• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.4
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• pp.20-25
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• 2010

An integrated Mach-Zehnder interferometric sensor operating at 632.8 nm was designed and fabricated by the technology of planar rib waveguides. Rib waveguide based on silica system ($SiO_2-SiO_xN_y-SiO_2$) was geometrically designed to have single mode operation and high sensitivity. It was structured by semiconductor fabrication processes such as thin film deposition, photolithography, and RIE (Reactive Ion Etching). With the power observation, propagation loss measurement by cut-back method showed about 4.82 dB/cm for rib waveguides. Additionally the chromium mask process for an etch stop was employed to solve the core damaging problem in patterning the sensing zone on the chip. Refractive index measurement of water/ethanol mixture with this device finally showed a sensitivity of about $\pi$/($4.04{\times}10^{-3}$).

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.28-29
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• 2000

Optical power splitters and/or couplers are important components for optical signal distribution between channels both in wavelength division multiplexing(WDM) systems and photonic integrated circuits(PICs). Since polarization is usually not known after propagation in an optical fiber, passive WDM components have to be polarization insensitivity, Compared to alternatives such as directional couplers or Y-junction splitters, splitters based on multimode interference(MMI) have found a growing interest in recent yens because of their desirable characteristics, such as compact size, low excess loss, wide bandwidth, polarization independence, and relaxed fabrication tolerances$^{(1)}$ . These devices have been fabricated in polymers, silica, or III-V semiconductor materials. A1 $\times$ 4 MMI power splitter on InP materials that were suitable for application in the 1.55-${\mu}{\textrm}{m}$ region$^{(2)}$ . However, the fabrication process of the structure is too complicated and the photolithography tolerance is very tight. Also, a 1 $\times$ 16 InGaAsP/InP MMI power splitter with an excess loss of 2.2dB and a splitting ratio of 1.5dB was demonstrated by using deep etching$^{(3)}$ . The deep etching of the sidewalls through the entire guide layer of the slab waveguide resulted in a number of drawbacks$^{(4)}$ . (omitted)

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.255-255
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• 2010

Recently, nonvolatile memories (NVM) of various types have been researched to improve the electrical performance such as program/erase voltages, speed and retention times. Also, the charge trap memory is a strong candidate to realize the ultra dense 20-nm scale NVM. Furthermore, the high charge efficiency and the thermal stability of SiC nanocrystals NVM with single $SiO_2$ tunnel barrier have been reported. [1-2] In this study, the SiC charge trap NVM was fabricated and electrical properties were characterized. The 100-nm thick Poly-Si layer was deposited to confined source/drain region by using low-pressure chemical vapor deposition (LP-CVD). After etching and lithography process for fabricate the gate region, the $Si_3N_4/SiO_2/Si_3N_4$ (NON) and $SiO_2/Si_3N_4/SiO_2$ (ONO) barrier engineered tunnel layer were deposited by using LP-CVD. The equivalent oxide thickness of NON and ONO tunnel layer are 5.2 nm and 5.6 nm, respectively. By using ultra-high vacuum magnetron sputtering with base pressure 3x10-10 Torr, the 2-nm SiC and 20-nm $SiO_2$ were successively deposited on ONO and NON tunnel layers. Finally, after deposited 200-nm thick Al layer, the source, drain and gate areas were defined by using reactive-ion etching and photolithography. The lengths of squire gate are $2\;{\mu}m$, $5\;{\mu}m$ and $10\;{\mu}m$. The electrical properties of devices were measured by using a HP 4156A precision semiconductor parameter analyzer, E4980A LCR capacitor meter and an Agilent 81104A pulse pattern generator system. The electrical characteristics such as the memory effect, program/erase speeds, operation voltages, and retention time of SiC charge trap memory device with barrier engineered tunnel layer will be discussed.

• Journal of the Korean Society of Industry Convergence
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• v.10 no.4
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• pp.213-219
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• 2007

Glass-to-metal contact should be prevented in the design of any structural glass component. Because glass is extremely brittle and will fracture readily if even a small point load is applied. If the assembly includes a glass component supported by metallic structure, designers should provide a pliable interface of some kind between the two parts. But there happens high demand of glass-to metal contact in semiconductor industries due to adoption of dry cleaning process as one of the good solution to reduce running cost - carry out equipments cleaning with high corrosive and etching gas such as CF4 with keeping process temperature as the same as high service temperature. Therefore the quartz glass have to be received compression by direct contact with metal as the form of weight itself and vacuum pressure and fatigue by vibrations caused by process during the process. In this paper investigation will be carried out on fracture behavior of quartz glass contacted with metal directly under local load and fatigue given by process vibration with apparatus which can give $lox{\backslash}cal$ load and vibration through PZT ceramics to give guideline to prevent unintended fracture of quartz glass.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.4 s.37
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• pp.275-280
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• 2005

We propose a new approach to greatly simplify the fabrication of conventional nanoimprint lithography (NIL) by combined nanoimprint and photolithography (CNP). We introduce a hybrid mask mold (HMM) made from UV transparent material with a UV-blocking Cr metal layer placed on top of the mold protrusions. We used a negative tone photo resist (PR) with higher selectivity to substrate the CNP process instead of the UV curable monomer and thermal plastic polymer that has been commonly used in NIL. Self-assembled monolayer (SAM) on HMM plays a reliable role for pattern transfer when the HMM is separated from the transfer layer. Hydrophilic $SiO_2$ thin film was deposited on all parts of the HMM, which improved the formation of SAM. This $SiO_2$ film made a sub-10nm formation without any pattern damage. In the CNP technique with HMM, the 'residual layer' of the PR was chemically removed by the conventional developing process. Thus, it was possible to simplify the process by eliminating the dry etching process, which was essential in the conventional NIL method.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.16.1-16.1
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• 2011

$TiO_2$ is a promising material for gas sensors. To achieve high sensitivities, the material should exhibit a large surface-to-volume ratio and possess the high accessibility of the gas molecules to the surface. Accordingly, a wide variety of porous $TiO_2$ nanomaterials synthesized by wet-chemical methods have been reported for gas sensor applications. Nonetheless, achieving the large-area uniformity and comparability with well-established semiconductor production processes of the methods is still challenging. An alternative method is soft-templating which utilizes nanostructured inorganic or organic materials as sacrificial templates for the preparation of porous materials. Fabrication of macroporous $TiO_2$ films and hollow $TiO_2$ tubes by soft-templating and their gas sensing applications have been reported recently. In these porous materials composed of assemblies of individual micro/nanostructures, the form of links or necks between individual micro/nanostructures is a critical factor to determine gas sensing properties of the material. However, a systematic study to clarify the role of links between individual micro/nanostructures in gas sensing properties of a porous metal oxide matrix is thoroughly lacking. In this work, we have demonstrated a fabrication method to prepare highly-ordered, embossed $TiO_2$ films composed of anatase $TiO_2$ hollow hemispheres via soft-templating using polystyrene beads. The form of links between hollow hemispheres could be controlled by $O_2$ plasma etching on the bead templates. This approach reveals the strong correlation of gas sensitivity with the form of the links. Our experimental results highlight that not only the surface-to-volume ratio of an ensemble material composed of individual micro/nanostructures but also the links between individual micro/nanostructures play a critical role in evaluating the sensing properties of the material. In addition to this general finding, the facileness, large-scale productivity, and compatability with semiconductor production process of the proposed fabrication method promise applications of the embossed $TiO_2$ films to high-quality sensors.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.6
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• pp.276-281
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• 2021

In order to manufacture a semiconductor circuit, etching, cleaning, and deposition processes are repeated. During these processes, the inside of the processing chamber is exposed to corrosive plasma. Therefore, the coating of the inner wall of the semiconductor equipment with a plasma-resistant material has been attempted to minimize the etching of the coating and particle contaminant generation. In this study, we synthesized yttrium oxyfluoride (YOF) powder by a solid-state reaction using Y₂O₃ and YF₃ as raw materials. Mixing ratio of the Y₂O₃ and YF₃ was varied from 1.0:1.0 to 1.0:1.6. Effects of the mixing ratio on crystal structure and microstructure of the synthesized YOF powder were investigated using XRD and FE-SEM. The synthesized YOF powder was successfully applied to plasma spray coating process on Al substrate.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.260-263
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• 2003

When ICP(Inductive Coupled Plasma type etching and wafer manufacturing is being processed in semiconductor process, a noxious gas in PFC and CFC system is generated. Gas cleaning dry scrubber is to remove this noxious gas. This paper describes a power source device, 2MHz switching frequency class 2kW RF Generator, used as a main power source of the gas cleaning dry scrubber. The power stage of DC/DC converter is consist of full bridge type converter with 100kHz switching frequency Power amplifier is push pull type inverter with 2MHz switching frequency, and transmission line transformer. The adequacy of the circuit type and the reliability of generating plasma in various load conditions are verified through 50$\Omega$ dummy load and chamber experiments result.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.1010-1013
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• 1998

In micromechanical system (MEMS) such as microactuators. thin film has been widely used as structural material. MEMS materials have difference with bulk in terms of mechanical properties. So, we design the advanced test structure for micromechanical properties of MEMS. The designed structure includes the newly developed pre-crack and it is driven by electrostatic force. To measure the fracture toughness, the pre-crack formation in the test structure is developed with conventional etching process. The advanced test structure is fabricated by application of semiconductor technology. After this, we propose analytical methodology to evaluate the fracture toughness and fatigue properties through a prediction of crack behavior from the variations of stiffness and frequency. Additionally, life time of a mirror plane used in DVD(Digital Video Disk) is measured as a function of capacitance and applied voltage under the accelerated conditions. Ultimately, we propose the method to evaluate the micromechanical reliabilities of the MEMS materials using the advanced test structure.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.4
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• pp.14-17
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• 2006

A thin GaN semiconducting film that grows on sapphires due to metalorganic chemical vapor deposition was machined for nanophotonic applications. The thin film had multilayered superlattice structures, including nanoscaled InGaN layers. Eight alternating InGaN/GaN multilayers provided a blue light emission source. Nanoscaled holes, 150 nm in diameter, were patterned on polymethylmethacrylate (PMMA) film using an electron beam lithography system. The PMMA film blocked the etching species. Air holes, 75 nm in diameter, which acted as blue light diffraction sources, were etched on the top GaN layer by an inductively coupled plasma etcher. Hexagonal lattice photonic crystals were fabricated with 230-, 460-, 690-, and 920-nm pitches. The 450-nm wavelength blue light provided the nanodiffraction destructive and constructive interferences phenomena, which were dependent on the pitch of the holes.