM의 결과로부터 $V_2O_5$ 나노선의 기하학적 단면이 $1.5nm{\times}10nm$에 거의 근사하는 것을 확인하였으며 두 이미지의 비교를 통해 $V_2O_5$ 나노선의 표면상태에 대해 논의하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.452-455
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• 2004

In this paper, investigations of the SAMs(self-assembled monolayers) of a thiol-fuctionalized viologen derivatives, $V_8SH$ and $SH_8V_8SH$, where, V is N,N'-dialkylbipyridinium (i.e. a viologen group), have been carried out by elucidate voltammetry date. The redox reactions are highly reversible and can be cycled many times without significant side reaction, which has been known as a nano-gram order mass detector through resonant frequency change self-assembly process of the viologen has been investigated with $QCM({\Delta}F)$. The assembling process of the $V_8SH$ and $SH_8V_8SH$ monolayers can be finished completely in about 1 hour. The measured frequency shift for $V_8SH$ and $SH_8V_8SH$ were about 351 and 172 Hz, respectively. From these values, we calculated that the mass adsorbed $V_8SH$ and $SH_8V_8SH$ were about 375 and 183 ng. We believe that this mass loss is caused by the simultaneous loss of the anions present within the monolayer for charge compensation of the viologen dications and some solvent.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.217-217
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• 2008

$BaTiO_3$는 perovskite 구조를 가지는 대표적인 강유전체 재료로서 MLCC (Multi Layer Ceramic Capacitor), PTC thermistor 등에 널리 사용되어지고 있으며, 그 특성을 향상시키기 위하여 많은 연구가 진행되고 있다. 현제 $BaTiO_3$ 분말 제조의 대표적인 합성법으로는 하소와 분쇄공정이 없는 수열합성법이 대표적이나, 나노 사이즈로 제작시 $BaTiO_3$는 마이크로 크기와 달리 입방정상으로 우세한 상태로 존재한다. 이는 제조과정 중의 hydroxyl defect의 영향과 나노 분말의 표면에너지 증가 때문이라고 보고된다. 따라서 본 연구는 이러한 문제점을 해결하기 위해 일반적인 세라믹 제조 방법인 고상반응법을 이용한 나노 사이즈의 $BaTiO_3$ 제조를 위한 최적의 공정 조건을 확립하기 위하여 본 연구를 진행하였다. 조성은 $BaTiO_3$와 반응온도를 낮추기 위한 anatase의 $TiO_2$를 사용하였고, $BaCO_3/TiO_2$ 의 조성비 (1. 1.01, 1.02, 1.03)를 제어하여 혼합한 후, 24h ball-mill 하여 하소 온도 ($860^{\circ}C{\sim}1000^{\circ}C$) 변화에 따른 입자 사이즈와 입도 분포를 측정하였다. 제조된 $BaTiO_3$분말의 결정 구조 분석을 위하여 XRD (X-ray diffraction) 분석을 수행 하였는데, 분석 결과로부터 제조된 분말들이 정방정 (tetragonal)의 perovskite구조를 갖고 있음을 확인하였다. 또한 분말의 미세구조 확인을 위하여 SEM (scanning electron microscope) 관찰을 수행하였는데, 나노 사이즈의 구형 분말을 얻을 수 있음을 확인할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.157-157
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• 2008

As the minimum feature size of semiconductor devices scales down to nano-scale regime, ultra shallow junction is highly necessary to suppress short channel effect. At the same time, Ni-silicide has attracted a lot of attention because silicide can improve device performance by reducing the parasitic resistance of source/drain region. Recently, further improvement of device performance by reducing silicide to source/drain region or tuning the work function of silicide closer to the band edge has been studied extensively. Rare earth elements, such as Er and Yb, and Pd or Pt elements are interesting for n-type and p-type devices, respectively, because work function of those materials is closer to the conduction and valance band, respectively. In this paper, we increased the work function between Ni-silicide and source/drain by using Pd stacked structure (Pd/Ni/TiN) for high performance PMOSFET. We demonstrated that it is possible to control the barrier height of Ni-silicide by adjusting the thickness of Pd layer. Therefore, the Ni-silicide using the Pd stacked structure could be applied for high performance PMOSFET.