• 한국전기전자재료학회논문지
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• 제25권9호
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• pp.681-685
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• 2012

We investigated the dry etching characteristics of TiN in $TiN/Al_2O_3$ gate stack using a inductively coupled plasma system. TiN thin film is etched by BCl3/He plasma. The etching parameters are the gas mixing ratio, the RF power, the DC-bias voltages and process pressures. The highest etch rate is in $BCl_3/He$ (25%:75%) plasma. The selectivity of TiN thin film to $Al_2O_3$ is pretty similar with $BCl_3/He$ plasma. The chemical reactions of the etched TiN thin films are investigated by X-ray photoelectron spectroscopy. The intensities of the Ti 2p and the N 1s peaks are modified by $BCl_3$ plasma. Intensity and binding energy of Ti and N could be changed due to a chemical reaction on the surface of TiN thin films. Also we investigated that the non-volatile byproducts such as $TiCl_x$ formed by chemical reaction with Cl radicals on the surface of TiN thin films.

• 한국세라믹학회지
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• 제32권8호
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• pp.915-921
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• 1995

The morphotropic phase boundary and phase transitions of the solid solutiion system, (1-x)(Na1/2Bi1/2)TiO3-PbTiO3＋xPbTiO3 were studied by investigating changes in crystal structure, variations in permittivity with temperature, and calorimetric behavior. It was observed that the morphotropic phase boundary (MPB) of this solid solutiion system was at near 14 mol% of PbTiO3. Compositions containing less than 10mol% PbTiO3 (x<0.1) exhibited a phase transition, i.e. ferroelectric rhombohedrallongrightarrowparaelectric paraelectric cubic, with increasing temperature. Composition containing more than 14 mol% PbTiO3 (x 0.14) showed a phase transition from ferroelectric tetragonal to paraelectric cubic. In the composition range of 0.1$\varepsilon$ (T) curve, which coincided with a phase transition from ferroelectric rhombohedral to an intermediate phase, was also found.

• 대한치과기공학회지
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• 제25권1호
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• pp.89-94
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• 2003

The use of titanium alloys as biomaterials is increasing due to their superior biocompatibility and enhanced corrosion resistance compared to conventional stainless steels and cobalt-based alloys. Ti-6Al-4V ($\alpha+\beta$type) alloy instead of pure titanium ($\alpha$type) is being widely used as biomaterials has some characteristics such as high fatigue strength, tensile strength and corrosion resistance. It also has similar characteristics to Ti in inducing bony ingrowth. But it has been reported recently that the vanadium element expresses cytotoxicity and carcinogenicity and the aluminium element is related with dementia of Alzheimer type and neurotoxicity. In order to overcome their detrimental effects, $\beta$-phase stabilizer Nb was chosen in the present study. CP-Ti(ASTM grade 2), Ti-3wt.%Nb($\alpha$type), Ti-20wt.%Nb ($\alpha+\beta$type) and Ti-40 wt.%Nb($\beta$type) alloys were melted by vacuum arc furnace. Biocompatibility of Ti-Nb alloys was evaluated by cytotoxicity test. The results can be summarized as follows: 1. For the cytotoxicity test, Ti-Nb alloys showed excellent biocompatibility compared to CP-Ti(ASTM grade 2), 316L STS and Co-Cr alloys.

• 한국지반환경공학회 논문집
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• 제11권10호
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• pp.33-39
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• 2010

산화피막 형성 기술(anodization)을 이용하여 나노크기의 $TiO_2$ 튜브가 표면에 내재된 자기 조직형(self-organized) 광감응 $TiO_2$ 금속막을 개발하였다. 개발된 $TiO_2$ 금속막의 특성은 EDX, SEM, XRD로 분석하였고, 전해질 성분과 농도 등에 따른 $TiO_2$ 나노튜브 형성 유무를 실험적으로 조사하였다. 광반응 특성을 보유한 아나타제형의 나노튜브가 성공적으로 내재된 것을 확인할 수 있었다. 휴믹산을 모델 유기물로 사용하여 광감응 $TiO_2$ 금속 분리막의 유기물 제거 특성을 실험적으로 검토하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1491-1493
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• 2002

The 0.5$Ba_2Ti_9O_{20}$-0.5Mg$TiO_3$ ceramics were prepared by the conventional mixed oxide method. The structural properties were investigated with sintering temperature by XRD. According to the X-ray diffraction patterns, major phases of the 0.5$Ba_2Ti_9O_{20}$-0.5Mg$TiO_3$ ceramics were coexisted. Also the secondary phase of Mg$Ti_2O_5$, Ba$Mg_6Ti_6O_{19}$ and the unreacted $TiO_2$ phase were existed. In the case of 0.5$Ba_2Ti_9O_{20}$-0.5Mg$TiO_3$ ceramics sintered $1350^{\circ}C$, dielectric constant, quality factor and temperature coefficient of resonant frequency were 33.7, 54,900GHz, -12.5ppm/$^{\circ}C$, respectively.

• 한국진공학회지
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• 제12권3호
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• pp.193-199
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• 2003

아크-마그네트론 복합 공정법에 의해 Cu, Ag 도핑된 TiN 나노 복합 화합물 박막을 합성하고 각 금속원소 종류 및 함량에 따른 기계적 특성 및 나노 구조로의 상변화 거동을 관찰하였다. 합성된 박막은 약 40 ㎬의 높은 경도치를 나타내었으며 2 at% 미만의 낮은 금속 원소 함량에서 최대 경도간을 나타내었다. 금속 원소 함량이 증가할수록 결정립 미세화 및 다결정화가 진행되어 초고경도 특성을 나타내는 나노구조 박막이 합성되었으며 도핑되는 금속원소 종류에 따라 나노 구조로의 상변화 기구가 상이함을 관찰하였다. TiN 박막내 도핑된 Cu는 Ti와 일부 결합을 이루면서 Ti의 자리를 치환하는 것으로 나타났으나, Ag는 Ti와 결합을 이루거나 Ti 격자 자리를 치환하는 것이 아니라 독립적으로 결정립계에 존재하여 charge transfer만을 발생시키는 것으로 관찰되었다.

• 열처리공학회지
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• 제2권4호
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• pp.11-18
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• 1989

To investigate the influence of $TiCl_4$, $N_2$ inlet fraction on the TiN layer, TiN film was deposited onto the STC3 and STD11 steel from gas mixtures of $TiCl_4/N_2/H_2$ by the radio frequency plasma assisted chemical vapor deposition. The films were deposited at various $TiCl_4$, $N_2$ inlet fractions. The results showed that the film thickness was increased with $TiCl_4$ inlet fraction. However, while the thickness was increased with $N_4$ inlet fraction under 0.4 the thickness was decreased with increasing $N_2$ inlet fraction over 0.4. The density of deposited films was varied as $TiCl_4$, $N_2$ inlet fraction and its maximum value was about $5.6g/cm^3$. The contents of chlorine were increased with increasing $TiCl_4$ inlet fraction and nearly constant with increasing $N_2$ inlet fraction.

• 한국재료학회지
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• 제14권12호
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• pp.829-834
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• 2004

Annealing of $Cu(B)/Ti/SiO_2$ in vacuum has been carried out to investigate the effects of Ti underlayer on microstructure in $Cu(B)/Ti/SiO_2$ structures. For comparison, $Cu(B)/Ti/SiO_2$ structures was also annealed in vacuum. Three different temperature dependence of Cu growth can be seen in $Cu(B)/Ti/SiO_2$; B precipitates- pinned grain growth, abnormal grain growth, normal grain growth. The Ti underlayer having a strong affinity for B atoms reacts with the out-diffused B to the Ti surface and forms titanium boride at the Cu-Ti interface. The formation of titanium boride acts as a sink for the out-diffusion of B atoms. The depletion of boron in grain boundaries of Cu films, as results of the rapid diffusion of B along the grain boundaries and the insufficient segregation of B to the grain boundaries, induces grain boundaries to migrate and causes the abnormal grain growth. The increased bulk diffusion coefficient of B within Cu grains can be responsible for the normal grain growth occurring in the annealed $Cu(B)/Ti/SiO_2\;at\;600^{\circ}C$. In contrast, the $Cu/SiO_2$ structures show only the abnormal growth of grains and their sizes increasing as the temperature increases above $400^{\circ}C$.

• 한국재료학회지
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• 제9권9호
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• pp.900-904
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• 1999

TiO$_2$분말을 $Al_2$O$_3$분말에 대하여 무게비로 1,3,5,7,9와 11wt%로 혼합하여 알루미나 세라믹스의 미세조직 및 기계적 물성변화를 관찰하였다. TiO$_2$분말의 첨가량이 증가할수록 부피비중은 3.26에서 2.90g/㎤으로 감소하였으며 기공율은 TiO$_2$분말의 첨가량이 7wt%까지는 감소하였으나 9wt%이상 첨가할 경우 증가하였다. 압축강도 측정 결과 파괴강도는 TiO$_2$분말의 첨가량이 7wt%까지는 증가하였으나 9wt%이상 첨가할 경우 감소하였다. 3점 곡강도를 측정한 결과 최대 파괴 응력 값은 TiO$_2$분말의 첨가량이 증가할수록 감소하였다.

• 한국재료학회지
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• 제14권6호
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• pp.432-435
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• 2004

Ti and Ti alloys are important materials for medical and dental applications. The effect of equal channel angular process(ECAP) and addition of Fe in Ti were studied with optical microstructure and corrosion behavior. Fine grains in Ti was obtained after ECAP. Corrosion behavior of commercial pure(CP)-Ti and Ti alloys was studied by open circuit test and polarization curve test(PCT) at $36.5^{\circ}C$ with SBF in biological environment. The corrosion behavior of ECAP-Ti was similar to that of CP-Ti in PCT, but Ti-Fe alloys were observed to become more corrosive with increasing Fe content.