• Journal of the Semiconductor & Display Technology
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• v.21 no.4
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• pp.53-58
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• 2022

Shape changes of hard mask play a key role in the aspect ratio dependent etch (ARDE). For etch process using high density and energy ions, deformation of hard mask shape becomes more severe, and high aspect ratio (HAR) etch profile is distorted. In this study, polygonal geometric model for shape-deformation of amorphous carbon layered hard mask is suggested to control etch profile during the process. Mask shape is modeled with polygonal geometry consisting of trapezoids and rectangles, and it provides dynamic information about angles of facets and etched width and height of remained mask shape, providing important features for real-time HAR etch profiling.

• Journal of Magnetics
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• v.6 no.3
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• pp.90-93
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• 2001

Co/$Al_O_3$/NiFe and CO/$Al_O_3$/Co tunnel junctions were fabricated by a radio frequency magnetron sputtering at room temperature with hard mask on glass and $4^{\circ}$ tilt cut Si (111) substrates. The barrier layer was formed through two steps. After the Al layer was deposited, it was oxidized in the chamber of a reactive ion etching system (RIE) with $O_2$plasma at various conditions. The dependence of the TMR value and junction resistance on the thickness of Al layer (before oxidation) and oxidation parameters were investigated. Magnetoresistance value of 7% at room temperature was obtained by optimizing the Al layer thickness and oxidation conditions. Circular shape junctions on $4^{\circ}$tilt cut Si (111) substrate showed 4% magnetoresistance. Photovoltaic energy conversion effect was observed with the cross-strip geometry junctions on Si substrate.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.3
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• pp.539-544
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• 1998

Thermoformed appliance, which has been recently introduced for dental usage, is an appliance made of thermoformed sheets and formed with positive or negative pressure under heat. Thermoplastic material is a kind of plastics and can be repeatedly softened by heat. It is classified into hard elastic foil, hard/soft compound foil and soft elastic foil, including BIOPLAST, BIOCRYL, IMPRELON, etc. It has been developed in 1969 and is available in various thickness, shape and color. There are two types of Vacuum former for thermoplastic materials; the pressure type and suction type. The former is much better than the latter for fabrication of various appliances due to its higher pressure. The authors have applied these appliances to some cases - chin cap, active retainer, individual Fluoride tray, mouth protector, bracket transfer mask, bruxism splint(night guard), Essix appliance - by pressure type Vacuum former($Biostar^{(R)}$). The thermoplastic appliances have numerous advantages such as simple procedure, short working time, clean and transparent product, less objectionable taste. But its outstanding advantage would be its excellent biocompatibility bacause it has no monomer and hence no tissue irritation. Although there is some limitations in its usage, it can be used widely for various purposes especaily for pediatric dentistry.