• 한국전기전자재료학회논문지
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• 제35권1호
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• pp.44-49
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• 2022

In this paper, we investigated current (I)- and voltage (V)-sweeping properties in a double-stack structure, Ge₂Sb₂Te₅/Ti/W-doped Ge₈Sb₂Te₁₁, a candidate medium for applications to multilevel phase-change memory. 200-nm-thick and W-doped Ge₂Sb₂Te₅ and W-doped Ge₈Sb₂Te₁₁ films were deposited on p-type Si(100) substrate using magnetron sputtering system, and the sheet resistance was measured using 4 point-probe method. The sheet resistance of amorphous-phase W-doped Ge₈Sb₂Te₁₁ film was about 1 order larger than that of Ge₂Sb₂Te₅ film. The I- and V-sweeping properties were measured using sourcemeter, pulse generator, and digital multimeter. The speed of amorphous-to-multilevel crystallization was evaluated from a graph of resistance vs. pulse duration (t) at a fixed applied voltage (12 V). All the double-stack cells exhibited a two-step phase change process with the multilevel memory states of high-middle-low resistance (HR-MR-LR). In particular, the stable MR state is required to guarantee the reliability of the multilevel phase-change memory. For the Ge₂Sb₂Te₅ (150 nm)/Ti (20 nm)/W-Ge₈Sb₂Te₁₁ (50 nm), the phase transformations of HR→MR and MR→LR were observed at t<30ns and t<65ns, respectively. We believe that a high speed and stable multilevel phase-change memory can be optimized by the double-stack structure of proper Ge-Sb-Te films separated by a barrier metal (Ti).

• IEIE Transactions on Smart Processing and Computing
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• 제3권5호
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• pp.331-337
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• 2014

Ge is becoming an increasingly popular semiconductor material with high Si compatibility for on-chip optical interconnect technology. For a better manifestation of the meritorious material properties of Ge, its surface treatment should be performed satisfactorily before the electronic and photonic components are fabricated. Ex-situ rapid thermal annealing (RTA) processes with different gases were carried out to examine the effects of the annealing gases on the thin-film quality of Ge grown epitaxially on Si substrates. The Ge-on-Si samples were prepared in different structures using the same equipment, reduced-pressure chemical vapor deposition (RPCVD), and the samples annealed in $N_2$, forming gas (FG), and $O_2$ were compared with the unannealed (deposited and only cleaned) samples to confirm the improvements in Ge quality. To evaluate the thin-film quality, room-temperature photoluminescence (PL) measurements were performed. Among the compared samples, the $O_2$-annealed samples showed the strongest PL signals, regardless of the sample structures, which shows that ex-situ RTA in the $O_2$ environment would be an effective technique for the surface treatment of Ge in fabricating Ge devices for optical computing systems.

• 컴퓨터교육학회논문지
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• 제23권4호
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• pp.13-22
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• 2020

본 연구는 일본 교양 정보교육과정 표준을 분석하여, 한국 대학의 교양 정보교육에 대한 시사점을 제공하기 위한 목적이 있다. 목적 달성을 위해 J07-GE, J17-GE와 관련된 다양한 보고서들을 중심으로 두 표준의 변화를 비교하였다. 개정판인 J17-GE가 반영하는 정보학에 대한 지식의 범위와 정도를 살펴보기 위하여 CS에 관한 교육과정 표준들의 관계를 통해 분석하였다. 분석 결과, 컴퓨팅 사고력 관점과 일본 정보학 정의에 기반한 J07-GE, J17-GE를 통해 정보의 원리와 지식은 보편적인 교양으로서 전체 대학생의 역량을 길러줄 수 있음을 확인하였다. 따라서 교육과정을 개발할 때는 지식체계 뿐 아니라 시수, 방법 등에 대한 논의가 함께 고려되어야 할 것이다. 본 연구는 대학 교양 정보교육의 내실화 및 교양 정보교육과정 표준 개발을 위한 방향성을 제시하였다는 점에 의의가 있다.

• 한국임상약학회지
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• 제27권3호
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• pp.150-160
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• 2017

Background: Recently, a fixed combination of grazoprevir and elbasvir (GE) has been introduced to the arsenal of chemotherapeutics to fight against this virus. The study aimed to provide information on the efficacy and safety of GE for the treatment of HCV infection by performing a meta-analysis of literature data. Methods: PubMed and EMBASE database searches were conducted. Among the literature retrieved, pivotal Phase III clinical studies were analyzed. Statistical analysis of the data was performed by RevMan. Results: Four pivotal Phase III clinical studies compared the efficacy and safety of GE. When HCV patients were treated with GE for 12 weeks, the sustained virologic response, defined as the viral RNA level below the lower limit of quantification at 12 weeks after the cessation of therapy (SVR12), was 94.7%. The clinical advantage of GE involves its use by patients with cirrhosis and/or renal failure without dose adjustment. If the genotype (GT) of the causative virus was GT1a with NS5A polymorphism or GT4 with resistance to peginterferon/ribavirin, treatment with GE plus ribavirin for 16 weeks resulted in a better outcome compared to treatment with GE alone for 12 weeks. Adverse events reported during the four clinical studies were 71.09% in the GE arms and it was 76.61% in the non-GE arms, with the most frequent events being mild central nervous system symptoms. Conclusion: GE was generally safe and effective for the treatment of HCV infection. However, since HCV mutates very rapidly and becomes resistant to antiviral agents, long-term monitoring should be mandatory.

• 한국축산식품학회지
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• 제40권3호
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• pp.426-443
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• 2020

In order to investigate the use of oil in water gelled emulsion (GE) prepared with healthier oil combinations as beef fat replacer in the fresh chicken sausage formulations, four batches of fresh sausages were produced. The first batch was control (C) sample formulated with %100 beef fat, other batches were codded as GE50, GE75, and GE100 respective to the percentage of beef fat replaced with GE. The addition of GE to sausage formulation resulted in an increment in moisture and protein contents while a decrement was observed in fat content (p<0.05). pH, cooking yield and water holding capacity values of GE added samples were found lower than C (p<0.05). GE addition caused lower CIE L* values in samples, however, this trend was not observed in CIE a* and CIE b* values. Initially, the lowest peroxide and the highest TBARS values were recorded in GE100 samples on the 0^th d (p<0.05). Peroxide and TBARS values were in the limits. The texture of samples was softened while total saturated fatty acid content reduced up to 52.61% with the incorporation of GE (p<0.05). Taken together, our results showed that GEs can be used as fat replacers in meat product formulations without causing undesirable quality changes.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권6호
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• pp.847-853
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• 2016

Applications of Si have been increasingly exploited and extended to More-Moore, More-than-Moore, and beyond-CMOS approaches. Ge is regarded as one of the supplements for Si owing to its higher carrier mobilities and peculiar band structure, facilitating both advanced and optical applications. As an emerging metal-oxide device, the junctionless field-effect transistor (JLFET) has drawn considerable attention because of its simple process, less performance fluctuation, and stronger immunity against short-channel effects due to the absence of anisotype junctions. In this study, we investigated lateral field scalability, which is equivalent to channel-length scaling, in Si and Ge JLFETs. Through this, we can determine the usability of Si CMOS and hypothesize its replacement by Ge. For simulations with high accuracy, we performed rigorous modeling for ${\mu}_n$ and ${\mu}_p$ of Ge, which has seldom been reported. Although Ge has much higher ${\mu}_n$ and ${\mu}_p$ than Si, its saturation velocity ($v_{sat}$) is a more determining factor for maximum $I_{on}$. Thus, there is still room for pushing More-Moore technology because Si and Ge have a slight difference in $v_{sat}$. We compared both p- and n-type JLFETs in terms of $I_{on}$, $I_{off}$, $I_{on}/I_{off}$, and swing with the same channel doping and channel length/thickness. $I_{on}/I_{off}$ is inherently low for Ge but is invariant with $V_{DS}$. It is estimated that More-Moore approach can be further driven if Si is mounted on a JLFET until Ge has a strong possibility to replace Si for both p- and n-type devices for ultra-low-power applications.

• 한국진공학회지
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• 제19권1호
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• pp.14-21
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• 2010

Ge은 Si에 비하여 높은 이동도를 갖기 때문에 차세대 고속 metal oxide semiconductor field effect transistors (MOSFETs) 소자를 위한 channel 물질로서 각광받고 있다. 그러나 화학적으로 안정한 게이트 산화막의 부재는 MOS 소자에 Ge channel의 사용에 주요한 장애가 되어왔다. 특히, Ge 기판 위에 고품질의 계면 특성을 갖는 게이트 절연막의 제조는 필수 요구사항이다. 본 연구에서, $HfO_xN_y$ 박막은 Ge 기판 위에 플라즈마 원자층 증착법(plasma-enhanced atomic layer deposition, PEALD)을 이용하여 증착되었다. 플라즈마 원자층 증착공정 동안에 질소는 질소, 산소 혼합 플라즈마를 이용한 in situ 질화법에 의하여 첨가되었다. 산소 플라즈마에 대한 질소 플라즈마의 첨가로 성분비를 조절함으로써 전기적 특성과 계면 성질을 향상시키는데 초점을 맞추어서 연구를 진행하였다. 질소 산소의 비가 1：1이었을 때, EOT의 값의 10% 감소를 갖는 고품질의 소자특성을 보여주었다. X-ray photoemission spectroscopy (XPS)와 high resolution transmission electron microscopy (HR-TEM)를 사용하여 박막의 화학적 결합 구조와 미세구조를 분석하였다.

• 대한화학회지
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• 제43권1호
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• pp.36-41
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• 1999

Mercaptoacetic acid를 이용하여 흡착벗김 전압전류법으로 미량의 게르마늄을 정량하는 방법을 연구하였다. 이때 지지전해질은 0.25 M NaCl 용액(pH 6.0)을 사용하였고, mercaptoacetic acid의 농도는 $5.0{\times}10^{-6}M$이 되도록 조절하여 실험하였다. Ge(IV)-Mercaptoacetic acid 착물의 봉우리 전위는 -1.402V vs. Ag/AgCl에서 나타났다. 착물의 봉우리 전위에 미치는 NaCl의 농도, mercaptoacetic acid의 농도, 축적 시간등에 대하여 조사하였다. 또한, Amberlite IRC-718 킬레이트 수지를 다른 이온들로 부터 Ge(IV)을 분리하는데 적용하였다.

• E2M - 전기 전자와 첨단 소재
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• 제7권2호
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• pp.100-106
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• 1994

A bilayer film consisting of a layer of a-Se$_{75}$ Ge$_{25}$ with a surface layer of silver -100[.angs.] thick and a monolayer film of a-Se$_{75}$ Ge$_{25}$ are irradiated with 9[keV] Ga$^{+}$ ion beam. The Ga$^{+}$ ion (10$^{16}$ [ions/cm$^{2}$] exposed a-Se$_{75}$ Ge$_{25}$ and Ag/a-Se$_{75}$ Ge$_{25}$ thin films show an increase in optical absorption, and the absorption edge on irradiation with shifts toward longer wavelength. The shift toward longer wavelength called a "darkening effect" is observed also in film exposure to optical radiation(4.5*10$^{20}$ [photons/cm$^{2}$]). The 0.3[eV] edge shift for ion irradiation films is about twice to that obtained on irradiation with photons. These large changes are primarily due to structural changes, which lead to high etch selectivity and high sensitivity.

• 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.