• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.10a
• /
• pp.154-157
• /
• 2007

The austenite phase observed in low carbon HSLA steels is well known to be decomposed to various bainitic microstructures, such as granular bainite, acicular ferrite and bainitic ferrite during continuous cooling process. These bainitic microstructures have been usually identified by using either scanning electron microscope (SEM) or transmission electron microscope (TEM). However, SEM and TEM images do no exactly coincide, because of the quite different sample preparation method in SEM and TEM observations. These conventional analysis method is, thus, not suitable for characterization of the complex bainitic microstructure. In this study, focused ion beam (FIB) technique was applied to make site-specific TEM specimens and to identify the 3-dimensional grain morphologies of the bainitic microstructure. The morphological feature and grain boundary characteristics of each bainitic microstructure were exactly identified.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.612-612
• /
• 2013

The band-gap opening in graphene is a key factor in developing graphene-based field effect transistors. Although graphene is a gapless semimetal, a band-gap opens when graphene is formed into a graphene nanoribbon (GNR). Moreover, the band-gap energy can be manipulated by the width of the GNR. In this study, we propose a site-specific synthesis of a width-tailored GNR directly onto an insulating substrate. Predeposition of a diamond-like carbon nanotemplate onto a SiO2/Si wafer via focused ion beam-assisted chemical vapor deposition is first utilized for growth of the GNR. These results may present a feasible route for growing a width-tailored GNR onto a specific region of an insulating substrate.

• Korean Journal of Materials Research
• /
• v.3 no.2
• /
• pp.193-196
• /
• 1993

A procedure for preparing cross-sectional specimens for transmission electron microscopy(TEM)by focused ion beam(FIB)milling of specific regions of semiconductor devices is outlined. This technique enables TEM specimens to be pripared at precisely preselected area. In-situ #W thin film deposition on the top surface of desired site is complementally used to secure the TEM specimens to be less wedge shaped, which is main shortcoming of previous FIB-assisted TEM sample preparation technique. This technique is quite useful for the TEM sample priparation for fault finding and the characterization of fabrication process associated with submicron contact technologies.

• International Journal of Korean Welding Society
• /
• v.3 no.2
• /
• pp.29-39
• /
• 2003

The durability and reliability of thermal barrier coatings (TBCs) play an important role in the service reliability, availability and maintainability (RAM) of hot­section components in advanced turbine engines for aero and utility applications. Photostimulated luminescence spectroscopy (PSLS) and electrochemical impedance spectroscopy (EIS) are being concurrently developed as complimentary non­destructive evaluation (NDE) techniques for quality control and life­remain assessment of TBCs. This paper overviews the governing principles and applications of the luminescence and the impedance examined in the light of residual stress, phase constituents and resistance (or capacitance) in TBC constituents including the thermally grown oxide (TGO) scale. Results from NDE by PSLS and EIS are discussed and related to the microstructural development during high temperature thermal cycling, examined by using a variety of microscopic techniques including focused ion beam (FIB) in­situ lift­out (INLO), transmission and scanning transmission electron microscopy (TEM and STEM).

• Applied Microscopy
• /
• v.46 no.1
• /
• pp.14-19
• /
• 2016

Currently, focused ion beams (FIB) are widely used for specimen preparation in atom probe tomography (APT), which is a three-dimensional and atomic-scale compositional analysis tool. Specimen preparation, in which a specific region of interest is identified and a sharp needle shape created, is the first step towards successful APT analysis. The FIB technique is a powerful tool for site-specific specimen preparation because it provides a lift-out technique and a controllable manipulation function. In this paper, we demonstrate a general procedure containing the crucial points of FIB-based specimen preparation. We introduce aluminum holders with moveable pin and an axial rotation manipulator for specimen handling, which are useful for flipping and rotating the specimen to present the backside and the perpendicular direction. We also describe specimen preparation methods for nanowires and nanopowders, using a pick-up method and an embedding method by epoxy resin, respectively.

• Electrical & Electronic Materials
• /
• v.7 no.2
• /
• pp.100-106
• /
• 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.

• Applied Microscopy
• /
• v.41 no.3
• /
• pp.147-154
• /
• 2011

Backscattered electrons (BSE) are generated at the impact of the primary electron beam on the specimen. BSE imaging provides the compositional contrast to resolve chemical features of sectioned block-face. A focused ion beam (FIB) column can be combined with a field emission scanning electron microscope (FESEM) to ensure a dual (or cross)-beam system (FIB-FESEM). Due to the milling of the specimen material by 10 to 100 nm with the gallium ion beam, FIB-FESEM allows the serial block-face (SBF) imaging of plastic-embedded specimens with high z-axis resolution. After contrast inversion, BSE images are similar to transmitted electron images by transmission electron microscopy. As another means of SBF imaging, a specialized ultramirotome has been incorporated into the specimen chamber of FESEM ($3View^{(R)}$). Internal structures of plastic-embedded specimens can be serially revealed and analyzed by $3View^{(R)}$ with a large field of view to facilitate three-dimensional reconstruction. These two SBF approaches by FESEM can be employed to unravel spatial association of (sub)cellular entities for a comprehensive understanding of complex biological systems.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2008.11a
• /
• pp.5.1-5.1
• /
• 2008

• Journal of the KSME
• /
• v.57 no.1
• /
• pp.37-41
• /
• 2017

이 글에서는 대표적인 고에너지 입자빔 기반의 나노가공방법 중에 하나인 집속 이온빔 시스템(focused ion beam system)에 대해 소개하고 이의 응용분야 및 앞으로의 발전 가능성에 대해 논의하고자 한다.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1992.05a
• /
• pp.71-71
• /
• 1992