• Tribology and Lubricants
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• 제38권6호
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• pp.274-280
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• 2022

There is a problem that semiconductor probe pin has a short lifespan. In order to solve this problem, Ti having excellent conductivity was doped to tetrahedral amorphous carbon (ta-C) having excellent hardness and abrasion resistance. This experiment was planned through the Taguchi robust design to determine the effect of the control factor of the ta-C:Ti coating film. The effect and contribution of control factors such as Unbalanced Magnetron Sputter(UBM) discharge current, arc discharge current, temperature, and bias voltage on ta-C:Ti characteristics were analyzed from the perspective of electrical and mechanical characteristics. The UBM discharge current was set to 4, 6, and 8 A. The main control factor of thickness and resistance is the UBM discharge current, and the thickness increased and the resistance decreased as the current increased. The decrease in resistance is due to the increase in the Ti content of the ta-C:Ti coating film. The arc discharge current was set to 60, 80, and 100 A. The main control factor of hardness and wear is the arc discharge current, and as the current rises, the hardness increases and the wear area decreases. This is due to the increased ta-C content of the ta-C:Ti coating film. Since resistance and wear are important for Probe Pin, the optimal level is set from the perspective of resistance and wear and a confirmation experiment is conducted.

• 한국분말재료학회지
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• 제13권1호
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• pp.10-17
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• 2006

Model experiment was introduced to obtain the formation of a core/rim structure by only liquid phase reaction in Ti(C, N)-based cermet alloys. Infiltrated Ti(C, N)-Ni, $MO_2C-Ni$, and TaC-Ni cermets were bonded to sandwiched specimen by heat treatment $1450^{\circ}C$ for 5hr. With nitrogen addition, both (Ti, Mo) (C, N) and (Ti, Ta) (C, N) rim structure was nucleated around comer of cuboidal Ti(C, N) core. However, equilibrium shapes of(Ti, Mo) (C, N) and (Ti, Ta) (C, N) rim were different possibly due to the effect of interface energy. The core/rim and rim! binder interfaces were parallel to each other with TaC addition, while rotated to each other with $MO_2C$ addition.

• 한국세라믹학회지
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• 제38권10호
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• pp.881-885
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• 2001

Kinetics and mechanisms of intermediate phases formation in $Ba(Mg_{1/3}Ta_{2/3})O_3$, obtained by a solid state reaction were studied. $Ba{Ta_2}{O_6}$ and ${Ba_4}{Ta_2}{O_9}$ as intermediate products were first formed at $700^{\circ}C$. $Ba(Mg_{1/3}Ta_{2/3})O_3$ was appeared at $800^{\circ}C$. Several reactions take place on heating process. $Ba{Ta_2}{O_6}$ is found at the first stage of the reaction, and then $Ba{Ta_2}{O_6}$ or ${Ba_4}{Ta_2}{O_9}$ react with MgO to form $Ba(Mg_{1/3}Ta_{2/3})O_3$. The reaction of $Ba(Mg_{1/3}Ta_{2/3})O_3$ formation does not complete until fired at $1350^{\circ}C$ for 60 min. The kinetics of solid-state reaction between powdered reactants was controlled by diffusion mechanism, and can be explained by the Jander's model for three-dimensional diffusion.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1502-1504
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• 2003

최근 전자기기의 경박단소화 추세는 전자기기의 크기와 가격의 감소를 이끌었으며 이러한 추세는 앞으로 지속될 것이다. 이와 같은 현상으로 전자기기를 구성하는 요소의 절반이상을 차지하는 단위수동소자의 경우 소형화를 넘어 박막화 및 집적화가 절실히 요구되는 실정이다. 따라서 본 연구에서는 현재 GHz 대역의 휴대용 무선통신 송 수신부 등에 사용되고 있는 기판이 $Al_2O_3$ 기판인 점을 고려하여 기판의 공통화를 위해 $Al_2O_3$ 기판 위에 Ta/$Ta_2O_5$/Ta 구조를 갖는 MIM 박막커패시터를 제작하여 그 특성을 고찰하였다. 모든 박막의 증착은 RF-magnetron reactive sputtering법에 의해 이루어졌으며, 유전체 열처리는 $700^{\circ}C$ 진공상태에서 60 sec 동안 수행하였다. XRD 분석결과, as-deposited $Ta_2O_5$ 박막은 열처리 후에 비정질상에서 결정질상으로 변환되었다. Ta/$Ta_2O_5$/Ta/Ti/$Al_2O_3$ 커패시터의 전기적 특성으로는 C-F, C-V, I-V 를 측정하였다.

• 한국재료학회지
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• 제4권7호
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• pp.759-766
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• 1994

본 연구에서는 Ta 박막 밑에 $SnO_{2}$박막층을 입혀서 $Ta/SnO_2$이중박막이 산화될 때 산소의 공급원을 2원화 함으로써 $Ta_2O_5$의 stoichiomitry를 향상시켜 $Ta_2O_5$박막 커패시터의 주설전류를 줄이고자 하였다. Tantalum을 실리콘 웨이퍼 위에 기판온도를 변화시켜 가면서 전자빔증착이나 스퍼터링 방밥으로 입히고 $500^{\circ}C$~$900^{\circ}C$에서 산화시켜 Al/$Ta_2O_5$p-Si/Al또는Al/$Ta_2O_5$/p-Si/Al과 같은 MIS형 커패시터를 만들어 유전상수 및 누설전류를 측정하였으며 XRD, AES, ESCA등을 이용하여 박막의 결정성 및 특성을 분석하였다. $SnO_{2}$박막층을 입힌 커패시터는$SnO_{2}$층을 입히지 않은 커패시터보다 10배 이상 큰 200정도의 유전상수 값을 나타내었다. 그리고 산화온도가 높으면 박막의 결정화로 인하여 유전상수는 증가하지아는 누설전류도 약간 증가하는 것이 확인되었다. 또한 높은 증착온도는 일반적으로 누설전류를 낮추는 것으로 나타났다. 특히 $SnO_{2}$층을 입힌 경우에 기판온도를 $200^{\circ}C$로 하고 $800^{\circ}C$에서 산화시켜 만든 커패스터의 경우에 $4 \times 10^{5}$V/cm의 전장강도에서 $10^{-7}A/\textrm{cm}^2$의 낮은 누설전류 값을 나타내었다. $Ta_2O_5$박막은 $700^{\circ}C$ 이상에서 박막이 결정되고, Ta /$SnO_{2}$ 이중박막을 산화시키면 처음에는 Ta박막과 $SnO_{2}$박막 계면에서 $SnO_{2}$로부터 Ta박막에 산소가 공급되지마는 점차 Sn이 Ta박막쪽으로 확산되어 결국에는 Ta-Sn-O계의 새로운 ternary oxide가 생성되는 것으로 나타났다.

• 한국자기학회지
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• 제10권6호
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• pp.280-294
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• 2000

RF-DC 마그네트론 스퍼터링을 이용하여 5$\times$$10^{-3}$ Torr의 알곤 가스 분위기에서 [(300nm)Ta/(500nm)NdFeB/(300nm)Ta] 영구자석 박막을 제조한 후 이의 미세구조 및 자기특성을 조사하였다 650-75$0^{\circ}C$로 가열된 Si 기판위에 성막한 [Ta/ NdFeB/Ta] 박막은 수직자기이방성과 함께 우수한 경자기특성을 나타내었으며, 특히 기판온도 $650^{\circ}C$와 $700^{\circ}C$에서 제조된 박막은 막면에 수직한 방향으로 각각 20 MGOe의 최대자기에너지적과 18.9 kOe의 큰 고유보자력을 나타내었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1420-1421
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• 2006

In this study, structural and micowave dielectric properties of the $Mg_{5}B_{4}O_{15}$ (B=Ta, Nb) cation-deficient perovskite ceeramics. The specimens are prepared through the solid-state route. According to the XRD pattern, $Mg_{4}Ta_{2}O_9$ and $MgTa_{2}O_6$ phase exist in calcined and sintered $Mg_{5}Ta_{4}O_{15}$ powder. Also $Mg_{5}Ta_{4}O_{15}$ phase added with increasing sintering temperature. In the case of calcined and sintered $Mg_{5}Nb_{4}O_{15}$ powder, single phase of $Mg_{5}Nb_{4}O_{15}$ were appeared. The bulk density and quality factor of the $Mg_{5}B_{4}O_{15}$ (B=Ta, Nb) ceramics were increased with sinteming temperature in $1400^{\circ}C{\sim}1450^{\circ}C$, but these were decreased in another sintering temperature. Dielectric constant of the $Mg_{5}Ta_{4}O_{15}$ ceramics was increased continuously with increasing of sintering temperature. And the dielectric constant of the $Mg_{5}Nb_{4}O_{15}$ ceramics was increased in $1400^{\circ}C{\sim}1450^{\circ}C$ but decreased in $1475^{\circ}C$. In the case of the $Mg_{5}Ta_{4}O_{15}$ and $Mg_{5}Nb_{4}O_{15}$ ceramics sintered at $1450^{\circ}C$ for 5h, the dielectric constant, quality factor, and temperature coefficient of the resonant frequency (TCRF) were 8.2, 259,473 GHz, -10.91 $ppm/^{\circ}C$ and 14, 37,350 GHz, -52.3 $ppm/^{\circ}C$, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.578-581
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• 1999

The Co-Cr-Ta films are one of the most suitable candidates for perpendicular magnetic recording media. The facing targets sputtering(FTS) system has a advantage of preparing films over a wide range of working gas pressure on plasma-free substrates. In this study, we investigated the effect underlayers on the growths layers of Co-Cr-Ta recording layers. The Co-Cr-Ta/Ti(CoCr) double layers were deposited with sputter gas pressure$(P_N, 0.3-1mTorr)$ by using FTS apparatus at temperature of$40^{\circ}C~-300^{\circ}C$, respectively. Crystallographic and magnetic characteristics were evaluated by x-ray diffractometry(XRD) and vibrating sample magnetometer(VSM), respectively.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.24.1-24.1
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• 2009

Tantalum carbo-nitride($T_aC_xN_y$) films were deposited with chemical vapor deposition(CVD) using tert-butylimido tris-diethylamido tantalum (TBTDET, $^tBu-N=Ta-(NEt_2)_3$, $Et=C_2H_5$, $^tBu=C(CH_3)_3$) between $350^{\circ}C$ and $600^{\circ}C$ with argon as a carrier gas. Fourier transform infrared (FT-IR)spectroscopy was used to study the thermal decomposition behavior of TBTDET in the gas phase. When the temperature was increased, C-H and C-N bonding of TBTDET disappeared and the peaks of ethylene appeared above $450^{\circ}C$ in the gas phase. The growth rate and film density of $T_aC_xN_y$ film were in the range of 0.1nm/min to 1.30nm/min and of $8.92g/cm^3$ to $10.6g/cm^3$ depending on the deposition temperature. $T_aC_xN_y$ films deposited below $400^{\circ}C$ were amorphous and became polycrystal line above $500^{\circ}C$. It was confirmed that the $T_aC_xN_y$ film was a mixture of TaC, graphite, $Ta_3N_5$, TaN, and $Ta_2O_5$ phases and the oxide phase was formed from the post deposition oxygen uptake. With the increase of the deposition temperature, the TaN phase was increased over TaC and $Ta_3N_5$ and crystallinity, work function, conductivity and density of the film were increased. Also the oxygen uptake was decreased due to the increase of the film density. With the increase of the TaC phase in $T_aC_xN_y$ film, the work function was decreased to 4.25eV and with the increase of the TaN phase in $T_aC_xN_y$ film,it was increased to 4.48eV.

• Tribology and Lubricants
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• 제32권4호
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• pp.125-131
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• 2016

In recent years, thick ta-C coating has attracted considerable interest owing to its existing and potential commercial importance in applications such as automobile accessories, drills, and gears. The thickness of the ta-C coating is an important parameter in these applications. However, the biggest problems are achieving efficient coating and uniformity over a large area with high-speed deposition. Feasibility is confirmed for the ta-C coating thickness of up to 9.0 µm (coating speed: 3.0 µm/h, fixed substrate) using a single FCVA cathode. The thickness was determined using multiple coating cycles that were controlled using substrate temperature and residual stresses. In the present research, we have designed a coating system using FCVA plasma and produced enhanced thick ta-C coating. The system uses a specialized magnetic field configuration with stabilized DC arc plasma discharge during deposition. To achieve quality that is acceptable for use in automobile accessories, the magnetic field, T-type filters, and 10 pieces of a multi-cathode are used to demonstrate the deposition of the thick ta-C coating. The results of coating performance indicate that uniformity is ±7.6 , deposited area is 400 mm, and the thickness of the ta-C coating is up to 5.0 µm (coating speed: 0.3 µm/h, revolution and rotation). The hardness of the coating ranges from 30 to 59 GPa, and the adhesion strength level (HF1) ranges from 20 to 60 N, depending on the ta-C coating.