• 한국진공학회지
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• 제20권2호
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• pp.77-85
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• 2011

실리콘(Si)에 비해 상대적으로 밴드 갭이 작고, 열전도도가 낮으며, 기존의 Si 반도체 공정 기술과 호환이 가능한 실리콘-게르마늄(SiGe) 합금은 트랜지스터, 광수신 소자, 태양전지, 열전 소자 등 다양한 전자 소자에서 사용되고 있다. 본 논문에서는 SiGe 합금이 전자소자에 응용되는 원리 및 응용과 관련된 기술적인 논제들을 고찰한다. Si에 비해 밴드 갭이 작은 게르마늄(Ge)이 그 구성 원소인 SiGe 합금의 밴드 갭은 Si과 Ge의 분률과 상관없이 항상 Si의 밴드 갭 보다 작다. 이러한 SiGe의 작은 밴드 갭은 전류 이득의 손실 없이 베이스 두께를 감소시키는 것을 가능하게 하여 바이폴라 트랜지스터의 동작속도를 향상시킨다. 또한, Si이 흡수하지 못하는 장파장 대의 빛을 SiGe이 흡수하여 광전류를 생성하게 함으로써 태양전지의 변환효율을 증가시킨다. 질량이 서로 다른 Si 및 Ge 원소의 불규칙적인 분포에 의해 발생하는 포논 산란 효과 때문에 SiGe 합금은 순수한 Si 및 Ge과 비교할 때 낮은 열전도도를 갖는다. 낮은 열전도도 특성의 SiGe 합금은 전자 소자 구조 내에서의 열 손실을 억제하는데 효과가 있으므로 Si 반도체 공정 기반의 열전 소자의 구성 물질로서 활용이 기대된다.

• 한국식품영양과학회지
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• 제38권11호
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• pp.1535-1542
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• 2009

수삼과 버섯의 새로운 용도를 개발하기 위하여, 수삼추출물이 첨가된 액체배지에서 배양된 노루궁뎅이 균사체 심부발효물의 열수추출물로부터 조다당획분을 조제하였다. 수삼추출물이 액체배지 전체양의 1%, 3%와 5% 첨가된 노루궁뎅이버섯 균사체 심부발효물의 열수추출물로부터 조다당획분(HE-GE-CP-1, 3과 5)이 분획되었을 때, 수율은 각각 5.7, 5.1과 4.8%이었다. 이러한 조다당획분 중 HE-GE- CP-5(saline 대조군의 1.89배)는 HE-GE-CP-1(1.64배)과 HE-GE-CP-3(1.76배)보다 유의적으로 높은 비장세포의 마이토젠 활성을 보여주었다. 또한 HE-GE-CP-5(1.83배)는 소장의 국소 면역조직인 Peyer's patch를 경유한 골수세포 증식활성에서도 HE-CP(1.59배), HE-GE-CP-1(1.44배)과 HE-GE-CP-3(1.69배)보다 높은 활성을 나타내었으며, 항암효과로서의 암전이 억제활성 측정에서는 수삼추출물이 5% 첨가된 조다당획분에서 72.4%의 높은 암전이 억제활성도 보여주었다. 그러나 복강 내 마크로파지의 lysosomal phosphatase의 활성측정에서는 HE-GE-CP-3에서 2.03배의 가장 높은 마크로파지 자극활성을 확인할 수 있었다. 한편, 이러한 면역 및 암전이 억제활성을 갖는 조다당획분인 HE-GE-CP-5는 중성당(63.2%)과 함께 상당량의 산성당(19.3%)을 함유하였으며 단백질은 8.8%가 구성분으로 분석되었다. 이러한 결과로부터 HE-GE-CP-5는 암전이를 억제하기 위한 면역계를 자극할 수 있음이 확인되었으며, 이러한 암전이 억제의 항종양 활성은 마크로파지, 비장세포 및 Peyer's patch cell 등의 활성화 기작과 연계되어 있음을 추정할 수 있었다.

• 한국세라믹학회지
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• 제20권2호
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• pp.99-106
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• 1983

This experiment has been carried out for the purpose of investigating the effect of $Ga_2O_3$ and $GeO_2$ additivies on sintering of magnesium oxide over the temperature range of 130$0^{\circ}C$~150$0^{\circ}C$. The effect of calcining temperature on the bulk densities of fired compacts prepared from this material was observed MgO powder has been obtained by calcining extra reagent grade magnesium carbonate(basic fired) at 90$0^{\circ}C$ for 30 minutes $Ga_2O_3$and GeO2 were added in the ratio of 1, 2, and 3 wt% to MgO and mixed with calcined MgO. The specimens were prepared by compression with pressure of $700kg/cm^2$ than fired at 130$0^{\circ}C$~150$0^{\circ}C$ for 0-5hrs. Sintering behaviour and microstructure of the fired specimens were examined. The optimum calcination temperature of magnesium carbonate was 90$0^{\circ}C$. Densification rates obeyed the equation D=K in t+c. Theoretical density in the case of addition of $Ga_2O_3$ was 23.1 kcal/mole in the case of the additive $GeO_2$ was 14.176kcal/mole. This low value would appear to support a machanism of grain boundatry diffusion The range of average grain size in the case of addition of $Ga_2O_3$ and $GeO_2$ was 21$\mu\textrm{m}$-31$\mu\textrm{m}$.

• 대한전자공학회논문지SD
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• 제42권9호
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• pp.1-8
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• 2005

최근 Mobile용 RF ICs 적용을 위한 RF CMOS 기술과 함께 핵심 기술로 SiGe Heterojunction Bipolar Transistor (HBT) 소자 개발의 중요성이 증대되고 있다. 본 논문은 현재 5GHz 동작 수준의 RF제품에서 주로 사용되는 기술인 $0.35\{mu}m$ 설계 Rule을 적용하여 $f_{max}$ 50GHz에서 동작하는 SiGe BiCMOS 기술 개발에 대한 내용을 논의한다. 본 SiGe HBT에 사용하는 에피막 성장 기술은 Trapezoidal Ge base profile 및 non-selective 방식이고, 에미터 RTA 조건 및 SiGe HBT base에 대한 Vertical Profile 최적화를 수행하였다. hFE 100, $f_{T}\;45GHz,\;NF_{min}\;0.8dB$ 수준으로 우수한 특성 및 기술 경쟁력을 갖는 SiGe BiCMOS 공정 개발 및 양산 기술을 확보하였다. 또한, 기존의 0.35um설계 Rule공정 target떼 부합되는 CMOS소자를 포함시켰으며, RF용 Passive소자로 높은 Q값을 갖는 MIM capacitor(1pF, Q>80), Inductor(2nH $Q\~$l2.5)를 제공하였다

• ALGAE
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• 제27권2호
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• pp.125-134
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• 2012

Germanium dioxide ($GeO_2$) has been used for many years in the cultivation of red and green algae as a means of controlling the growth of diatoms. Brown algae are sensitive to $GeO_2$, however, the basis of this sensitivity has not been characterized. Here we use embryos of $Fucus$ $vesiculosus$ to investigate morphological and physiological impacts of $GeO_2$ toxicity. Morphometric features of embryos were measured microscopically, and physiological features were determined using pulse amplitude modulated (PAM) fluorometry. At 5 mg $L^{-1}$ $GeO_2$, embryos grew slower than controls and developed growth abnormalities. After 24 h, initial zygote divisions were often oblique rather than transverse. Rhizoids had inflated tips in $GeO_2$ and were less branched, and apical hairs were deformed, with irregularly aligned, spheroidal cells. Minimum fluorescence ($F_0$) showed minor differences over the 10 days experiment, and pigment levels (chlorophylls $a$, $c$ and total carotenoids) showed no difference after 10 days. Optimum quantum yield increased from ca. 0.52 at 24 h to 0.67 at 5 days, and $GeO_2$-treated embryos had higher mean values (significant at 3 and 5 days). Optimum quantum yield of photosystem II (${\Phi}_{PSII}$) was stable in control thalli after 5 days, but declined significantly in $GeO_2$. Addition of silica (as $SiO_2$) did not reverse the effects of $GeO_2$. These results suggest that $GeO_2$ toxicity in brown algae is associated with negative impacts at the cytological level rather than metabolic impacts associated with photosynthesis.

• 한국전기전자재료학회논문지
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• 제24권7호
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• pp.584-588
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• 2011

The ZnO thin films doped with Ga and Ge (GZO:Ge) were prepared on glass substrate using RF sputtering system. Structural, morphological and optical properties of the films deposited in different temperatures were studied. Proportion of the element of using target was 97 wt% ZnO, 2.5 wt% Ga and 0.5 wt% Ge with 99.99% highly purity. Structural properties of the samples deposited in different temperatures with 200 w RF power were investigated by field emission scanning electron microscopy, FE-SEM images and x-ray diffraction XRD analysis. Atomic force microscopy, AFM images were able to show the grain scales and surface roughness of each film rather clearly than SEM images. it was showed that increasing temperature have better surface smoothness by FE-SEM and AFM images. Transmittance study using UV-Vis spectrometer showed that all the samples have highly transparent in visible region (300~800 nm). In addition, it can be able to calculate bandgap energy from absorbance data obtained with transmittance. The hall resistivity, mobility, and optical band gap energy are influenced by the temperature.

• 한국전기전자재료학회논문지
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• 제21권8호
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• pp.699-705
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• 2008

Capacitance versus voltage (C-V) characteristics of Ge-nanocrystal (NC)-embedded metal-oxide-semiconductor (MOS) capacitors with $HfO_2$ gate material were investigated in this work. The current versus voltage (I-V) curves obtained from Ge-NC-embedded MOS capacitors fabricated with the $NH_3$ annealed $HfO_2$ gate material reveal the reduction of leakage current, compared with those of MOS capacitors fabricated with the $O_2$ annealed $HfO_2$ gate material. The C-V curves of the Ge-NC-embedded MOS capacitor with $HfO_2$ gate material annealed in $NH_3$ ambient exhibit counterclockwise hysteresis loop of about 3.45 V memory window when bias voltage was varied from -10 to + 10 V. The observed hysteresis loop indicates the presence of charge storages in the Ge NCs caused by the Fowler-Nordheim (F-N) tunneling. In addition, capacitance versus time characteristics of Ge-NC-embedded MOS capacitors with $HfO_2$ gate material were analyzed to investigate their retention property.

• Bulletin of the Korean Chemical Society
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• 제24권3호
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• pp.285-290
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• 2003

An analytical method for the simultaneous determination of trace Ge, As and Se in biological samples by inductively coupled plasma/mass spectrometry has been investigated. The effects of added organic gas into the coolant argon gas on the analyte signal were studied to improve the detection limit, accuracy and precision. The addition of a small amount of methane (10 mL/min.) into the coolant gas channel improved the ionization of Ge, As and Se. The analytical sensitivity of the proposed Ar/CH₄system was superior by at least two-fold to that of the conventional Ar method. In the present method, the detection limits obtained for Ge, As and Se were 0.014, 0.012 and 0.064 ㎍/L, respectively. The analytical reliability of the proposed method was evaluated by analyzing the certified standard reference materials (SRM). Recoveries of 99.9% for Ge, 103% for As, 96.5% for Se were obtained for NIST SRM of freeze dried urine sample. The proposed method was also applied to the biological samples.

• Bulletin of the Korean Chemical Society
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• 제29권2호
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• pp.393-397
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• 2008

Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to determine the presence of germanium and phosphorus in a pure gold bonding wire. The samples were dissolved with hydrobromic acid and nitric acid at room temperature. The quantitation limits were 0.012 mg L-1 at 265.118 nm for Ge and 0.009 mg L-1 at 177.495 nm for P. Using the mixed acid digestion formula of DIW+HBr+HNO3, the recoveries were in the range of 98-100% and the relative standard deviation was within 1.1-2.3%. On the other hand, the amount of Ge decreased by about 16.2% using DIW+HCl+HNO3, due to the formation of a volatile compound. The Ge contents determined using the external method and the standard addition method were 9.45 mg kg-1 and 9.24 mg kg-1, respectively, and the P contents, using the same methods, were 22.49 mg kg-1 and 23.09 mg kg-1, respectively. Both methods were successfully used to determine the trace amounts of P and Ge in the pure gold bonding wire samples.

• 한국광학회지
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• 제18권3호
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• pp.221-225
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• 2007

근적외선에서 발광하는 새로운 증폭 매질인 Bi 첨가 알루미노실리케이트 유리의 용융 온도를 낮추면서도 증폭 특성이 향상될 수 있도록 금속 산화물을 첨가한 샘플을 제작하여 분광학적 특성을 분석하였다. $Li_{2}O$의 조성비가 증가하면 형광스펙트럼의 반폭치는 증가하지만 형광 강도가 저하되고, $GeO_{2}$의 영향으로는 반폭치와 형광 강도가 동시에 증가하였다. $GeO_{2}$를 첨가한 시료에서 광 증폭 특성을 측정한 결과, 이전의 벌크 샘플에서 얻었던 것보다 우수한 증폭 특성을 가지고 있음을 확인하였다.