• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1194-1197
• /
• 2005

Micro nozzle is employed as a dynamic passive valve in micro fluidic devices. Micro nozzle array is used in micro droplet generation in bio-medical applications and propulsion device for actuating satellite and aerospace ship in vacuum environments. Aperture angle and the channel length of the micro nozzle affect its retification efficiency, and thus it is needed to produce micro nozzle precisely. MEMS process has a limit on making a micro nozzle with high-aspect ratio. Reactive ion etching process can make high-aspect ratio structure, but it is difficult to make the complex shape. Focused ion beam deposition has advantage in machining of three-dimensional complex structures of sub-micron size. Moreover, it is possible to monitor machining process and to correct defected part at simultaneously. In this study, focused ion beam deposition was applied to micro nozzle production.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.24 no.4
• /
• pp.400-406
• /
• 2015

This study researched the structure of the source of an ion milling machine used to fabricate a scanning electron microscope (SEM) sample. An ion source is used to mill out samples of over 1 mm dimension using a broad ion beam to generate plasma between the anode and cathode using a permanent magnet. To mill the sample in the vacuum chamber, the ion source should be greater than 6 kV for a positive ion current over $200{\mu}A$. To discover the optimum operating conditions for the ion miller, the diameter of the extractor, anode shape, and strength of the permanent magnet were varied in the experiments. A silicon wafer was used as the sample. The sputter yield was measured on the milled surface, which was analyzed using the SEM. The wafer was milled by injecting 1 sccm of argon gas into the 0.5 mTorr vacuum chamber.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.50 no.1
• /
• pp.6-10
• /
• 2001

In this study, we investigated the optical properties of sub-wavelength a-Si thin film transmission gratings, especially the polarization effect, the phase difference and the birefringence by using linearly polarized He-Ne laser beam (632.8nm). The a-Si transmission grating of the thickness $of < 0.1 \mum$ with four-type period($\Lambda = 0.4 \mum and 0.6 \mum$ for sub-wavelength and $\Lambda = 1.0 \mum and 1.4 \mum$ for above-wavelength) on quartz substrates have been fabricated using 50 KeV Ga+ Focused-Ion-Beam(FIB) Milling and $CF_4$Reactive-Ion-Etching(RIE) method. Finally, we obtained the trating array of a-Si thin film with a period $0.4 \mum, 0.6 \mum, 1.0 \mum, 1.4 \mum$ which have nearly equal finger spacing and width, sucessfully. Especially, for gratings with $\Lambda = 0.6 \mum(linewidth=0.25 \mum, linespace=0.35\mum), the \etamax at \theta_в=17.0^{\circ}$ is estimated to be 96%. As the results, we believe that the sub-wavelength grating arrayed a-Si thin film has the applicability as the optical device and components.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.175-175
• /
• 1999

Circumventing problems lying in the conventional lithographic techniques, we devised a new method for the fabrication of nanometer scale metal wires inspired by the unique characteristics of carbon nanotubes (CNTs). Since carbon nanotubes could act as masks when CNT-coated thin Au/Ti layer on a SiO2 surface was physically etched by low energy argon ion bombardment 9ion milling), Au/Ti nano-wires were successfully formed just below the CNTs exactly duplicating their lateral shapes. Cross-sectional analysis by transmission electron microscopy revealed that the edge of the metal wire was very sharply developed indicating the great difference in the milling rates between the CNTs and the metal layer as well as the good directionality of the ion milling. We could easily find a few nanometer-wide Au/Ti wires among the wires of various width. After the formation of nano-wires, the CNTs could be pushed away from the metal nano-wire by atomic force microscopy, The lateral force for the removal of the CNTs are dependent upon the width and shape of the wires. Resistance of the metal nano-wires without the CNTs was also measured through the micro-contacts definted by electron beam lithography. since this CNT-based lithographic technique is, in principle, applicable to any kinds of materials, it can be very useful in exploring the fields of nano-science and technology, especially when it is combines with the CNT manipulation techniques.

• 한국초전도학회:학술대회논문집
• /
• v.10
• /
• pp.165-168
• /
• 2000

We fabricated ramp-edge Josephson junctions with barriers formed by interface treatments instead of epitaxially grown barrier layers. A low-dielectric Sr$_2$AlTaO$_6$(SAT) layer was used as an ion-milling mask as well as an insulating layer for the ramp-edge junctions. An ion-milled YBa$_2$Cu$_3$O$_{7-x}$ (YBCO)-edge surface was not exposed to solvent through all fabrication procedures. The barriers were produced by structural modification at the edge of the YBCO base electrode using high energy ion-beam treatment prior to deposition of the YBCO counter electrode. We investigated the effects of high energy ion-beam treatment, annealing, and counter electrode deposition temperature on the characteristics of the interface-controlled Josephson junctions. The junction parameters such as T$_c$, I$_c$c, R$_n$ were measured and discussed in relation to the barrier layer depending on the process parameters.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.06a
• /
• pp.111-112
• /
• 2008

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.3 s.246
• /
• pp.328-333
• /
• 2006

Movable nanometer-scale structures are fabricated by selective etching of single crystalline Au nanoplates. The nanostructures have arbitrary shapes like gear and alphabet 'A' with in-plane size less than 500 m and thickness of $25\sim60nm$. They could be moved successfully on the substrate using a nanornanipulator installed in a focused ion beam system. Our approach is expected to be useful in fabricating various kinds of nanocomponents which can play a role as building blocks for the sophisticated nanodevices or micromachines.

• Applied Microscopy
• /
• v.45 no.4
• /
• pp.218-224
• /
• 2015

A technical overview on the various sample preparation methods for electron backscattered diffraction (EBSD) analysis is carried out. The mechanical polishing with colloidal silica finish, electro-chemical polishing, dual layer coating and ion beam milling are introduced for the common sample preparation methods for EBSD observation and some issues that are frequently neglected by the common EBSD users but should be considered to get a reliable EBSD data are discussed. This overview would be especially helpful to the people who know what EBSD technique is but do not get a reliable EBSD data because of difficulties in sample preparation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.27 no.11
• /
• pp.679-685
• /
• 2014

For the measurements of surface shape milled using FIB (focused ion beam), the silicon bulk, $Si_3N_4/Si$, and Al/Si samples are used and observed the shapes milled from different sputtering rates, incident angles of $Ga^+$ ions bombardment, beam current, and target material. These conditions also can be influenced the sputtering rate, raster image, and milled shape. The fundamental ion-solid interactions of FIB milling are discussed and explained using TRIM programs (SRIM, TC, and T-dyn). The damaged layers caused by bombarding of $Ga^+$ ions were observed on the surface of target materials. The simulated results were shown a little bit deviation with the experimental data due to relatively small sputtering rate on the sample surface. The simulation results showed about 10.6% tolerance from the measured data at 200 pA. On the other hand, the improved analytical model of damaged layer was matched well with experimental XTEM (cross-sectional transmission electron microscopy) data.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.318-321
• /
• 2005

FIB (Focused ion Beam) milling on a 500-nm-thick silicon nitride membrane was studied in order to fabricate a high-resolution shadow mask, or called a nanostencil. The silicon nitride membrane was fabricated by MEMS processes of LPCVD, photolithography, ICP etching and bulk silicon etching. The apertures made by FIB milling and normal photolithography were compared. The square metal pattern deposited through FIB milled shadow mask showed 6 times smaller comer radius than the case of photolithography. The results show high resolution patterning could be achieved by local deposition through FIB milled shadow-mask.