• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2017년도 춘계학술대회 논문집
• /
• pp.96.2-96.2
• /
• 2017

This research was conducted to investigate the electrochemical properties of the thin air-formed oxide film-covered AZ31 Mg alloy. In this work, native air-formed oxide films on AZ31 Mg alloy samples were prepared by knife-abrading method and the changes in the electrochemical properties of the air-formed oxide film were investigated in seven different electrolytes containing the following anions $Cl^-$, $F^-$, $SO{_4}^{2-}$, $NO_3{^-}$, $CH_3COO^-$, $CO{_3}^{2-}$ and $PO{_4}^{3-}$. It was observed from open circuit potential (OCP) transients that the potential initially decreased before gradually increasing again in the solutions containing only $CO{_3}^{2-}$ or $PO{_4}^{3-}$ ions, indicating the dissolution or transformation of the native air-formed oxide film into new more protective surface films. The Nyquist plots obtained from electrochemical impedance spectroscopy (EIS) showed that there was growth of new surface films with immersion time on the air-formed oxide film-covered specimens in all the electrolytes; the least resistive surface films were formed in fluoride and sulphate baths whereas the most protective film was formed in phosphate bath. The potentiodynamic polarization curves illustrated that passive behaviour of AZ31 Mg alloy under anodic polarization appears only in $CO{_3}^{2-}$ or $PO{_4}^{3-}$ ions containing solutions and at more than $-0.4V_{Ag/AgCl}$ in $F^-$ ion containing solution.

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 1996년도 재료학회 추계학술발표회
• /
• pp.152-153
• /
• 1996

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2010년도 춘계학술대회 논문집
• /
• pp.537-538
• /
• 2010

• 한국재료학회지
• /
• 제14권6호
• /
• pp.402-406
• /
• 2004

$WSi_2$, $TiSi_2$, $CoSi_2$, and $TaSi_2$ are general silicides used today in semiconductor devices. $WSi_2$ thin films have been proposed, studied and used recently in CMOS technology extensively to reduce sheet resistance of polysilicon and $n^{+}$ region. However, there are several serious problems encountered because $WSi_2$ is oxidized and forms a native oxide layer at the interface between $WSi_2$ and $Si_3$$N_4$. In this study, we have introduced 20 $slm-N_2$ gas from top to bottom of the furnace in order to control native oxide films between $WSi_2$ and $Si_3$$N_4$ film. In resulting SEM photographs, we have observed that the native oxide films at the surface of $WSi_2$ film are removed using the long injector system.

• 한국전기전자재료학회논문지
• /
• 제33권3호
• /
• pp.245-248
• /
• 2020

The wettability of silicon carbide (SiC) crystal, which has 6H-SiC and 4H-SiC regions prepared using the physical vapor transport (PVT) method, is quantitatively analyzed using dispensed deionized (DI) water droplets. Regardless of the polytypes in SiC, the average of five contact angle measurements showed a difference of about 6° between the Si-face and C-face. The contact angle on the Si-face (C-face) is measured after the removal of the native oxide using BOE (6:1), and revealed a significant decrease of the contact angle from 74.9° (68.4°) to 47.7° (49.3°) and from 75.8° (70.2°) to 51.6° (49.5°) for the 4H-SiC and 6H-SiC regions, respectively. The contact angle of the Si-face recovered over time during room temperature oxidation in air; in contrast, that of the C-face did not recover to the initial value. This study shows that the contact angle is very sensitive to SiC surface polarity, specific surface conditions, and process time. Contact angle measurements are expected to be a rapid way of determining the surface polarity and wettability of SiC crystals.

• 대한전자공학회논문지SD
• /
• 제41권8호
• /
• pp.31-36
• /
• 2004

본 논문에서는 UV 처리와 BOE 세정을 이용하여 레이저 어닐링 전의 실리콘 표면에 자연 산화막을 제거하여 다결정 실리콘 TFT의 신뢰성을 향상시키는 방법을 제안하였다. 전처리 공정이 다결정 실리콘의 표면 거칠기에 미치는 영향을 AFM으로 측정하였으며, 다결정 실리콘 TFT의 전기적 특성인 스위칭 특성과 항복특성을 대형 유리기판의 위치와 전처리의 유무에 대해서 조사하였다.

• 한국식품과학회지
• /
• 제37권1호
• /
• pp.44-49
• /
• 2005

쌀 전분에 propylene oxide(PO)를 단계별(전분 공형분 대비 2-12%)로 20시간과 24시간 반응시켜 하이드록시프로필화 쌀 전분을 제조하고, 변성된 쌀 전분의 용해도, 팽윤력, RVA, DSC 특성을 연구하였다. 팽윤력은 일반 쌀 전분 보다 낮은 온도에서 증가되기 시작하였으나 높은 경향을 보였으며, 하이드록시프로필화 쌀 전분이 일반 쌀 전분보다 완만한 상승을 나타내었다. 용해도는 하이드록시프로필화 쌀 전분이 일반 쌀 전분보다 낮은 결과를 나타내었고 PO 함량이 높을수록 높아지는 결과를 보였다. RVA 분석결과 PO 함량이 높을수록 pasting temperature와 peak time이 낮아졌고 최고 점도는 하이드록시프로필화 쌀 전분이 일반 쌀 전분보다 낮고 holding strength는 높은 경향을 나타내고 breakdown의 경우 반응시간이 24시간이 20시간보다 낮은 경향을 보였으며 Setback은 24시간 반응시킨 처리구들이 일반 쌀 전분보다 낮은 것으로 나타났다. DSC분석결과 PO 함량이 높을수록 To, Tp, Tc, ${\Dalta}H$가 감소하였다. 따라서 하이드록시프로필화 쌀 전분의 경우 전분입자내의 intemal bond가 하이드록시프로필기에 의해 약해져서 호화가 쉽게, 즉 낮은 온도에서 일어나는 것으로 판단되었고 최대 팽윤력, breakdown에서 옥수수 전분과는 다른 결과를 나타내어 전분의 종류에 따라 같은 변성 처리라고 하더라도 다른 결과를 나타낼 수 있다는 사실이 확인되었다.

• 한국수소및신에너지학회논문집
• /
• 제29권6호
• /
• pp.627-634
• /
• 2018

Gallium-based liquid metal, e.g., eutectic gallium-indium (EGaIn), is highly attractive as an electrode material for flexible and stretchable devices. On the liquid metal, oxide layer is spontaneously formed, which has a wide band-gap, and therefore is electrically insulating. In this paper, we fabricate a capacitor based on eutectic gallium-indium (EGaIn) liquid metal and investigate its cyclic voltammetry (CV) behavior. The EGaIn capacitor is composed of two EGaIn electrodes and electrolyte. CV curves reveal that the EGaIn capacitor shows the behavior of electric double-layer capacitors (EDLC), where the oxide layers on the EGaIn electrodes serves as the dielectric layer of EDLC. The oxide thicker than the spontaneously-formed native oxide decreases the capacitance of the EGaIn capacitor, due to increased voltage loss across the oxide layer. The EGaIn capacitor without oxide layer exhibits unstable CV curves during the repeated cycles, where self-repair characteristic of the oxide was observed. Finally, the electrolyte concentration is optimized by comparing the CV curves at various electrolyte concentrations.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2012년도 추계총회 및 학술대회 논문집
• /
• pp.84-85
• /
• 2012

Poly(ethylene glycol) (PEG)는 Hydrophilic하면서 독성이 없기 때문에 약물과 관련된 연구가 많이 이루어졌다. 초기 PEGylation은 약물과 관련된 연구가 주를 이루었지만, 최근에는 PEG의 non-fouling 효과 때문에 표면에 적용하여 biomedical 장비에 세포나 단백질이 붙지 않도록 하는 개질하는 방법에 많은 연구가 진행되고 있다. Native Chemical Ligation(N.C.L.)은 단백질을 합성할 때, Protecting group을 사용하지 않고 반응을 진행시킬 수 있기 때문에 많은 주목을 받고 있다. N.C.L.은 합성한 두 물질이 Thioester와 Cysteine을 갖고 있으면, mild condition에서 amide bond를 형성하면서 반응이 쉽게 진행되기 때문에 다양한 분야에 적용할 수 있다. 이 논문에서 우리는 N.C.L.을 표면에 적용시켰으며 그 중 한 예로 표면 PEGylation진행하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
• /
• pp.193-195
• /
• 1988

The native oxide films were thermally and anodically formed on the n-GaP substrates grown by SSD method and measured this oxide thickness and the chemical composition and the electrical properties with formation condition. The chemical composition of themally oxidized GaP film was composed of mostly $GaPO_4$ at temperature below $800^{\circ}C$ and mostly $\beta-Ga_{2}O_{3}$ above $800^{\circ}C$. But The chemical composition of anodically oxidized GaPfilm was composed of the mixture of $Ga_{2}O_{3}$ and $P_{2}O_{5}$. The barrier height of Al/oxide/n-Gap which was formed at $700^{\circ}C$ by thermal oxidation method were 1.10eV, 1.03eV in Current-Voltage measurement. Interface charge density were $4{\times}10^{12}q(C/cm^2)$ and $3{\times}10^{12}q(C/cm^2)$ in Capacitance-Voltage measurement respectively.