• JSTS:Journal of Semiconductor Technology and Science
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• 제16권4호
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• pp.470-480
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• 2016

The reversal of a silicon chip to find out its security structure is common and possible at the present time. Thanks to reversing, it is possible to use a probing attack to obtain useful information such as personal information or a cryptographic key. For this reason, security-related blocks such as DES (Data Encryption Standard), AES (Advanced Encryption Standard), and RSA (Rivest Shamir Adleman) engines should be located in the lower layer of the chip to guard against a probing attack; in this regard, the addition of a silicon-surface-protection layer onto the chip surface is a crucial protective measure. But, for manufacturers, the implementation of an additional silicon layer is burdensome, because the addition of just one layer to a chip significantly increases the overall production cost; furthermore, the chip size is increased due to the bulk of the secure logic part and routing area of the silicon protection layer. To resolve this issue, this paper proposes a practical silicon-surface-protection method using a metal layer that increases the security level of the chip while minimizing its size and cost. The proposed method uses a shift register for the alternation and variation of the metal-layer data, and the inter-connection area is removed to minimize the size and cost of the chip in a more extensive manner than related methods.

• 한국표면공학회지
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• 제17권2호
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• pp.29-40
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• 1984

The structure of rapidly solidified Al-Si-based alloys and its relationship to subsequent anodic film growth in near neutral and acid solutions have been investigated. Solidification of the alloys proceeds via pre-dendritic nuclei, associated with rugosity of the casting surface, from which cellular-type growth, comprised of aluminium-rich material surrounded by silicon-containing material, emanates. Observation of ultramicrotomed sections of the alloys and their anodic films reveals the local oxidation of the silicon-rich phase and its incorporation into the anodic alumina film, formed in near neutral solutions. Such incorporation occurs but resultant isolation of the silicon-rich phase is not possible for anodizing in phosphoric acid, and a three-dimensional network of the oxidized silicon-containing phase, with continuing development of porous anodic alumina, is observed.

• Current Photovoltaic Research
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• 제2권3호
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• pp.84-87
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• 2014

Protection of solar cell surface is important to prevent from dust, pollen, sand, etc. Therefore, development of large area antifouling film is urgent for high performance of solar cells. The surface of silica spheres was modified to fabricate large area antifouling film. The surface of monodisperse silica spheres has been modified with 3-(trimethoxysilyl) propylmethacrylate (TMSPM) to fabricate large area photonic crystal. Although the surface modification of silica spheres with TMSPM has been failed for the base catalyst, the second trial using acid catalyst showed the following results. The FTIR absorption peak at $1721cm^{-1}$ representing C=O stretching vibration indicates that the TMSPM was attached on the surface of silica spheres. The methanol solution comprised of the surface modified silica spheres (average diameter of 380 nm) and a photoinitiator was poured in the patterned silicon wafer with the dimension of 10 cm x 10 cm and irradiated UV-light during the self-assembly process. The result showed large area crack and defect free nanostructures.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2014년도 추계학술대회 논문집
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• pp.44-44
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• 2014

Magnesium alloy AZ31 sheet를 자동차용 부품으로 사용하기 위해서는 내식성, 전착도장성등의 신뢰성을 확보해야 한다. 이를 위해서 우리는 Phosphate, manganese, silicon계열의 화성처리제를 이용하여 자동차 부품으로 사용가능한 신뢰성확보를 위해 표면처리 방법에 관한 연구를 진행 하였다.

• 한국전기전자재료학회논문지
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• 제19권9호
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• pp.818-824
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• 2006

The effects of high-temperature process required to fabricate the SiC devices on the surface morphology and the electrical characteristics were investigated for 4H-SiC Schottky diodes. The 4H-SiC diodes without a graphite cap layer as a protection layer showed catastrophic increase in an excess current at a forward bias and a leakage current at a reverse bias after high-temperature annealing process. Moreover it seemed to deviate from the conventional Schottky characteristics and to operate as an ohmic contact at the low bias regime. However, the 4H-SiC diodes with the graphite cap still exhibited their good electrical characteristics in spite of a slight increase in the leakage current. Therefore, we found that the graphite cap layer serves well as the protection layer of silicon carbide surface during high-temperature annealing. Based on a closer analysis on electric characteristics, a conductive surface transfiguration layer was suspected to form on the surface of diodes without the graphite cap layer during high-temperature annealing. After removing the surface transfiguration layer using ICP-RIE, Schottky diode without the graphite cap layer and having poor electrical characteristics showed a dramatic improvement in its characteristics including the ideality factor[${\eta}$] of 1.23, the schottky barrier height[${\Phi}$] of 1.39 eV, and the leakage current of $7.75\{times}10^{-8}\;A/cm^{2}$ at the reverse bias of -10 V.

• ETRI Journal
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• 제24권5호
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• pp.398-400
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• 2002

Using $Cr_2O_3$ thin film, we developed a novel etch-stop technique for the protection of silicon surface morphology during deep ion coupled plasma etching of silica layers. With this technique we were able to etch a silica trench with a depth of over 20 ${\mu}m$ without any damage to the exposed silicon terrace surface. This technique should be well applicable to fabricating silica planar lightwave circuit platforms for opto-electronic hybrid integration.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2003년도 추계학술발표회초록집
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• pp.119-119
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• 2003

Plasma polymerized organic thin films were deposited on Si(100) glass and Copper substrates at 25 ∼ 100 $^{\circ}C$ using cyclohexane and ethylcyclohexane precursors by PECVD method. In order to compare physical and electrochemical properties of the as-grown thin films, the effects of the RF plasma power in the range of 20∼50 W and deposition temperature on both corrosion protection efficiency and physical properties were studied. We found that the corrosion protection efficiency (P$\_$k/), which is one of the important factors for corrosion protection in the interlayer dielectrics of microelectronic devices application, was increased with increasing RF power. The highest P$\_$k/ value of plasma polymerized ethylcyclohexane film (92.1% at 50 W) was higher than that of the plasma polymerized cyclohexane film (85.26% at 50 W), indicating inhibition of oxygen reduction. Impedance analyzer was utilized for the determination of I-V curve for leakage current density and C-V for dielectric constants. To obtain C-V curve, we used a MIM structure of metal(Al)-insulator(plasma polymerized thin film)-metal(Pt) structure. Al as the electrode was evaporated on the ethylcyclohexane films that grew on Pt coated silicon substrates, and the dielectric constants of the as-grown films were then calculated from C-V data measured at 1㎒. From the electrical property measurements such as I-V ana C-V characteristics, the minimum dielectric constant and the best leakage current of ethylcyclohexane thin films were obtained to be about 3.11 and 5 ${\times}$ 10$\^$-12/ A/$\textrm{cm}^2$ and cyclohexane thin films were obtained to be about 2.3 and 8 ${\times}$ 10$\^$-12/ A/$\textrm{cm}^2$.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.2158-2165
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• 2023

Marine radioactivity monitoring is critical for taking immediate action in case of unexpected nuclear accidents at nuclear facilities located near coastal areas. Especially when the level of contamination is not predictable, mobile monitoring systems will be useful for wide-area ocean radiation survey and for determination of the level of radioactivity. Here, we used a silicon photomultiplier and a high-efficiency GAGG crystal to fabricate a compact, battery-powered gamma spectroscopy that can be used in an ocean environment. The developed spectroscopy has compact dimensions of 6.5 × 6.5× 8 cm³ and weighs 560 g. We used LoRa, a low-power wireless protocol for communication. Successful data transmission was achieved within 1.4 m water depth. The developed gamma spectroscopy was able to detect radioactivity from a ¹³⁷Cs point source (3.7 kBq) at a distance of 20 cm in water. Moreover, we demonstrated an unmanned radioactivity monitoring system in a real sea by combining unmanned surface vehicle with the developed gamma spectroscopy. A hidden ¹³⁷Cs source (3.07 MBq) was detected by the unmanned system at a distance of 3 m. After successfully testing the developed mobile spectroscopy in an ocean environment, we believe that our proposed system will be an effective solution for mobile real-time marine radioactivity monitoring.

• 한국건설순환자원학회논문집
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• 제7권4호
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• pp.295-301
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• 2019

현재 국내에서 가장 보편적으로 사용되고 있는 제설제는 염화칼슘이며, 우리나라의 기후 변화에 따라 전국적으로 제설제의 사용량이 증가하고 있는 추세이다. 제설 제빙을 목적으로 하는 제설제는 살포되어 염화물이 용해된 노면수에 의해 동결융해 작용으로 콘크리트에 열화 등의 다양한 피해를 주고 있다. 따라서 본 연구에서는, 콘크리트 표면에 도포하여 외부에서 침투하는 수분을 차단하는 방식인 콘크리트 표면 보호재를 실리콘 기반으로 한 콘크리트 미세기공을 코팅할 수 있도록 반응형 우레탄 폴리머를 제조하여, 분자의 크기 제어와 표면 개질을 통해 혼화제를 선정하여, 콘크리트 적용하였고 침투강화제의 특성 및 도포방법에 따른 콘크리트 기초 물성을 평가하였다.

• 공업화학
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• 제33권3호
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• pp.296-301
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• 2022

UiO-66과 같은 지르코늄 기반 금속유기골격체(Zr-MOFs)는 비표면적이 넓고 선택적 흡착 능력이 뛰어나 전장환경에서 화학작용제 방호 물질로써 주목받고 있다. 하지만 대부분의 금속유기골격체는 약한 금속-유기 리간드 결합과 공극의 존재로 인하여 대기 중에 노출 시 물 분자와의 반응으로 선택적 흡착 성능이 저하되는 문제점이 있다. 이에 본 연구에서는 대표적인 소수성 고분자 물질인 폴리디메틸실록산(PDMS)을 지르코늄 기반 금속유기골격체인 UiO-66 표면에 코팅하였고, 전장환경에서 적용 가능성을 평가하기 위해 고습 환경에서 diisopropyl methylphosphonate (DIMP)와 같은 유사 화학작용제의 흡착 성능 지속성을 코팅 전과 비교하였다. PDMS를 코팅한 UiO-66의 표면 구조와 유기 작용기 분포를 분석한 결과 실리콘이 고르게 도포된 것을 확인하였으며, 접촉각을 측정한 결과 PDMS를 코팅한 UiO-66에서 30° 이상 접촉각이 증가하여 소수성이 증대한 것을 확인하였다. 또한 UiO-66과 PDMS를 코팅한 UiO-66을 흡착제로 사용하여 고습 환경에서 유사 화학작용제인 DIMP의 흡착 성능 지속성을 확인한 결과 PDMS를 코팅한 UiO-66가 기존의 UiO-66에 비하여 높은 DIMP 흡착 성능 지속성을 나타내는 것을 알 수 있었다.