• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.175-176
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• 2007

This paper describes on the characteristics of Pd thin films deposited on poly-crystalline 3C-SiC buffer layers for microsensors, in which the poly 3C-SiC was grown on Si, $SiO_2$, and AlN substrates, respectively, by APCVD using HMDS, $H_2$, and Ar gas at $1100^{\circ}C$ for 30 min. In this work, a Pd thin film was deposited on the poly 3C-SiC film by RF magnetron sputter. The thickness, uniformity, and quality of these samples were evaluated by SEM. Crystallinity and orientation of the Pd film were analyzed by XRD. Finally, Pd/poly 3C-SiC schottky diodes were fabricated and characterized by current-voltage measurements. From these results, Pd/poly 3C-SiC devices are promising for high temperature hydrogen sensors and other microsensors.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.259-260
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• 2006

Effects of Rb doping on the aging characteristics have been studied in SrS:Ce thin film electroluminescence (EL) devices. It has been found that a luminance saturation and decrease of an EL efficiency are suppressed by Rb doping. For the SrS:Ce,Rb device, a luminance and an efficiency after 1024 h of aging at 1 kHz drive maintain at about 70% and 80% of the initial values, respectively.

• Journal of Powder Materials
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• v.8 no.3
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• pp.201-206
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• 2001

$>LaMnO_3$$(La, Sr)MO_3$, and $(La, Sr)MO_3/YSZ$ gel films were deposited by spin-coating technique on scandium-doped zirconia (YSZ) substrate using the precursor solution prepared from $La(O-i-C_3H_7)_3$, $Co(CH_3COO)_2$or $Mn(O-i-C_3H_7)_2$,2-methoxyethanol, and polyethylene glycol. By heat-treating the gel films, the electrochemical cells, $(La, Sr)MnO_3{\mid}ScSZ{\mid}Pt$ were fabricated. The effect of polyethylene glycol on the microstructure evolution of $$LaCoO_3and $LaMnO_3$thin films was investigated, and NOx decomposition characteristics of the electrochemical cells were investigated at $500^{\circ}C$ to $600^{\circ}C$. By applying a direct current to the $(La, Sr)MnO_3{\mid}ScSZ{\mid}Pt$ electrochemical cell, good NOx conversion rate could be obtained relatively at low current value even if excess oxygen is included in the reaction gas mixture.

• Journal of Magnetics
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• v.15 no.4
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• pp.169-172
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• 2010

The coercivity mechanism in permanent magnets was analyzed according to the effects of domain nucleation and domain wall pinning. The coercivity mechanism of a TbCo thin film with high perpendicular magnetic anisotropy was considered in terms of the local inhomogeneity in the thin film. The initial magnetization curves of the TbCo thin films demonstrated domain wall pinning to be the main contributor to the coercivity mechanism than domain nucleation. Based on the coercivity model proposed by Kronmuller et al., the inhomogeneity size acting as a domain wall pinning site was determined. Using the measured values of perpendicular anisotropy constant ($K_u$), saturation magnetization ($M_s$), and coercivity ($H_c$), the inhomogeneity size estimated in a TbCo thin film with high coercivity was approximately 9 nm.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.12
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• pp.1008-1015
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• 2002

The fabricated La-modified lead titanate (PLT) thin film without poling treatment was investigated for modulation frequency dependence of pyroelectric properties by the dynamic method. $Pb_{l-x}La_{x}Ti_{l-x/4}O_3$(x=0.1) (PLT(10)) thin film haying 10 mol% La content was deposited on a Pt/$TiO_{x}$/$SiO_2$/Si substrate by sol-gel method. The PLT(10) thin film exhibits a relatively excellent dielectric property. The pyroelectric coefficient (p) of the PLT(10) thin film is 6.6 x $10^{-9}C$$textrm{cm}^2$$.$K without frequency dependence. The figure of merits for the voltage responsivity and specific detectivity are 1.03 x $10^{-11}C$.cm/J and 1.46 x $10^{-10}C$.cm/J, respectively The PLT(10) thin film has voltage responsivity (RV) of 5.IS V/W at 8 Hz. Noise equivalent power (NEP) and specific detectivity ($D^{*}$) of the PLT(10) thin film are 9.93 x $10^{-8}$W/$Hz^{1/2}$ and 1.81 x $10^{6}$cm.$Hz^{1/2}$/W at the same frequency of 100 Hz,, respectively The results means that PLT thin film having 10 mol% La content is suitable for the sensing materials of pyroelectric IR sensors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.194-195
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• 2006

Aluminum oxide films directly grown on n-type 6H-SiC(0001) substrates were fabricated by RF magnetron sputtering system. Metal-insulator-semiconductor(MIS) C-V properties with aluminum oxide thin films showed hysteresis and f1at band voltage shift. The dielectric constant of the film calculated from the capacitance at the accumulation region was about 5. Typical gate leakage current density of film at room temperature was the order of $10^{-9}\;A/cm^2$ at the range of within 2MV/cm. The breakdown did not occur at the film within the measurement range.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.05a
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• pp.53-53
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• 2003

Plasma polymerized organic thin films were deposited on Si(100) glass and metal substrates using thiophene and ethylcyclohexane precursors by PECVD method. In order to compare electrochemical properties of the as-grown thin films, the effects of the RF plasma power in the range of 30~100 W. AFM showed that the polymer films with smooth surface and sharp interface could be grown under various deposition conditions. Impedance analyzer was utilized for the determination of I-V curve for leakage current density and C-V for dielectric constants, respectively. To obtain C-V curve, we used a MIM structure of metal(Al)-insulator(plasma polymerized thin film)-metal(Pt) structure. Al as the electrode was evaporated on the thiophene films that grew on Pt coated silicon substrates, and the dielectric constants of the as-grown films were then calculated from C- V data measured at 1MHz. From the electrical property measurements such as I-V and C-V characteristics, the minimum dielectric constant and the best leakage current of thiophene thin films were obtained to be about 3.22 and $1{\;}{\times}10^{-11}{\;}A/cm^2$. However, in case of ethylcyclohexane thin films, the minimum dielectric constant and the best leakage current were obtained to be about 3.11 and $5{\;}{\times}10^{-12}{\;}A/cm^2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05d
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• pp.57-60
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• 2003

Electro-Optical (EO) performances for the ion beam (IB) aligned twisted-nematic (TN)-liquid crystal display (LCD) with ion beam exposure on the new of diamond like carbon (DLC) thin film surface were investigated. Voltage-transmittance (V-T) curve and response time without backflow bounce in the ion beam aligned TN-LCD with ion beam exposure for 0.5 and 1min on the DLC thin film was observed. Also. the fast response time of ion beam aligned TN-LCD with ion beam exposure for 1min on the DLC thin film surface can be achieved. The residual DC voltage of the ion beam aligned TN-LCD on the DLC thin film surface was almost the same as that of the rubbing aligned TN-LCD on the polyimide(PI) surface.

• The Korean Journal of Ceramics
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• v.6 no.2
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• pp.129-133
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• 2000

Boron nitride films were synthesized with $N_2$ion flux of low energy, up to 100 eV, at different substrate temperatures of no heating, 200, 400, 500, and $800^{\circ}C$, respectively. Boron was supplied by e-beam evaporation at the rate of $1.5\AA$/sec. For all the conditions, hexagonal BN (h-BN) phase was mainly synthesized and high resolution transmission electron microscopy (HRTEM) showed that (002) planes of h-BN phase were aligned vertical to the Si substrate. The maximum alignment occurred around $400^{\circ}C$. In addition to major h-BN phase, transmission electron diffraction (TED) rings identified the formation of cubic BN (c-BN) phase. But HRTEM showed no distinct and continuous c-BN layer. These results suggest that c-BN phase may form in a scattered form even when h-BN phase is mainly synthesized under small momentum transfer by bombarding ions, which are not reconciled with the macro compressive stress model for the c-BN formation.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.181-181
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• 2016

Hydrogenated microcrystalline silicon (${\mu}c-Si:H$) films have attracted much attention as materials of the bottom-cells in Si thin film tandem photovoltaics due to their low bandgap and excellent stability against light soaking. However, in PECVD, the source gas $SiH_4$ must be highly diluted by $H_2$, which eventually results in low deposition rate. Moreover, it is known that high-rate ${\mu}c-Si:H$ growth is usually accompanied by a large number of dangling-bond (DB) defects in the resulting films, which act as recombination centers for photoexcited carriers, leading to a deterioration in the device performance. During film deposition, Si nanoparticles generated in $SiH_4$ discharges can be incorporated into films, and such incorporation may have effects on film properties depending on the size, structure, and volume fraction of nanoparticles incorporated into films. Here we report experimental results on the effects of nonoparticles incorporation at the different substrate temperature studied using a multi-hollow discharge plasma CVD method in which such incorporation can be significantly suppressed in upstream region by setting the gas flow velocity high enough to drive nanoparticles toward the downstream region. All experiments were performed with the multi-hollow discharge plasma CVD reactor at RT, 100, and $250^{\circ}C$, respectively. The gas flow rate ratio of $SiH_4$ to $H_2$ was 0.997. The total gas pressure P was kept at 2 Torr. The discharge frequency and power were 60 MHz, 180 W, respectively. Crystallinity Xc of resulting films was evaluated using Raman spectra. The defect densities of the films were measured with electron spin resonance (ESR). The defect density of fims deposited in the downstream region (with nonoparticles) is higher defect density than that in the upstream region (without nanoparticles) at low substrate temperature of RT and $100^{\circ}C$. This result indicates that nanoparticle incorporation can change considerably their film properties depending on the substrate temperature.