• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.202-202
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• 2010

최근 반도체 소자의 미세화에 따라, 단채널 효과에 의한 누설전류 및 소비전력증가 등이 문제가 되고 있다. DRAM의 경우, 캐패시터 영역의 축소문제가 소자집적화를 방해하는 요소로 작용하고 있다. 1T-DRAM은 기존의 DRAM과 달리 캐패시터 영역을 없애고 상부실리콘의 중성영역에 전하를 저장함으로써 소자집적화에 구조적인 이점을 갖는다. 또한 silicon-on-insulator (SOI) 기판을 이용할 경우, 뛰어난 전기적 절연 특성과 기생 정전용량의 감소, 소자의 저전력화를 실현할 수 있다. 본 연구에서는 silicon-germanium-on-insulator (SGOI) 기판을 이용한 1T-DRAM의 열처리온도에 따른 특성 변화를 평가하였다. 기존의 SOI 기판을 이용한 1T-DRAM과 달리, SGOI 기판을 사용할 경우, strained-Si 층과 relaxed-SiGe 층간의 격자상수 차에 의한 캐리어 이동도의 증가효과를 기대할 수 있다. 하지만 열처리 시, SiGe층의 Ge 확산으로 인해 상부실리콘 및 SiGe 층의 두께를 변화시켜, 소자의 특성에 영향을 줄 수 있다. 열처리는 급속 열처리 공정을 통해 $850^{\circ}C$와 $1000^{\circ}C$로 나누어 30초 동안 N2/O2 분위기에서 진행하였다. 그리고 Programming/Erasing (P/E)에 따라 달라지는 전류의 차를 감지하여 제작된 1T-DRAM의 메모리 특성을 평가하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.203-204
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• 2005

PRAM (Phase change Random Access Memory) is one of the most promising candidates for next generation Non-volatile Memories. The Phase change material has been researched in the field of optical data storage media. Among the phase change materials $Ge_2Sb_2Te_5$(GST) is very well known for its high optical contrast in the state of amorphous and crystalline. However, the characteristics required in solid state memory are quite different from optical ones. In this study, the structural properties of GST thin films with composition were investigated for PRAM. The 100-nm thick GeTe and $Sb_2Te_3$ films were deposited on $SiO_2$/Si substrates by RF sputtering system. In order to characterize the crystal structure and morphology of these films, we performed x-ray diffraction (XRD) and atomic force microscopy (AFM).

• Journal of Radiation Industry
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• v.5 no.2
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• pp.101-106
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• 2011

The separation of germanium and gallium ion with metal oxide was introduced into the development of $^{68}Ge/^{68}Ga$ generator. Germanium and gallium within mixed solution were respectively separated by using a liquid-liquid extraction and a column chromatographic method. The separation of Ge within high concentrated hydrochloric and sulfuric acid was conducted by the extraction to $CCl_4$ and the back-extraction to 0.05 M HCl. An optimum condition of the extraction by $CCl_4$ was in 5~7 M HCl and efficiency was around 80%. The gallium was selectively separated by using $Al_2O_3$ among metal oxides as sorbents from the mixed solution in 0.04~0.10 M HCl condition.

• Journal of the Korean Ceramic Society
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• v.43 no.3 s.286
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• pp.177-184
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• 2006

Dy $L_3$-edge XANES and EXAFS spectra of chalcogenide Ge-As-S glass doped with ca. 0.2 wt% dysprosium have been investigated along with some reference Dy-containing crystals. Amplitude of the white-line peak in XANES spectrum of the glass sample turns out to be stronger than that of other reference crystals, i.e., $DY_2S_3,\;Dy_2O_3\;and\;DyBr_3$. It has been verified from the Dy $L_3$-edge EXAFS spectra that a central Dy atom is surrounded by $6.7{\pm}0.5$ sulfur atoms in its first coordination shell in the Ge-As-S glass, which is relatively smaller than 7.5 of the $Dy_2S_3$ crystal. Averaged Dy-S inter-atomic-distance of the glass ($2.78{\pm}0.01{\AA}$) also turns out to be somewhat shorter than that of the $Dy_2S_3$ crystal ($2.82{\pm}0.01{\AA}$). Such nanostructural changes occurring at Dy atoms imply there being stronger covalency of Dy-S chemical bonds in the Ge-As-S glass than in the crystal counterpart. The enhanced covalency in the nanostructural environment of $Dy^{3+}$ ions inside the glass would then be responsible for optical characteristics of the $4f{\leftrightarrow}4f$ transitions of the dopants, i.e., increase of oscillator strengths and spontaneous radiative transition probabilities.

• Korean Journal of Environmental Agriculture
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• v.27 no.3
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• pp.245-252
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• 2008

The growth characteristics and the Germanium (Ge) uptake of rice plant (Hopyungbyeo) in soil with Ge were investigated under different soil textures to obtain the basic information for agricultural utilization of Ge. This study was carried out in the Wagner pot ($15,000^{-1}a$). Ge concentration in soils such as clay loam, silt loam, loam and sandy loam for rice plant cultivation was treated at $8mg\;kg^{-1}$. The growth status of rice plant was almost similar in all soil texture, and rice yield was higher in the order of silt loam > clay loam > loam > sandy loam. In rice bran, the Ge uptakes in silt loam, clay loam, loam and sandy loam were 980, 868, 754 and $803{\mu}g\;pot^{-1}$, respectively. The Ge uptakes of brown rice and polish rice were greater in the order of silt loam > sandy loam > clay loam > loam. In silt loam, the Ge uptake rates in leaf, stem, root, rice bran and brown rice were 19.7, 2.3, 0.03, 3.1 and 0.44%, respectively. Therefore, under the given experimental condition the optimum soil texture for production of functional rice with Ge is a silt loam.

• Applied Biological Chemistry
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• v.48 no.4
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• pp.382-387
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• 2005

The aim of this study was to identify binding properties of germanium (Ge) in Germanium-fortified Yeast using optimum manufacturing process. The ratio of yeast cell and germanium solution was 1 : 0.5 (50%), and pH 6.5, $35^{\circ}C$ and 20 h during fermentation, and Germanium-fortified Yeast produced. In results of the XRD, NMR and FT-IR analysis, it was different adding inorganic Ge $(GeO_2)$ during fermentation process from transformed into germanium in Germanium-fortified Yeast. And germanium concentration was not shown any difference before and after in the dialysis test with SGF (simulated gastric fluids). Therefore, Germanium-fortified Yeast of Geranti made by using biosynthetic technology was considered that transformed into organic properties during fermentation process. And, this result showed that Germanium-fortified Yeast was not dissociated under SGF (simulated gastric fluids) condition because of its structural binding safety. Thus, Germanium-fortified Yeast was transformed into organic germanium during biosynthetic cultivation. It is expected that this Germanium-fortified Yeast can be applied as a new dietary functional materials for cellular immunity, recovery of injured cells and immune system, and possible anticancer activities by activation immune cells like macrophage.

• Journal of Sensor Science and Technology
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• v.7 no.1
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• pp.61-66
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• 1998

High quality c-axis oriented $YBa_{2}Cu_{3}O_{7}$ films were prepared using the pulsed laser deposition on $SrTiO_{3}$(100) substrate. The atomically smooth $SrTiO_{3}$surface with terraces one unit cell in height could be obtained by a high temperature annealing. $YBa_{2}Cu_{3}O_{7}$ thin films deposited on the substrates exhibited layer-by-layer growth with a c-axis unit cell height. $YBa_{2}Cu_{3}O_{7}$ thin films thus prepared showed critical temperature ${\ge}90$ K with transition width ${\le}0.6$ K, room temperature resistivity of ${\sim}300{\mu}{\Omega}cm$, and critical current density ${\sim}4.6{\times}10^{6}A/cm^{2}$ at 77 K.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.43.1-43.1
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• 2007

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06a
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• pp.537-537
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• 1996

• Proceedings of the Korean Vacuum Society Conference
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• 2004.08a
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• pp.258-258
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• 2004