• Journal of the Korean Ceramic Society
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• v.37 no.5
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• pp.432-437
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• 2000

Thermoelectric properties of p-type SiGe alloys prepared by a RF inductive furnace were investigated. Non-doped Si80Ge20 alloys were fabricated by control of the quantity of volatile Ge. The carrier of p-type SiGe alloy was controlled by B-doping. B doped p-type SiGe alloys were synthesized by melting the mixture of Ge and Si containing B. The effects of sintering/annealing conditions and compaction pressure on thermoelectric properties (electrical conductivity and Seebeck coefficient) were investigated. For nondoped SiGe alloys, electrical conductivity increased with increasing temperatures and Seebeck coefficient was measured negative showing a typical n-type semiconductivity. On the other hand, B-doped SiGe alloys exhibited positive Seebeck coefficient and their electrical conductivity decreased with increasing temperatures. Thermoelectric properties were more sensitive to compaction pressure than annealing time. The highest power factor obtained in this work was 8.89${\times}$10-6J/cm$.$K2$.$s for 1 at% B-doped SiGe alloy.

• Korean Journal of Medicinal Crop Science
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• v.3 no.3
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• pp.251-258
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• 1995

This study was carried out to find optimum concentration of germanium compounds and pH of medium on the induction and growth of callus from A. keiskei and P. ginseng and to intend to increase Ge. absorption by calli while those calli were subculturing on MS medium. Callus from a. keiskei was rarely induced under light condition. Under dark condition, callus in­duction from A. keiskei was good up to 5ppm, retarded at 50ppm of $GeO_2$, or C. E. Ge. O., and rarely done at 100 ppm of $GeO_2$ but was somewhat well at 100 ppm of C. E. Ge. O. The induction and growth of callus was good in order of pH 5. 7 > pH 5. 4 > pH 6. 0 Under light condition, the growth of callus induced from P. ginseng was poor at $1{\sim}10\;ppm$ of $GeO_2$, or C. E. Ge. O., but shooting from callus occurred frequently. Under dark condtion, the growth of callus from A. keiskei was good up to 5 ppm of $GeO_2$, or C. E. Ge. O. and was rarely done at 50 ppm of $GeO_2$, but was somewhat well even at 100 ppm of C. E. Ge. O. Shooting from callus occurred frequently in a. keiskei, especially at pH 5.7. The growth of callus from P. ginseng was poor at 10 ppm of $GeO_2$, or 50 ppm of C. E. Ge. O. Under dark condition, the amount of Ge absorption by callus induced from A. keiskei was much high­er than that from P. ginseng. The amount of Ge. absorption by callus treated with $GeO_2$, was higher than that treated with C. E. Ge. O.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.95-95
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• 2008

본 연구에서는 SiGe p-MOSFET을 제작하여 I-V 특성과 게이트 길이, $V_D$, $V_G$의 변화에 따른 저주파 노이즈특성을 측정하였다. Si 기판위에 성장한 $Si_{0.88}Ge_{0.12}$으로 제작된 SiGe p-MOSFET의 채널은 게이트 산화막과 20nm 정도의 Si Spacer 층으로 분리되어 있다. 게이트 산화막은 열산화에 의해 70$\AA$으로 성장되었고, 게이트 폭은 $25{\mu}m$, 게이트와 소스/드레인 사이의 거리는 2.5때로 제작되었다. 제작된 SiGe p-MOSFET은 빠른 동작 특성, 선형성, 저주파 노이즈 특성이 우수하였다. 제작된 SiGe p-MOSFET의 ESD 에 대한 소자의 신뢰성과 내성을 연구하기 위하여 SiGe P-MOSFET에 ESD를 lkV에서 8kV까지 lkV 간격으로 가한 후, SiGe P-MOSFET의 I-V 특성과 게이트 길이, $V_D$, $V_G$의 변화에 따른 저주파 노이즈특성 변화를 분석 비교하였다.

• Korean Journal of Exercise Nutrition
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• v.25 no.2
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• pp.15-19
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• 2021

[Purpose] Skeletal muscle glycogen is a determinant of endurance capacity for some athletes. Ginger is well known to possess nutritional effects, such as anti-diabetic effects. We hypothesized that ginger extract (GE) ingestion increases skeletal muscle glycogen by enhancing fat oxidation. Thus, we investigated the effect of GE ingestion on exercise capacity, skeletal muscle glycogen, and certain blood metabolites in exercised rats. [Methods] First, we evaluated the influence of GE ingestion on body weight and elevation of exercise performance in rats fed with different volumes of GE. Next, we measured the skeletal muscle glycogen content and free fatty acid (FFA) levels in GE-fed rats. Finally, we demonstrated that GE ingestion contributes to endurance capacity during intermittent exercise to exhaustion. [Results] We confirmed that GE ingestion increased exercise performance (p<0.05) and elevated the skeletal muscle glycogen content compared to the nonGE-fed (CE, control exercise) group before exercise (Soleus: p<0.01, Plantaris: p<0.01, Gastrocnemius: p<0.05). Blood FFA levels in the GE group were significantly higher than those in the CE group after exercise (p<0.05). Moreover, we demonstrated that exercise capacity was maintained in the CE group during intermittent exercise (p<0.05). [Conclusion] These findings indicate that GE ingestion increases skeletal muscle glycogen content and exercise performance through the upregulation of fat oxidation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.1
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• pp.6-10
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• 2018

Ni germanide (NiGe) is a promising alloy material with small contact resistance at the source/drain (S/D) of Ge MOSFETs. However, it is necessary to reduce the specific contact resistance between NiGe and the doped Ge S/D region in high-performance MOSFETs. In this study, a novel method is proposed to reduce the specific contact resistance between NiGe and p-type Ge (p-Ge) using a Tb interlayer. The specific contact resistance between NiGe and p-Ge was successfully decreased with the introduction of the Tb interlayer. To investigate the mechanism behind the reduction in the specific contact resistance, the elemental distribution and crystalline structure of NiGe were analyzed using secondary ion mass spectroscopy and X-ray diffraction. It is likely that the reduction in specific contact resistance was caused by an increase in the concentration of boron in the space between NiGe and p-Ge due to the influence of the Tb interlayer.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.541-544
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• 1998

A SiGe p-channel MESFET using $\delta-doped$ layers is designed and the considerable enhancement of the current driving capability of the device is observed from the result of simulation. The channel consists of double $\delta-doped$ layers separated by a low-doped spacer which consists of Si and SiGe. A quantum well is formed in the valence band of the Si/SiGe heterojunction and much more holes are accumulated in the SiGe spacer than those in the Si spacer. The saturation current is enhanced by the contribution of the holes inthe spacer. Among the design parameters that affect the performance of the device, the thickness of the SiGe layer and the Ge composition are studied. The thickness of $0~300\AA$ and the Ge composition of 0~30% are investigated, and the saturation current is observed to be increased by 45% compared with a double $\delta-doped$ Si p-channel MESFET.

• Journal of Radiation Protection and Research
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• v.29 no.4
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• pp.237-242
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• 2004

The radioprotective effects of Melatonin and Ge-132 on acute hematopoietic injury was investigated in mice exposed to an acute whole-body radiation dose of 8 Gy. Melatonin was administered intraperitoneally 1 hour before irradiation at a dose of 200 mg/kg, and Ge-132 was administered orally from days 5 to 20 after irradiation at a dose 130 - 150 mg/kg/d. The radioprotective effects were evaluated for spleen using TUNEL assay, and in peripheral blood by counting lymphocyte & WBC. The 4 experimental groups (irradiation-only, melatonin pretreatment, Ge-132 posttreatment, and melatonin pretreatment plus Ge-132 posttreatment) were observed for survival analysis up to 30 days following irradiation. The apoptotic index (47.8% vs 45.9%, p=0.385), and the number of lymphocytes ($97/{\mu}{\ell}\;vs\;101/{\mu}{\ell}$, p=0.898) were not significantly different between the irradiation-only and the melatonin pretreatment group, But the number of WBCs ($147/{\mu}{\ell}\;vs\;306/{\mu}{\ell}$, p=0.010) was higher in the melatonin pretreatment group. The irradiation-only, melatonin, Ge-132, and melatonin plus Ge-132 treatments resulted in survival rate at 30 days of 21.4%, 100%, 35.7%, and 85.7%, respectively. The melatonin pretreatment group in survival analysis between groups was showed significantly higher survival than the irradiation-only(p=0.000), or Ge-132 posttreatment group(p=0.0003). These results indicate that the melatonin may have a potential as an effective radioprotector on acute hematopoietic syndrome following radiation exposure.

• Journal of Ginseng Research
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• v.29 no.3
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• pp.145-151
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• 2005

This study was carried out to determine the optimal submerged culture conditions for production of ginseng root containing germanium using plant tissue culture technology. The ginseng (Panx ginseng C.A. Meyer) .cot induced by plant growth regulators of 0.5 mg/L BAP and 3.0 mg/L NAA was cultured on SH medium and the effects of various $GeO_2$ concentrations, addition time of $GeO_2$ and pH of medium were investigated on fresh weight, saponin production and germanium accumulation in ginseng root. Optimal $GeO_2$ concentrations for fresh weight, saponin and germanium content were 10, 0 and 110ppm, respectively. When $GeO_2$ was added after 2 weeks cultivation of ginseng root, germanium content was higher than that of adding $GeO_2$ at the initial cultivation time, but saponin content and fresh weight were lower. pH 5.5 was found to be the most favorable condition for the growth of ginseng root and germanium accumulation, but saponin production was best at pH 6.0.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.133-133
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• 2010

3-5족 화합물 반도체를 이용한 집광형 삼중 접합 태양전지는 35% 이상의 광변환 효율로 주목을 받고 있다. 일반적으로 삼중 접합 태양전지는 넓은 영역대의 파장을 흡수하기 위해 밴드갭이 다른 InGaP, GaAs, Ge이 사용된다. 그 중 하부셀은 기계적 강도가 높고 장파장을 흡수할 수 있는 Ge이 사용되는데, p-type Ge 기판위에 III-V 결정막 성장 시 5족 원소가 확산되어 pn접합을 형성하게 된다. 이러한 구조를 가진 Ge 하부셀이 효율적으로 홀-전자 쌍을 형성하기 위해서는 두꺼운 베이스와 얇은 에미터 접합이 필요하다. InGaP의 phosphorus는 낮은 확산계수로 인해 GaAs의 arsenic에 비해 얇은 접합이 형성 가능하며, Ge표면 에칭효과가 더 적다는 장점이 있다. 이를 고려해 우리 연구그룹에서는 metalorganic chemical vapor depostion(MOCVD)을 이용하여 Ge기판위에 성장한 InGaP layer의 특성을 관찰해 보았다. <111>로 $6^{\circ}$ 기울어진 p-type Ge(100) 기판위에 MOCVD를 통해 InGaP layer를 형성하였고, 성장된 layer를 atomic force microscope(AFM)와 high-resolution x-ray diffraction(HRXRD)을 이용하여 표면형상, 조성, 응력상태 등을 각각 관찰하였다. 또한 phosphorus 확산에 의해 형성되는 도핑농도는 electrochemical capacitance-voltage(ECV)을 이용하여 관찰하였다. 성장된 Ge기판위의 InGaP layer의 경우 특징적으로 높이 50 nm, 밑변 길이 $1\;{\mu}m$의 경사진 표면을 관찰할 수 있었으며, 이러한 구조는 TMIn과 TMGa의 비율이 증가 할수록 감소하였다. 따라서 이러한 경사진 형태의 구조는 격자 불일치 때문인 것으로 판단된다. 추가적으로 V/III ratio의 최적화를 통해 1.3 nm의 표면 거칠기를 갖는 InGaP layer를 얻을 수 있었다. ECV를 통해 Ge 하부셀의 pn접합 형성을 관찰한 결과 약 160 nm에서 접합이 형성되는 것을 관찰할 수 있었다. 또한, 같은 성장 조건의 샘플을 1000 초 열처리 후에 접합깊이의 변화를 관찰한 결과 180 nm에서 접합이 관찰되었지만, GaAs의 arsenic에 의한 pn접합은 열처리 후에 그 깊이가 170 nm에서 300 nm로 증가 하였다. 따라서 삼중접합 태양전지의 제작 공정을 고려할 경우 phosphorus에 의한 접합 형성이 Ge 하부셀의 동작 특성에 유리할 것으로 판단된다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.385-385
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• 2012

A two terminal N+/P/N+ junction device to replace the conventional selective transistor was studied as a bilateral switching device for spin transfer torque (STT) MRAM based on 3D device simulation. An N+/P/N+ junction structure with $30{\times}30nm$ area requires bi-directional current flow enough to write a data by a drain induced barrier lowering (DIBL) under a reverse bias at N+/P (or P/N+ junction), and high current on/off ratio of 106. The SiGe materials are widely used in hetero-junction bipolar transistors, bipolar compensation metal-oxide semiconductors (BiCMOS) since the band gap of SiGe materials can be controlled by changing the fraction and the strain epilayers, and the drift mobility is increased with the increasing Ge content. In this work, N+/P/N+ SiGe material based junction provides that drive current is increased from 40 to $130{\mu}A$ by increased Ge content from 10~80%. When Ge content is about 20%, the drive current density of SiGe device substantially increased to 2~3 times better than Si-based junction device in case of 28 nm P length, which is sufficient current to operation of STT-MRAM.