• ETRI Journal
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• v.13 no.2
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• pp.21-27
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• 1991

Effects of annealing on the dielectric properties and microstructures of thin tantalum oxide film(25nm) deposited on p-type Si substrate with rf reactive magnetron sputtering were investigated. The leakage current density was remarkably reduced from $10^-8$ to $10^-12$ A/$\mum^2$at the electric field of 2MV/cm after rapid thermal annealing(RTA) in $O_2$at $1000^{\circ}C$, while little leakage reduction was observed after furnace annealing in $O_2$ at $500^{\circ}C$. The structural changes of thin tantalum oxide film after annealing were examined using high resolution electron microscope(HREM). The results of HREM show that substantial reduction in the leakage current density after the RTA in $O_2$ can be attributed to crystallization and reoxidation of the thin amorphous tantalum oxide film.

• Journal of the Korean institute of surface engineering
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• v.35 no.5
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• pp.289-294
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• 2002

ZnTe films have been grown on (100) GaAs substrate with two representative problems. The one is lattice mismatch, the other is thermal expansion coefficients mismatch of ZnTe /GaAs. It claims here, the relationship of film thickness and defects distribution with (100) ZnTe/GaAs using hot wall epitaxy (HWE) growth was investigated by transmission electron microscopy (TEM). It analyzed on the two-sort side using TEM with cross-sectional transmission electron microscopy (XTEM) and high-resolution electron microscopy (HREM). Investigation into the nature and behavior of dislocations with dependence-thickness in (100) ZnTe/ (100) GaAs hetero-structures grown by transmission electron microscopy (TEM). This defects range from interface to 0.7 $\mu\textrm{m}$ was high density, due to the large lattice mismatch and thermal expansion coefficients. The defects of low density was range 0.7$\mu\textrm{m}$~1.8$\mu\textrm{m}$. In the thicker range than 1.8$\mu\textrm{m}$ was measured hardly defects.

• 한국전자현미경학회:학술대회논문집
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• 1999.11a
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• pp.63-65
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• 1999

• Applied Microscopy
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• v.34 no.4
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• pp.255-264
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• 2004

The three-dimensional (3D) structure of an inorganic crystal, $SmZn_{0.67}Sb_2$ (space group P4/nmm, $a=4.26{\AA}\;and\;c=10.37{\AA}$) was solved by electron crystallography. High resolution electron microscopy (HREM) images from 3 different major zone axes and selected-area electron diffraction patterns from 16 different zone axes were combined to obtain a 3D information. A crystallographic image processing (CIP) of HREM images was used for more accurate determination of the crystal structure. As a result of this electron crystallography, average phase errors (${\Phi}_{res}$) of [001], [100] and [110] HREM images are $17.0^{\circ},\;8.3^{\circ}\;and\;21.9^{\circ}$, respectively. Xray crystallography of $SmZn_{0.67}Sb_2$ has attempted to compare accuracy of the structure determination by electron crystallography, which resulted in the cell parameters of $a=4.2976(6){\AA}\;and\;c=10.287(2){\AA}$, and the R-factor ($R_{sym}$) of 4.16%.

• 한국전자현미경학회:학술대회논문집
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• 2005.05a
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• pp.132-137
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• 2005

• Journal of the Korean Ceramic Society
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• v.38 no.3
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• pp.274-279
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• 2001

Pt/Ti/Si 기판 위에 성장시킨 박막 전지용 비정질 산화 바나듐 박막에 고상 전해질 박막 LiPON을 이용하여 전고상형 박막전지를 제작하여 충-방전 시험을 시행하였다. 이렇게 제작된 전고상형 박막전지는 500 사이클 이상까지 평균 15$\mu$Ah의 방전용량을 나타내었으나 초기 사이클 영역부터 방전 용량의 감소가 일어나기 시작했다. 박막 전지의 방전 용량 감소에 따른 비정질 산화 바나듐 박막의 구조적 특성 변화를 관찰하기 위하여 고분해능 현미경 분석을 시행하였다. 충-방전을 하지 않은 초기의 산화 바나듐 박막은 입계를 갖지 않고 다결정 특성을 보이지 않는 완전한 비정질 특성을 보였고 이는 TED 결과와 일치하였다. 그러나 450번의 반복적인 충-방전을 시행한 후의 비정질 산화 바나듐 박막 내에는 microcrystalline 형태의 산화 바나듐의 형성됨을 고분해능 전자 현미경 분석을 통해 발견할 수 있었다. 비정질 산화바나듐 박막의 방전 용량 감소의 원인인 Li의 비가역적 탈-삽입은 비정질 내에 형성된 microcrystalline에 의해 유발된다고 사료된다. 또한 LiPON 전해질 박막과 산화 바나듐 박막사이의 계면에 Li 이온과 산화바나듐과의 반응에 의해 형성된 계면 층에 발견할 수 있었는데 이러한 계면 층 역시 Li 확산과 계면 저항에 영향을 주어 방전 용량 감소에 원인으로 작용한다.

• Korean Journal of Crystallography
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• v.1 no.1
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• pp.1-7
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• 1990

It is shown that the symmetry of the incommensurate phase in Ba2NaNb5O15(BSH) belongs to the four dimensional superspace group C from an analysis of the systematic extinction or the rxtra reflections due to the incommensllrate structure. The resulting superstructure is characterizetl by the space group Ima2(C3l) and the origin of the incommensurability in BSN is briefly discussed. Especially. HREM image have shown the prrscnce of discommensurations. In addition. a group-theoretical consideration of structural phase transitions in BSN is suggested.

• The Korean Journal of Ceramics
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• v.5 no.2
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• pp.142-147
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• 1999

The interaction between commercial $Si_3N_4$ powder and two types of additives (nitrate and oxide additives) during the sintering of $Si_3N_4$ was investigated. The nitrates solution or oxide particles were added as a sintering additives. The surface of mixed powder was observed with FT-IR, TG, and HREM. DTA was used to characterize the reactivity of the powders. The formation of crystalline phases and phase transformation were analyzed by XRD. The adsorption of the additives on the surface of silicon nitride was confirmed in the nitrate salts. It was shown that the adsorption occurred by interaction between the amorphous $SiO_2$ layer on the $Si_3N_4$ surface and metal cations $(Al^{3++\; and \;Y^{3+})$ and anions $(NO_3\;^-\; or\; OH^-)$, resulting in a higher degree of homogeneous distribution of additives.

• Korean Journal of Metals and Materials
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• v.46 no.2
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• pp.105-110
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• 2008

Process of the hydroxyapatite (HA) formation on bioactive titanium metal prepared by NaOH treatment in a modified-simulated body fluid (mSBF) containing bovine serum albumin (BSA) was investigated by high resolution transmission electron microscope attached with energy dispersive X-ray spectrometer (EDX). The amorphous titanate, which was formed on titanium surface by NaOH treatment, combined with the calcium ions in the liquid to form an amorphous calcium titanite. With increasing of soaking time in the liquid, an amorphous calcium titanite combined with the phosphate ions to form an amorphous calcium phosphate with low Ca/P atomic ratio, and it grows as aggregates of plate (or needle)-like substance on titanium surface. The crystalline apatite layers, which are needle-shaped with the c axis parallel to the long axis, are formed in an amorphous calcium phosphate with further increase in soaking time. The formation of needle-shaped apatite layers can be explained by electrostatic effects and difference of concentration between calcium, phosphate, and albumin ions.

• Electronics and Telecommunications Trends
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• v.4 no.4
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• pp.98-107
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• 1989

실제의 결정은 이상적인 결정과는 달리 결함(imperfection or defect)들을 포함하고 있다. 본고에서는 이들 여러가지 결함들 중 격자 결함들에 국한해서, 그 기본적인 특성과 Si 격자에서의 이들 결함들의 구조를 살펴보고, 이것들을 고분해능 전자현미경(High Resolution Transmission Electron Microscopy ; HRTEM or HREM)으로 관찰했을 때, HRTEM의 탈초점 (defocus)에 따른 결함 상(image)의 성질의 변화와 함께 상 특성과 격자구조와의 관계를 살펴보았다.