• ETRI Journal
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• 제35권4호
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• pp.638-643
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• 2013

This paper presents a 5-bit digital step attenuator (DSA) using a commercial 0.18-${\mu}m$ silicon-on-insulator (SOI) process for the wideband phased array antenna. Both low insertion loss and low root mean square (RMS) phase error and amplitude error are achieved employing two attenuation topologies of the switched path attenuator and the switched T-type attenuator. The attenuation coverage of 31 dB with a least significant bit of 1 dB is achieved at DC to 20 GHz. The RMS phase error and amplitude error are less than $2.5^{\circ}$ and less than 0.5 dB, respectively. The measured insertion loss of the reference state is less than 5.5 dB at 10 GHz. The input return loss and output return loss are each less than 12 dB at DC to 20 GHz. The current consumption is nearly zero with a voltage supply of 1.8 V. The chip size is $0.93mm{\times}0.68mm$, including pads. To the best of the authors' knowledge, this is the first demonstration of a low phase error DC-to-20-GHz SOI DSA.

• 한국분말재료학회지
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• 제20권1호
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• pp.19-23
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• 2013

Ru films were successfully prepared by plasma-enhanced atomic layer deposition (PEALD) using $Ru(EtCp)_2$ and $NH_3$ plasma. To optimize Ru PEALD process, the effect of growth temperature, $NH_3$ plasma power and $NH_3$ plasma time on the growth rate and preferred orientation of the deposited film was systemically investigated. At a growth temperature of $270^{\circ}C$ and $NH_3$ plasma power of 100W, the saturated growth rate of 0.038 nm/cycle was obtained on the flat $SiO_2$/Si substrate when the $Ru(EtCp)_2$ and $NH_3$ plasma time was 7 and 10 sec, respectively. When the growth temperature was decreased, however, an increased $NH_3$ plasma time was required to obtain a saturated growth rate of 0.038 nm/cycle. Also, $NH_3$ plasma power higher than 40 W was required to obtain a saturated growth rate of 0.038 nm/cycle even at a growth temperature of $270^{\circ}C$. However, (002) preferred orientation of Ru film was only observed at higher plasma power than 100W. Moreover, the saturation condition obtained on the flat $SiO_2$/Si substrate resulted in poor step coverage of Ru on the trench pattern with an aspect ratio of 8:1, and longer $NH_3$ plasma time improved the step coverage.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.215-215
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• 2010

The feasibility of InSbTe (IST) chalcogenide materials prepared by metalorganic chemical vapor deposition (MOCVD) for phase-change memory (PRAM) applications was demonstrated. Films grown below $225^{\circ}C$ exhibited an amorphous structure, and the films grown at $300^{\circ}C$ Cincluded various crystalline phases such as In-Sb-Te, In-Sb, In-Te, and Sb-Te. The composition of the amorphous films grown at $225^{\circ}C$ was dependent on the working pressure. Films grown at $225^{\circ}C$ exhibited a smooth morphology with a root mean square(rms) roughness of less than 1nm, and the step-coverage of the films grown on a trench structure with an aspect ratio of 5:1 was greater than 90%. An increase in deposition time increased the filling rate, while retaining the conformal step-coverage. Films grown at $225^{\circ}C$ for 3h in a working pressure of $13{\times}10^2$ Pa exhibited a reproducible and complete filling in a trench structure.

• 전자공학회논문지A
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• 제30A권1호
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• pp.51-63
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• 1993

기존의 알고리듬들이 완전히 검출하지 못하는 차수 2나 3의 연결된 2-결합고장을 검출하기 위하여 "알고리듬 다"가 제안되었다. 제한된 3-결합고장을 검출하는 "테스트1*", "테스트2*" 및 "알고리듬 라"가 제안되었다. "테스트1*"는 제한된 3-결합고장을 검출하는 측면에서 기존의 알고리듬들보다 시간복잡도가 감소되었다. "테스트2*" 및 "알고리듬 라"는 기존의 알고리듬들과 비교하여 시간복잡도가 감소되었고 개선된 고장 검출능력을 가진다. 그리고 요구하는 고장 검출정도에 따라 "알고리듬 라"를 순차적으로 수행시킬 수 있으며, 메모리를 병렬테스트하는 경우에 "알고리듬 라"를 수행시키면 시간복잡도가 상당히 개선된다. 비선형 번지순서를 발생시키고 두 번지부분으로 분할하여 반도체 RAM의 결합고장을 검출하는 MT(March Test)는 차수 3의 연결된 2-결합고장보다 복잡한 결합고장은 완전히 검출될 수 없다는 것이 입증되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.178-178
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• 2010

With the scaling down of ULSI(Ultra Large Scale Integration) circuit of CMOS(Complementary Metal Oxide Semiconductor)based electronic devices, the electronic devices become more faster and smaller size that are promising field of semiconductor market. However, very narrow line width has some disadvantages. For example, because of narrow line width, deposition of conformal and thin barrier is difficult. Besides, proportion of barrier width is large, thus resistance is high. Conventional PVD(Physical Vapor Deposition) thin films are not able to gain a good quality and conformal layer. Hence, in order to get over these side effects, deposition of thin layer used of ALD(Atomic Layer Deposition) is important factor. Furthermore, it is essential that copper atomic diffusion into dielectric layer such as silicon oxide and hafnium oxide. If copper line is not surrounded by diffusion barrier, it cause the leakage current and devices degradation. There are some possible methods for improving the these secondary effects. In this study, TaNx, is used of Tertiarybutylimido tris (ethylamethlamino) tantalum (TBITEMAT), was deposited on the 24nm sized trench silicon oxide/silicon bi-layer substrate with good step coverage and high quality film using plasma enhanced atomic layer deposition (PEALD). And then copper was deposited on TaNx barrier using same deposition method. The thickness of TaNx was 4~5 nm. TaNx film was deposited the condition of under $300^{\circ}C$ and copper deposition temperature was under $120^{\circ}C$, and feeding time of TaNx and copper were 5 seconds and 5 seconds, relatively. Purge time of TaNx and copper films were 10 seconds and 6 seconds, relatively. XRD, TEM, AFM, I-V measurement(for testing leakage current and stability) were used to analyze this work. With this work, thin barrier layer(4~5nm) with deposited PEALD has good step coverage and good thermal stability. So the barrier properties of PEALD TaNx film are desirable for copper interconnection.

• 한국재료학회지
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• 제17권7호
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• pp.390-395
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• 2007

We systematically investigated the effects of InAs coverage variation, two-step annealing and an asymmetric InGaAs quantum well (QW) on the structural and optical characteristics of InAs quantum dots (QDs) by using atomic force microscopy (AFM), transmission electron microscopy (TEM) and photoluminescence (PL) measurement. The transition of size distribution of InAs QDs from bimodal to multi-modal was noticeably observed with increasing InAs coverage. By means of two-step annealing, it is found that significant narrowing of the luminescence linewidth (from 132 to 31 meV) from the InAs QDs occurs together with about 150 meV blueshift, compared to as-grown InAs QDs. Finally, the InAs QDs emitting at longer wavelength of $1.3\;{\mu}m$ with narrow linewidth were grown by an asymmetric InGaAs QW. The excited-state transition for the InAs QDs with an asymmetric InGaAs QW was not noticeably observed due to the large energy-level spacing between the ground states and the first excited states. The InAs QDs with an asymmetric InGaAs QW will be promising for the device applications such as $1.3\;{\mu}m$ optical-fiber communication.

• 한국재료학회지
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• 제9권8호
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• pp.825-830
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• 1999

FTES/$O_2$-PECVD 방법에 의하여 증착된 SiOF 박막의 특성을 FT-IR, SPS, 그리고 ellipsometry로 분석하였다. 유전상수, breakdown field와 누설전류 밀도는 MIS(Au/SiOF/p-Si) 구조로 형성하여 C-V와 I-V특성곡선으로부터 측정하였다. SiOF박막의 step-coverage는 SEM 단면사진으로 조사하였다. FTES와 $O_2$의 유량을 각각 300sccm으로 반응로에 주입하였을 때 양질의 SiOF 박막이 형성되었다. 형성된 박막의 유전상수는 3.1로서 다른 산화막보다 더 낮은 값으로 나타났다. breakdown field와 누설전류밀도는 약 10MV/cm와 $8{\times}10^{9}A/\textrm{cm}^2$로 측정되었다. $0.3{\mu}{\textrm}{m}$ 금속 패턴에 $2500{\AA}$의 두께로 증착된 SiOF 박막은 전극간에 void가 없이 우수한 덮힘을 보였다.

• 한국기후변화학회지
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• 제7권3호
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• pp.299-314
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• 2016

The aim of this paper is to review integrated assessment studies conducted to address the impacts of climate change sea-level rise on agricultural sector and to derive suggestions for improving the integrated assessment process to assist decision-makers in establishing climate change adaptation policy. We collect integrated assessment studies which are based on the impact-pathway analysis, compare their step-by-step procedures and identify main factors addressed in each step. The assessment process is typically carried out in the sequence of scenario development, determination of assessment scope, physical impact assessment, economic analysis and synthesis of the outcomes from each step. We identify two types of integrated assessment. The first one examines the impacts of changes in temperature and/or precipitation on the crop-cultivation patterns and/or agricultural productivity and resulting economic effects on agricultural sector. The other investigates the impacts of sea-level rise on land use/coverage and resulting economic damages in terms of land-value loss where the effects on agriculture is treated as one sector among others. To enhance integrated assessment, we suggest that 1) scenarios need to incorporate the effects of climate change and sea-level rise simultaneously, 2) scope of the assessment needs to be extended to include ecosystem services as well as crop production, 3) social and cultural aspects need to be considered in addition to economic analysis, and 4) synthesis of the outcomes from each step should be able to combine quantitative as well as qualitative information.

• 한국연초학회지
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• 제26권2호
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• pp.168-178
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• 2004

Uncertainty of final measurement results considering main uncertainty sources being in nicotine of mainstream smoke was estimated. This study was accomplished by using the ISO 'The Guide to the Expression of Uncertainty in Measurement'. Using the two point re-calibration method, uncertainty for nicotine concentration was calculated considering the uncertainty sources of each step. The concentration and uncertainty of nicotine in mainstream smoke was estimated as $153.95{\pm}17.84\;{\mu}g/mL\;(0.77\pm0.089 mg/cig)$. The expanded uncertainty was $17.84 {\mu}g/mL(\pm0.089 mg/cig).$ The reported expanded uncertainty of the measurement is stated as the standard uncertainty of measurement multiplied by a coverage factor of 2, which for a normal distribution corresponds to a coverage probability of approximately $95\%$ The former expression indicates the conversion concentration into the sample.

• 한국의류학회지
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• 제40권5호
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• pp.954-965
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• 2016

This study was designed to help develop an optimized sizing system for the military winter jackets of Korean males. First, we conducted a survey on the supply rate of military winter jackets and the wearing of suitable size jackets in order to identify problems in the current sizing system. We next developed a new sizing system generation method to satisfy the coverage rate and appropriate size number: Hybrid of Grid with Optimization. The findings of this study were: 1. The survey indicated that a 90 (chest girth) size is necessary; in addition, a one-step large size jacket fit well as a right size jacket. 2. We developed three optimized sizing systems for Korean male military winter jackets using the Hybrid of Grid with an optimization method and suggested one of them as a final new sizing system. The new sizing system consisted of two primary dimension: chest girth and stature. It has a 14 size number and its extended coverage rate is larger than the current sizing system and it has a 90 (chest girth) size. It also selected an optimized size for the area of low population density. The new sizing system is therefore considered very effective for Korean male soldiers military winter jackets.