• Journal of the Korean Ceramic Society
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• v.42 no.9 s.280
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• pp.624-630
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• 2005

To investigate the possibility of the $ZrO_2$ buffer layer as the insulator for the Metal-Ferroelectric-Insulator-semiconductor (MFIS) structure, $ZrO_2$ and $SrBi_2Ta_2O_9$ (SBT) thin films were deposited on the P-type Si(111) wafer by the R.F. magnetron-sputtering method. According to the process with and without the post-annealing of the $ZrO_2$ buffer layer and SBT thin film, the diffusion amount of Sr, Bi, Ta elements show slight difference through the Glow Discharge Spectrometer (GDS) analysis. From X-ray Photoelectron Spectroscopy (XPS) results, we could confirm that the post-annealing process affects the chemical binding condition of the interface between the $ZrO_2$ thin film and the Si substrate. Compared to the MFIS structure without the post-annealing of the $ZrO_2$ buffer layer, memory window value of MFlS structure with post-annealing of the $ZrO_2$ buffer layer were considerably improved. The window memory of the Pt/SBT (260 nm, $800^{\circ}C)/ZrO_2$ (20 nm) structure increases from 0.75 to 2.2 V under the applied voltage of 9 V after post-annealing.

• Journal of the Korean Ceramic Society
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• v.34 no.1
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• pp.88-94
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• 1997

The oxidation behavior of the NiCrAlY bond coat and thermal fatigue failure in the plasma-sprayed thermal barrier coating system, ZrO2.8wt%Y2O3 top coat/Ni-26Cr-5Al-0.5Y bond coat/Hastelloy X superalloy substrate, in commercial use for finned segment of gas turbine burner were investigated. The main oxides formed in the bond coat were NiO, Cr2O3, and Al2O3. It divided the oxide distribution at this interface into two types whether an Al2O3 thin layer existed beneath ZrO2/bond coat interface before operation at high temperature or not. While a continuous layer of NiO was formed mainly in the region where the Al2O3 thin layer was present, the absence of it resulted in the formation of mixture of Cr2O3 and Al2O3 beneath NiO layer. Analyses on the fracture surface of specimen spalled by thermal cycling showed that spalling occurred mainly along the ceram-ic coat near ZrO2/bond coat oxide layer interface, but slightly in the oxide layer region.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.3
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• pp.139-143
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• 2017

N-type crystalline silicon solar cells have high metal impurity tolerance and higher minority carrier lifetime that increases conversion efficiency. However, junction quality between the boron diffused layer and the n-type substrate is more important for increased efficiency. In this paper, the current status and prospects for boron diffused layers in N-type crystalline silicon solar cell applications are described. Boron diffused layer formation methods (thermal diffusion and co-diffusion using $a-SiO_X:B$), boron rich layer (BRL) and boron silicate glass (BSG) reactions, and analysis of the effects to improve junction characteristics are discussed. In-situ oxidation is performed to remove the boron rich layer. The oxidation process after diffusion shows a lower B-O peak than before the Oxidation process was changed into $SiO_2$ phase by FTIR and BRL. The $a-SiO_X:B$ layer is deposited by PECVD using $SiH_4$, $B_2H_6$, $H_2$, $CO_2$ gases in N-type wafer and annealed by thermal tube furnace for performing the P+ layer. MCLT (minority carrier lifetime) is improved by increasing $SiH_4$ and $B_2H_6$. When $a-SiO_X:B$ is removed, the Si-O peak decreases and the B-H peak declines a little, but MCLT is improved by hydrogen passivated inactive boron atoms. In this paper, we focused on the boron emitter for N-type crystalline solar cells.

• Electrical & Electronic Materials
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• v.9 no.5
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• pp.463-469
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• 1996

The double insulating layer consisting of anodic oxide and ZnS was formed for HgCdTe metal insulator semiconductor(MIS) structure. ZnS was evaporated on the anodic oxide grown in H$_{2}$O$_{2}$ electrolyte. Recently, this insulating mechanism for HgCdTe MIS has been deeply studied for improving HgCdTe surface passivation. It was found through TEM observation that an interface layer is formed between ZnS and anodic oxide layers for the first time in the study of this area. EDS analysis of chemical compositions using by electron beam of 20.angs. in diameter and XPS depth composition profile indicated strongly that the new interface is composed of ZnO. Also TEM high resolution image showed that the structure of oxide layer has been changed from the amorphous state to the microsrystalline structure of 100.angs. in diameter after the evaporation of ZnS. The double insulating layer with the resistivity of 10$^{10}$ .ohm.cm was estimated to be proper insulating layer of HgCdTe MIS device. The optical reflectance of about 7% in the region of 5.mu.m showed anti-reflection effect of the insulating layer. The measured C-V curve showed the large shoft of flat band voltage due to the high density of fixed oxide charges about 1.2*10$^{12}$ /cm$^{2}$. The oxygen vacancies and possible cationic state of Zn in the anodic oxide layer are estimated to cause this high density of fixed oxide charges.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.4
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• pp.353-361
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• 2001

A new stereoscopic codec. structure using MPEG-2 multiview profile is presented in this paper. In the suggested codec., the left image is coded with motion estimation in the base layer and the right image is coded with disparity estimation in the enhancement layer. Since it is possible to calculate rough motion of the right image sequence with disparity and motion of the left image sequence, motion compensation of the enhancement layer is performed without motion estimation. To apply this mathod to MVP codec., the prediction mode of base layer and enhancement layer is restricted, and B picture mode in the base layer is removed. Since the proposed codec. does not perform motion estimation in the enhancement layer encoding and prediction mode of base layer is restricted, it's structure is simple and reduces the encoding time. We compared the SNR of encoded image with three different structured codec., and the experimental results show suggested codec. have comparable result.

• Current Photovoltaic Research
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• v.1 no.2
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• pp.103-108
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• 2013

Epitaxial growth of a high-quality thin Si film is essential for the application to low-cost thin-film Si solar cells. A polycrystalline Si film was grown on a $SiO_2$ substrate at $450^{\circ}C$ by a Al-assisted crystal growth process. For the purpose, a thin Al layer was deposited on the $SiO_2$ substrate for Al-assisted crystal growth. However, the epitaxial growth of Si film resulted in a rough surface with humps. Then, we introduced a thin amorphous Si seed layer on the Al film to minimize the initial roughness of Si film. With the help of the Si seed layer, the surface of the epitaxial Si film was smooth and the crystallinity of the Si film was much improved. The grain size of the $1.5-{\mu}m$-thick Si film was as large as 1 mm. The Al content in the Si film was 3.7% and the hole concentration was estimated to be $3{\times}10^{17}/cm^3$, which was one order of magnitude higher than desirable value for Si base layer. The results suggest that Al-doped Si layer could be use as a seed layer for additional epitaxial growth of intrinsic or boron-doped Si layer because the Al-doped Si layer has large grains.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.396-396
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• 2013

The resistive random access memory (ReRAM) has several advantages to apply next generation non-volatile memory device, because of fast switching time, long retentions, and large memory windows. The high mobility of monolayered graphene showed several possibilities for scale down and electrical property enhancement of memory device. In this study, the monolayered graphene grown by chemical vapor deposition was transferred to $SiO_2$ (100 nm)/Si substrate and glass by using PMMA coating method. For formation of metal-oxide nanoparticles, we used a chemical reaction between metal films and polyamic acid layer. The 50-nm thick BPDA-PDA polyamic acid layer was coated on the graphene layer. Through soft baking at $125^{\circ}C$ or 30 min, solvent in polyimide layer was removed. Then, 5-nm-thick indium layer was deposited by using thermal evaporator at room temperature. And then, the second polyimide layer was coated on the indium thin film. After remove solvent and open bottom graphene layer, the samples were annealed at $400^{\circ}C$ or 1 hr by using furnace in $N_2$ ambient. The average diameter and density of nanoparticle were depending on annealing temperature and times. During annealing process, the metal and oxygen ions combined to create $In_2O_3$ nanoparticle in the polyimide layer. The electrical properties of $In_2O_3$ nanoparticle ReRAM such as current-voltage curve, operation speed and retention discussed for applictions of transparent and flexible hybrid ReRAM device.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.10
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• pp.859-864
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• 2000

Recently IR detecting devices using MEMS have been actively studied. Microbolometer, one of these devices, detects the change of resistivity as the change of temperature of the device by absorbing IR, IR absorbing materials for microbolometer should have high TCR value and low noise characteristics which depends on resistivity. We fabricated multi-layer VOx thin films to improve the IR detectivity of uncooled IR devices and analyzed IR absorbing characteristics. We fabricated multi-layer VOx thin films by RF reactive sputtering method on SiNx substrate and changed characteristics using the different thickness of V and V$_2$O$\_$5/ thin films. Then we annealed them under 300$\^{C}$. The TCR (Temperature Coefficient of Resistance) measurement was carried out to estimate the IR detectivity of multi-layer VOx thin films. XRD (X-Ray Diffraction) analysis was carried out to estimate the IR detectivity of multi-layer VOx thin films. ZXRD (X-Ray Diffraction) analysis was used to find out phases and structures of V and V$_2$O$\_$5/ thin films. AES (Auger Electron Spectroscopy) analysis was used to find out composition of multi-layer VOx thin films before and after annealing. We obtained the optimum thickness range of V and V$_2$O$\_$5/ thin films from the result of AES analysis. We changed the thickness of V$_2$O$\_$5/ about 20 to 150 $\AA$ and thickness of V about 10 to 20 $\AA$. As the result of this, TCR value of multi-layer VOx thin films was about -2%/k and the resistivity was ∼1Ωcm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.04a
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• pp.56-57
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• 2006

In this paper, the inorganic multi-layer thin film encapsulation was newly adopted to protect the organic layer from moisture and oxygen. Using the electron beam, Sputter, inorganic multi-layer thin-film encapsulation was deposited onto the Ethylene Terephthalate(PET) and their interface properties between inorganic and organic layer were investigated. In this investigation, the SiON SiO2 and parylene layer showed the most suitable properties. Under these conditions, the WVTR for PET can be reduced from a level of $0.57\;g/m^2/day$ (bare subtrate) to 1*10-5 g/$m^2$/day after application of a SiON and SiO2 layer. These results indicates that the PET/SiO2/SiON/Parylene barrier coatings have high potential for flexible organic light-emitting diode(OLED) applications.

• International Journal of Industrial Entomology and Biomaterials
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• v.35 no.2
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• pp.71-76
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• 2017

The cocoon's color of silkworm, Bombyx mori L. is usually white. But some are yellow, flesh and green colors because of modified characteristics. The yellow and flesh cocoons depend on carotenoid pigments, green cocoons are determined by flavonoid pigments. The cocoon's color is affected by the genes controlling penetration process from midgut to coelom and silk gland. Y (Yellow blood, 2-25.6) and I (Yellow-inhibitor, 9-16.2) genes are involved in the penetration process of carotenoid pigments from midgut to coelom, C (Outer-layer yellow cocoon, 12-7.2) and F (Flesh, 6-13.6) genes from coelom to silk gland. Therefore, the carotenoid cocoon's color depends on the genotype Y, I, C and F genes and their combination. Among them, C gene is sympathetic gene, which are known as C, CI and CD. C (Outer-layer yellow cocoon) genes make yellow cocoons on outer-layer and white cocoons on inter-layer, and CI (Inner-layer yellow cocoon) genes do yellow cocoons on inter-layer and dilute yellow cocoons on outer-layer. CD gene is known as making dilute yellow cocoons all layer. In this study, we have checked the dominance relation of C sympathetic genes among carotenoid genes for color cocoons by using strains related to the genes for color cocoons and investigated the aspect that pigments were penetrated in silk gland by action of each gene.