• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.495-498
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• 2006

The influence of various process parameters for the as-deposited poly silicon was investigated. The polycrystalline silicon films were successfully deposited on glass substrates at a low-temperature $(<200^{\circ}C)$ using the catalytic chemical vapor deposition (Cat-CVD). We achieved a low hydrogen content $({\sim}0.9%)$ and a high deposition rate $({\sim}35{\AA}/sec)$. The film is applicable to thin film transistors on plastic substrates.

• 한국수소및신에너지학회논문집
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• 제7권2호
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• pp.173-180
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• 1996

4-probe resistivity measurement technique was used to study kinetics of hydrogen absorption-desorption on Pd film($520{\AA}$ thick) at room temperature upto 1 bar. Kinetics data are fitted well to 1st order kinetics equation in ${\alpha}$ and ${\alpha}^{\prime}$ phases. In ${\alpha}+{\alpha}^{\prime}$ phase, absorption kinetics was very complicated, but it could be explained partially with nucleation and growth process. Ln(dR/dt) vs. time plot gives rate constant k value(R is resistance of sample, t is time). k value for absorption is $4^{-6}{\times}10^{-4}/sec$ in ${\alpha}$ phase. k is increasing upto $4^{\times}10^{-2}/sec$ as hydrogen pressure increasing in ${\alpha}^{\prime}$ phase. k is proportional to ln(Pop/Peq), where Peq is equilibrium plateau pressure and Pop is the opposing pressure. In contrast to bulk sample k value was decreasing with increasing number of A-D cycling in ${\alpha}^{\prime}$ phase absorption.

• 제어로봇시스템학회논문지
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• 제13권7호
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• pp.616-623
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• 2007

A dual micro gas sensor array was fabricated using nano sized $SnO_2$ thin films which had good sensitivities to CO and combustible gases, or $H_2S$ gas for air quality sensors in automobile. The already existed air quality sensor detects oxidizing gases and reducing gases, the air quality sensor(AQS), located near the fresh air inlet detected the harmful gases, the fresh air inlet door/ventilation flap was closed to reduce the amount of pollution entering the vehicle cabin through HVAC(heating, ventilating, and air conditioning) system. In this study, to make $SnO_2$ thin film AQS sensor, thin tin metal layer between 1000 and $2000{\AA}$ thick was oxidized between 600 and $800^{\circ}C$ by thermal oxidation. The gas sensing layers such as $SnO_2$, $SnO_2$(pt) and $SnO_2$(+CuO) were patterned by metal shadow mask for simple fabrication process on the silicon substrate. The micro gas sensors with $SnO_2$(+Pt) and $SnO_2$(CuO) showed good selectivity to CO gas among reducing gases and good sensitivity to $H_2S$ that is main component of bad odor, separately.

• 한국세라믹학회지
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• 제32권8호
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• pp.881-892
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• 1995

Sol-Gel derived ferroelectric PZT thin films were fabricated on ITO/Glass substrate. Two kinds of rapid thermal annealing methods, R-I (six times of intermediate and final annealing) and R-II (one final annealing after six times of intermediate annealing) were used for preparation of multi-coated PZT thin films. 2500$\AA$-thick PZT thin films were obtained by the R-I and R-II methods and characterized by microstructure and dielectric properties. In case of using R-II, the microstructure was finer than that of R-I and there was no distinguishable difference in dielectric properties of PZT thin films between the R-I and R-II methods. But dielectric properties were enhanced by increasing perovskite phase fraction with increasing annealing temperature. Measured dielectric constant of PZT thin film annealed at 62$0^{\circ}C$ using the R-I method was 256 at 1kHz. Its remanant polarization (Pr) and coercive field (Ec) were 14.4$\mu$C/$\textrm{cm}^2$ and 64kV/cm, respectively.

• 한국세라믹학회지
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• 제33권10호
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• pp.1101-1108
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• 1996

No-doped PZT thin films have been fabricated on Pt/Ti/SiO2/Si substrate using Sol-Gel technique. A fast annealing metho (three times of intermediate and final annealing) was used for the preparation of multi-coated 1800$\AA$ thick Nb-doped PZT thin films. As Nb doping percent was increased leakage current was lowered approximately 2 order but dielectic properties were degraded due to the appearance of pyrochlore phase and domain pinning. Futhermore the increase of the final annealing temperature up to 74$0^{\circ}C$lowered the pyrochlore phase content resulting in enhancing the dielectric properties of the Nb doped films. The 3%-Nb doped PZT thin films with 5% excess Pb showed a capacitance density of 24.04 fF/${\mu}{\textrm}{m}$2 a dielectric loss of 0.13 a switchable polarization of 15.84 $\mu$C/cm2 and a coercive field of 32.7 kV/cm respectively. The leakage current density of the film was as low as 1.47$\times$10-7 A/cm2 at the applied voltage of 1.5 V.

• 한국전기전자재료학회논문지
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• 제15권12호
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• pp.1054-1059
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• 2002

A great deal of research has been done in the field of characterization for piezoelectric thin films after the first report on the measurement for the piezoelectric coefficient of thin films in 1990. The main idea of this research is to provide a distinctive solution for the measurement and standardization of both the longitudinal and the transverse piezoelectric d-coefficients, d33 and d31, of ferroelectric thin films. In general, to get these two coefficients of thin films, two different measuring systems are required. Here, we propose the improved method for the evaluation of these two coefficients with single equipment and with the relatively convenient procedure. The two-step loading process of applying the both positive and the negative pressure has been introduced to acquire the piezoelectric coefficients. These results have been calibrated for both the longitudinal and 4he transverse piezoelectric d-coefficients, d33 and 431, of thin films by comparison with the virtual standard created from FEM. In this experiments, we have obtained d33 of 331pC/N and 031 of -92.2pC/N for the PZT thin films.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 제5회 영호남 학술대회 논문집
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• pp.98-102
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• 2003

$Ba_2NaNb_5O_{15}$, hereafter BNN, thin films are attractive candidates for nonvolatile memory and electro-optic devices. In the present work, thin films that have different contents of Ba, Na and Nb have been prepared by H-MOD technique on silicon and Pt substrates. XRD and SEM were used to investigate the phase evolution behavior and the microstructure of the films. It was found that the films of about 450nm thick were crack-free and uniform in microstructure. Nb content strongly influenced the phase formation of the films, where low temperature phase was always formed at the stoichiometric BNN composition. However, the amount of low temperature phase decreased with the increase of excess Nb content, and the single phase (orthorhombic tungsten bronze structure) BNN thin film was obtained at the temperature as low as $750^{\circ}C$ for samples with excess niobium. From this study, the sub-solidus phase diagram below $850^{\circ}C$ for $BaO-Na_2O-Nb_2O_5$ ternary system is proposed.

• 한국전기전자재료학회논문지
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• 제19권6호
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• pp.538-546
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• 2006

We report on characteristics of specially designed inductively-coupled-plasma chemical vapor deposition (ICP-CVD) system for top-emitting organic light emitting diodes (TOLEDs). Using high-density plasma on the order of $10^{11}$ electrons/$cm^3$ generated by linear-type antennas connected in parallel and specially designed substrate cooling system, a 100 nm-thick transparent $SiN_{x}$ passivation layer was deposited on thin Mg-Ag cathode layer at substrate temperature below $50\;^{\circ}C$ without a noticeable plasma damage. In addition, substrate-mask chucking system equipped with a mechanical mask aligner enabled us to pattern the $SiN_x$ passivation layer without conventional lithography processes. Even at low substrate temperature, a $SiN_x$ passivation layer prepared by ICP-CVD shows a good moisture resistance and transparency of $5{\times}10^{-3}g/m^2/day$ and 92 %, respectively. This indicates that the ICP-CVD system is a promising methode to substitute conventional plasma enhanced CVD (PECVD) in thin film passivation process.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3304-3306
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• 1999

In this study, we used the sputtering method with single target to obtain the thick and uniform PZT($PbZrTiO_3$) films for micromached IR sensor application. Then, we investigated the etching characteristics and conditions which is necessary process to fabricate the IR sensor. We tested the C-axis orientation and P-E loop of the deposited PZT films with the XRD and RT66A, respectively. Also we investigated the surface of the films by the AFM and SEM analysis.

• 대한금속재료학회지
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• 제50권9호
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• pp.653-657
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• 2012

In this study, a molybdenum disilicide ($MoSi_2$) coating process was investigated by hydrogen reduction and Si-pack cementation. At first, the metallic Mo coating was carried out by hydrogen reduction of $MoO_3$ powder at $750^{\circ}C$ for various holding times (1, 2, 3 h) in hydrogen atmosphere. A $4.3{\mu}m$ thick metallic molybdenum thin film was formed at 3 h. $MoSi_2$ was obtained by Si-pack cementation on molybdenum thin film through hydrogen reduction processing. It was carried out using $Si:Al_2O_3:NH_4Cl=5:92:3$ (wt%) packs at $900^{\circ}C$ for various holding times (30, 60, 90 min) in Ar atmosphere. When the holding time was 90 min, a $MoSi_2$ layer was coated successfully and a $15.4{\mu}m$ thickness was observed.