• Electrical & Electronic Materials
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• v.10 no.7
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• pp.645-650
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• 1997

We manufactured CoNbZr/Cu/CoNbZr multi-layer films by rf magnetron sputtering methods and formed the patterns on the deposited multi-layer films. In this study, we fabricated a new etchant for forming the patterns by the wet etching with etchant and we searched for the best etching conditions and the etchant composition. Cu was etched selectively independent on the concentration of iron chloride solution, but amorphous CoNbZr thin film did not. The etchant was achieved by iron chloride solution(17.5 mol%) mixed with HF (20 mol%) during 150 sec, which etched CoNbZr/Cu/CoNbZr multi-layer films at the same time. Also, the etchant etched CoNbZr/Cu/CoNbZr multi-layer films by the three-step. It was shown that the cross-section had the isotropic structure and excellent etching characteristics with the above etchant.

• Journal of Powder Materials
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• v.28 no.4
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• pp.317-324
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• 2021

High-strength low-alloy (HSLA) steels show excellent toughness when trace amounts of transition elements are added. In steels, prior austenite grain size (PAGS), which is often determined by the number of added elements, is a critical factor in determining the mechanical properties of the material. In this study, we used two etching methods to measure and compare the PAGS of specimens with bainitic HSLA steels having different Nb contents These two methods were nital etching and picric acid etching. Both methods confirmed that the sample with high Nb content exhibited smaller PAGS than its low Nb counterpart because of Nb's ability to hinder austenite recrystallization at high temperatures. Although both etching approaches are beneficial to PAGS estimation, the picric acid etching method has the advantage of enabling observation of the interface containing Nb precipitate. By contrast, the nital etching method has the advantage of a very short etching time (5 s) in determining the PAGS, with the picric acid etching method being considerably longer (5 h).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.8
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• pp.731-735
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• 2003

Ti-indiffused LiNbO$_3$waveguide have been used to various high speed optical device based on electro-optic effect such as modulators, switches, and sensor, etc. In order to high speed modulation of optical modulator have, one of the further devices, needed to increasing of electrode surrounding air by LiNbO$_3$dry etching because of impedance matching for optical and RF phase velocity between waveguide and electrode. We studied property of LiNbO$_3$dry etching after waveguide patterning lot optical modulation by using neutral loop discharge (NLD) plasma.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.133-134
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• 2009

Cold temperature development (CTD) of electron beam (EB) patterned resists and subsequent dry etching were investigated for fabrication of nano-patterned Niobium (Nb). Bulky Nb fims on GaAs substrates were deposited with EB evaporation. Line patterns on Nb cathode were fabricated by EB patterning and reactive ion etching (RIE). Size deviations of nano-sized line patterns from CAD designed patterns are dependent on the EB total exposure, but it can be improved by CTD of EB-exposed resist. Line patterns of 10 to 300 nm widths of EB-exposed resist patterns were drawn under various exposure conditions of $0.2{\mu}s$/dot (total 240,000 dot) with a constant current (50 pA). Compared with room temperature development (RTD), the CTD improves pattern resolution due to the suppression of backscattering effect. RIE with $CF_4$ was performed for formation of several nano-sized line patterns on Nb. Each EB-resist patterned samples with RTDs and CTDs were etched with two different $CF_4$ gas pressures of 5 Pa. Nb etching rate increases while GaAs (or ZEP) etching rate decreases as the chamber pressure increases. This different dependent of the etching rate on the $CF_4$ pressure between Nb and GaAs (or ZEP) has a significant meaning because selective etching of nano-sized Nb line patterns is possible without etching of the underlying active layer.

• Journal of the Korean Ceramic Society
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• v.40 no.9
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• pp.886-890
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• 2003

The etching characteristics of a LiNbO$_3$ single crystal have been investigated using helicon wave plasma source with bias power and the mixture of CF$_4$, HBr, SF$_{6}$ gas parameters. The etching rate of LiNbO$_3$ with etching parameters was evaluated by surface profiler. The etching surface was evaluated by Atomic Force Microscopy (AFM). The surface morphology of the etched LiNbO$_3$ changed with bias power and the mixture of CF$_4$/Ar/Cl$_2$, HBr/Ar/Cl$_2$, and SF$_{6}$/Ar/Cl$_2$ parameters. Optimum etching conditions, considering both the surface flatness and etch rate were determined.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.327-330
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• 2006

We investigated the usefulness of $NbO_{x}$ nanopillars as an etching mask of dry etching for the formation of Si nanodot arrays. The $NbO_{x}$ nanopillar arrays were prepared by the anodic aluminum oxidation process of Al and Nb thin films. The etch rate and etch profile of $NbO_{x}$ nanopillar arrays were examined by varying the experimental conditions such as the concentration of etch gas, coil rf power, and dc bias voltage in the reactive ion etch system using the inductively coupled plasma. As the concentration of $Cl_{2}$ gas increased, the etch rate of $NbO_{x}$nanopillars decreased. With increasing coil rf power and dc bias voltage, the etch rates were found to increase. The etch characteristics and etch mechanism of $NbO_{x}$ nanopillars were investigated by varying the etch time under the selected etch conditions.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.783-786
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• 2003

A simple fabrication method of self-aligned ridge waveguides with dielectric side buffers is demonstrated on +Z- cut LiNbO$_3$. The ridge waveguide is fabricated by a combination of the annealed proton exchange process and the proton-exchanged wet etching technique. The self-aligned process is achieved by wet etching of aluminum.

• Journal of Magnetics
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• v.14 no.2
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• pp.71-74
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• 2009

The magnetic and structural properties of FINEMET (the Hitachi product name of the Fe-Si-B-Nb-Cu alloy) nanopowder with a composition of $Fe_{73.5}Si_{13.5}B_9Nb_3Cu_1$ atomic percent were investigated after annealing, chemical etching, and mechanical milling. The primary and secondary crystallization temperatures were 523 and $550^{\circ}C$, respectively. The grain size of the particles was adjusted by annealing time. Optimally annealed particles exhibited a homogenous microstructure composed of nanometer-sized crystalline grains. The grain boundary of the annealed particles was etched preferentially by chemical etching. Chemically etched particles were broken at the grain boundary by high-energy ball milling. As a result, a nanometer-sized FINEMET powder with a uniform size of crystalline grains was fabricated.

• Applied Chemistry for Engineering
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• v.25 no.1
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• pp.53-57
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• 2014

We describe the preparation of highly-ordered etching pits on the Nb foil through a micromachining. The effects of electrochemical polishing on the formation of uniformly-patterned protective epoxy layer was investigated. Unlike the previous process using $O_2$ plasma, well-ordered etched pits were prepared without any dry processes. As a result, the Nb foil with the well-ordered pits of $10{\mu}m{\times}5{\mu}m$ could be obtained by electrochemical etching in methanolic electrolytes for 10 min.

• Journal of the Korean Ceramic Society
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• v.42 no.4
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• pp.232-236
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• 2005

The etching characteristics of a $LiNbO_{3}$ optical waveguide structure have been investigated using neutral loop discharge plasma with the mixture of $C_{3}F_{8}$ and Ar and the bias power parameters. The etching rate and profile angle of optical waveguide with etching parameters were evaluated by scanning electron microscopy. Also, the etching RMS roughness was evaluated by atomic force microscopy. From the results of optimum etching conditions are the $C_{3}F_{8}$ gas flow ratio of 0.2 and the bias power of 300 W.