• Journal of the Korean Vacuum Society
• /
• v.17 no.5
• /
• pp.466-472
• /
• 2008

Purple Gold is the alloy consisting of 78wt%Au-22wt%Al, and is expressed as a chemical formula, $AuAl_2$. Lately it is being used for the material of accessories or the decorative ornaments, being one of the colored golds having the peculiar purple color, like White Gold and Pink Gold. Purple Gold has the weak point in shaping through casting process due to the bad malleability and castability, being the intermetalic compound of Au and Al. Therefore, it is possible to produce the final product only by the cutting and the grinding process or to use it as a decorative coat with the thin film evaporation. This study implemented two kinds of thin film experiments. One is the case that heat treatment was made after Au and Al deposition evaporated separately with a weight ratio 78:22 on the 200nm$SiO_2$/Si substrate. The other is the case that the surface deposition was made through the vacuum evaporation, keeping the glass substrate temperature remain room temperature, using the bulk $AuAl_2$ as a source. The final film property was measured, focusing on the Purple Gold's color and thickness through the bare eye inspection, the microstructure analysis, the surface resistance analysis, the color difference analysis, and XRD analysis. Purple Gold was not formed, as the excessive surface agglomeration occurred, in case of being produced and treated thermally with 12.5nmAu/40nmAl/200nm$SiO_2$/Si structure. Our results suggest that of Purple Gold films, showing the same purple color as the bulk's, were successfully deposited with the direct thermal evaporation from the $AuAl_2$ bulk source.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.12
• /
• pp.1091-1098
• /
• 1998

Thermal stability of the electroless deposited Cu thin film was investigated. Cu/TaN/Si multilayer was fabricated by electroless-depositing Cu thin layer on TaN diffusion barrier layer which was deposited by MOCVD on the Si substrate, and was annealed in $H_2$ ambient to investigate the microstructure of Cu film with a post heat-treatment. Cu thin film with good adhesion was successfully deposited on the surface of the TaN film by electroless deposition with a proper activation treatment and solution control. Microstructural property of the electroless-deposited Cu layer was improved by a post-annealing in the reduced atmosphere of $H_2$ gas up to $600^{\circ}C$. Thermal stability of Cu/TaN/Si system was maintained up to $600^{\circ}C$ annealing temperature, but the intermediate compounds of Cu-Si were formed above $650^{\circ}C$ because Cu element passed through the TaN layer. On the other hand, thermal stability of the Cu/TaN/Si system in Ar ambient was maintained below $550^{\circ}C$ annealing temperature due to the minimal impurity of $O_2$ in Ar gas.

• Journal of the Korean Ceramic Society
• /
• v.41 no.11
• /
• pp.797-803
• /
• 2004

The heat generation tests of SiC and MO$_2$ samples by use of a microwave heating system were carried out and UO$_2$+5 wt% CeO$_2$ pellets were sintered in a microwave furnace in an oxidizing atmosphere, by taking into account the characteristics of the microwave heating obtained from the heat generation tests. The characteristics of pellets sintered in a microwave furnace were analysed and compared with those of the pellets sintered in a conventional electrical furnace. The temperature of MO$_2$ pellets with microwave heating increased quickly with input power and the variation of output power depended on the reaction characteristics of SiC and MO$_2$ with microwave. The sintered density of UO$_2$+5wt% CeO$_2$ pellets sintered in the microwave furnace was lower about 2% T.D. than that of the pellets sintered in an electrical furnace with sintering parameters. The microstructure of pellets sintered in microwave furnace has a broader pore distribution but has a larger grain size than that of the pellets sintered in the electrical furnace.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.30 no.10
• /
• pp.646-650
• /
• 2017

We have evaluated the ferroelectric and electrical properties of pure $BiFeO_3$ (BFO) and $Bi_{0.9}A_{0.1}Fe_{0.975}V_{0.025}O_{3+{\alpha}}$ (A=Nd, Tb) thin films on $Pt(111)/Ti/SiO_2/Si(100)$ substrates by using a chemical solution deposition method. The remnant polarization ($2P_r$) of the $Bi_{0.9}Tb_{0.1}Fe_{0.975}V_{0.025}O_{3+{\alpha}}$ (BTFVO) thin film was approximately $65{\mu}C/cm^2$, with a maximum applied electric field of 950 kV/cm and a frequency of 10 kHz, where as that of the $Bi_{0.9}Nd_{0.1}Fe_{0.975}V_{0.025}O_{3+{\alpha}}$ (BNFVO) thin film was approximately $37{\mu}C/cm^2$ with a maximum applied electric field of 910 kV/cm. The leakage current density of the co-doped BNFVO thin film was four orders of magnitude lower than that of the pure BFO thin film, at $2.75{\times}10^{-7}A/cm^2$ with an applied electric field of 100 kV/cm. The grain size and uniformity of the co-doped BNFVO and BTFVO thin films were improved, in comparison to the pure BFO thin film, through structural modificationsdue to the co-doping with Nd and Tb.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.2
• /
• pp.303-310
• /
• 2008

We fabricated hydrogenated amorphous silicon(a-Si:H) 140 nm thick film on a $180\;nm-SiO_2/Si$ substrate with an inductively-coupled plasma chemical vapor deposition(ICP-CVD) equipment at $250^{\circ}C$. Moreover, 30 nm-Ni film was deposited with a thermal-evaporator sequently. Then the film stack was annealed to induce silicides by a rapid thermal annealer(RTA) at $200{\sim}500^{\circ}C$ in every $50^{\circ}C$ for 30 minuets. We employed a four-point tester, high resolution X-ray diffraction(HRXRD), field emission scanning electron microscope(FE-SEM), transmission electron microscope(TEM), and scanning probe microscope(SPM) in order to examine the sheet resistance, phase transformation, in-plane microstructure, cross-sectional microstructure evolution, and surface roughness, respectively. We confirmed that nano-thick high resistive $Ni_3Si$, mid-resistive $Ni_2Si$, and low resistive NiSi phases were stable at the temperature of <300, $350{\sim}450^{\circ}C$, and >$450^{\circ}C$, respectively. Through SPM analysis, we confirmed the surface roughness of nickel silicide was below 12 nm, which implied that it was superior over employing the glass and polymer substrates.

• Journal of Korea Foundry Society
• /
• v.28 no.1
• /
• pp.20-24
• /
• 2008

The characteristics, such as roughness, thickness, microhardness and corrosion resistance, of plasma electrolytic oxide coatings on AZ91D alloy were investigated under the processing condition of various coating times. The coatings on AZ91D alloy consisted of MgO, $MgAl_{2}O_{4}$ and $Mg_{2}SiO_{4}$ oxides. The surface roughness and thickness of coatings became larger with increasing the coating time. The microhardness in cross section of coatings was much higher than not only that in surface but that in the conventional anodic oxide coatings, which increased progressively as the coating time increased. After being immersed in 3.5%NaCl solution and methyl alcohol, the corrosion resistance of AZ91D alloy was markedly improved by plasma electrolytic oxidation coating treatment, and the AZ91D alloy coated for 50min revealed excellent corrosion resistance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.05b
• /
• pp.106-109
• /
• 2005

The $(Sr_{1-x}Ca_x)TiO_3$(SCT) thin films are deposited on Pt-coated electrode (Pt/TiN/$SiO_2$/Si) using RF sputtering method with substitutional contents of Ca. The optimum conditions of RF power and Ar/$O_2$ ratio were 140[W] and 80/20, respectively. Deposition rate of SCT thin film was about 18.75[$\AA$/min]. The dielectric constant was increased with increasing the substitutional contents of Ca, while it was decreased if the substitutional contents of Ca exceeded over 15[mol%]. The capacitance characteristics had a stable value within ${\pm}4$[%] in temperature ranges of -80~+90[$^{\circ}C$].

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.31 no.4
• /
• pp.226-230
• /
• 2018

Pure $BiFeO_3$ (BFO) and codoped $Bi_{0.9}A_{0.1}Fe_{0.975}Zn_{0.025}O_{3-{\delta}}$ (A=Eu, Dy) thin films were prepared on Pt(111)/Ti/$SiO_2$/Si(100) substrates by chemical solution deposition. The remnant polarizations (2Pr) of the $Bi_{0.9}Eu_{0.1}Fe_{0.975}Zn_{0.025}O_{3-{\delta}}$ (BEFZO) and $Bi_{0.9}Dy_{0.1}Fe_{0.975}Zn_{0.025}O_{3-{\delta}}$ (BDFZO) thin films were about 36 and $26{\mu}C/cm^2$ at the maximum electric fields of 900 and 917 kV/cm, respectively, at 1 kHz. The codoped BEFZO and BDFZO thin films showed improved electrical properties, and leakage current densities of 3.68 and $1.21{\times}10^{-6}A/cm^2$, respectively, which were three orders of magnitude lower than that of the pure BFO film, at 100 kV/cm.

• Korean Journal of Materials Research
• /
• v.3 no.1
• /
• pp.12-18
• /
• 1993

Abstract The effect of the film stress on the thermal stability of TiSi, films under the dielectric overcoat was investigated. TiS$i_2$ films with the sheet resistance of 1.2 ohm/sq. were produced by a solid-state reaction between sputtered Ti film and single-crystalline Si in an RTA (rapid thermal anneal) machine. Dielectric overcoats such as the USG (Undoped Silicate Glass, Si$O_2$) film and the PE-SiN(S$i_3$$N_4$) film were deposited by AP-CVD and PE-CVD, respectively, on the TiS$i_2$ film. The thermal stability of the TiSi, film was evaluated by changes in the sheet resistance, film stress and microstructure after furnace anneals at 90$0^{\circ}C$. Agglomeration of the TiSi2 film high temperatures results in the increase of sheet resistance and the decrease of tensile stress of TiSi, film. The stress level of the TiSi" PE-SiN and ~SG films at 90$0^{\circ}C$C was 1.3${\times}{10^{9}}$, 1.25 ${\times}{10^{10}}$, 2.26 ${\times}{10^{10}}$ dyne/c$m^2$ in tensile, respectively. Dielectric films deposited by CVD on TiSi, was effective on preventing agglomeration of TiSi,. The PE-SiN film mproved the thermal stability of TiSi, more effectively than the AP-CVD USG film. It is considered that agglomeration of the TiS$i_2$ film under the stress of dielectric overcoat at high temperature can be caused by a diffusional flow of atom called Nabarro-Herring microcreep.reep.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.11
• /
• pp.984-989
• /
• 1998

The ($Sr_{1-x}Ca_x)TiO_3$(SCT) thin films are deposited on Pt-coated electrode($Pt/TiN/SiO_2/Si$) using RF sputtering method with substitutional contents of Ca. The maximum grain of thin films is obtained by substitution of Ca at 15[mol%]. All SCT thin films had (111) preferred orientation. The dielectric constant was increased with increasing the substitutional contents of Ca, while it was decreased if the substitutional contents of Ca exceeded over 15[mol%]. The dielectric constant changes almost linearly in temperature ranges of -80~+90[$^{\circ}C$]. The temperature properties of the dielectric loss have a stable value within 0.02 independent of the substitutional contents of Ca. All SCT thin films used in this study show the phenomena of dielectric relaxation with the increase of frequency, and the relaxation frequency is observed above 200[kHz].