• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.965-968
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• 2007

In this study we investigated the variation of the substrate temperatures using RF sputtering to identify the effect on the structure and electrical properties by c-axis orientation of ZnO thin film. ZnO thin films were prepared on Al/Si substrate. In our experimental results, ZnO thin film at $300^{\circ}C$ was well grown with (002) peak of ZnO thin film, the thin film showed the high resistivity with the value of $5.9{\times}10^7\;{\Omega}cm$ and the roughness with 27.06 nm. As increased the substrate temperatures, the grain size of ZnO thin films was increased. From these results, we could confirm the suitable substrate temperature of ZnO thin films for FBAR(film bulk acoustic resonator).

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1879-1881
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• 1999

(Ba,Sr)$TiO_3$[BST] thin films were fabricated on Pt/Ti/$SiO_2$/Si substrate by RF sputtering. We investigated the effects of substrate temperature on the structural and dielectric properties of BST thin films. Increasing the substrate temperature, barium multi titanate phases were decreased, and BST (100), (200) peaks were increased. The relative dielectric constant and dielectric loss of the BST thin films at the substrate temperature of $500^{\circ}C$ were 300 and 0.018, respectively at l[kHz]. In all films, the dielectric constants decreased. Dielectric losses increased as increasing the frequency. The switching voltage was 5V of the BST thin films at the substrate temperature of $500^{\circ}C$.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.7
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• pp.974-979
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• 2013

$TiO_2$ thin films are fabricated using R.F.sputtering method. $TiO_2$ thin films are coated on $Al_2O_3$ substrate printed IDE(interdigitated electrode). Impedance of thin films decreases according to increase relative humidity and it increases according to decrease measuring frequency. When substrate temperature is room temperature, impedance of thin films is from 45.68[MHz] to 37.76[MHz] within the limits from 30[%RH] to 75[%RH] at 1[kHz]. Whereas when substrate temperature is 100[$^{\circ}C$], impedance of thin films is from 692[kHz] to 539[kHz] within the limits from 30[%RH] to 75[%RH] at 1[kHz]. Impedance variation of thin films is bigger in low frequency regions than in high frequency regions. When substrate temperature is 100[$^{\circ}C$], impedance of thin films is lower than that of room temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.901-904
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• 2001

For the c-axis oriented epitaxial YBa$_2$Cu$_3$O$_{7-{\delta}}$ thin film on r-cut sapphire substrate it is necessary to deposit buffer layers. The CeO$_2$buffer layer was deposited on sapphire substrate using RF magnetron sputtering system. We investigated XRD pattern of CeO$_2$thin films at various sputtering conditions such as sputtering gas ratio, sputtering power, target to substrate distance, sputtering pressure and substrate temperature. The optimum condition was 15 mTorr with deposition pressure, 1:1.2 with $O_2$and Ar ratio and 9cm with target to substrate distance. The CeO$_2$(200) peak was notable for a deposition temperature above 75$0^{\circ}C$. The YBa$_2$Cu$_3$O$_{7-{\delta}}$ was deposited on CeO$_2$buffered r-cut sapphire substrate using pulsed laser ablation. The YBa$_2$Cu$_3$O$_{7-{\delta}}$CeO$_2$(200)/A1$_2$O$_3$thin film was exhibited a critical temperature of 89K.xhibited a critical temperature of 89K.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1279_1280
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• 2009

Vanadium dioxide(VO2) has been reported to be the most attractive material for thermochromic windows due to its semiconductor-metal phase transition at around $68^{\circ}C$. However, our previous experiment showed it is difficult to grow VO2 thin films directly on glass substrate, whereas thermochromic VO2 thin films were successfully grown on R-cut sapphire substrate. Properties of VO2 thin films on different orientations of sapphire substrates were already reported. Furthermore, VO2 thin films were successfully grown heteroepitaxially on (001) preferred oriented ZnO coated glass. We deposited VO2 thin films using V2O5 targets on substrates with various lattice parameters with same orientation(SrTiO3, MgO, and Sapphire substrate of (001) orientation) by pulsed laser deposition. In this work, we will discuss the effects of lattice misfit, substrate-induced stress and grain size on the properties of VO2 thin films deposited on various substrate materials.

• Journal of the Semiconductor & Display Technology
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• v.19 no.3
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• pp.100-105
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• 2020

Recently, as display and semiconductor devices have been miniaturized and highly integrated, there is a demand for optimization of the structural characteristics of the thin film accordingly. The sputtering device has the advantage of stably obtaining a desired thin film depending on the material selected for the target. However, due to the structural characteristics of the sputtering equipment, the structural characteristics of the film may be different depending on the incidence angle of the sputtering target material to the substrate. In this study, the characteristics of the thin film material according to the scattering angle of the target material and the incidence position of the substrate were studied to find the optimization design rule of the sputtering equipment. To this end, a Si thin film of 1 ㎛ or less was deposited on the Si(100) substrate, and then the microstructure, reflectance, surface roughness, and thin film crystallinity of the thin film formed for each substrate location were investigated. As a result of the study, it was found that as the sputter scattering angle increased and the substrate incident angle decreased, the gap energy along with the surface structure of the thin film increased from 1.47 eV to 1.63 eV, gradually changing to a non-conductive tendency.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.1
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• pp.34-42
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• 2001

The influences of substrate temperature were studied when fabricating KLN thin film on amorphous substrate using an rf-magnetron sputtering method. Investigating the vaporization temperature of the each element, the excess ratio of target and the optimum deposition conditions were effectively selected when thin filmizing a material which have elements with large difference fo vaporization temperature. In order to compensate K and Li which have lower vaporization temperatures than Nb, KLN target of composition excess with K of 60% and Li of 30% was used. KLN thin film fabricated on Corning 1737 glass substrate had single KLN phase above 58$0^{\circ}C$ of substrate temperature and crystallized to c-axis direction. The optimum conditions were rf power of 100W, process pressure of 150mTorr, and substrate temperature of $600^{\circ}C$.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.52.1-52.1
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• 2009

Cupric oxide (CuO) is a p-type semiconductor with band gap of ~1.7 eV and reported to be suitable for catalysis, lithium-copper oxide electrochemical cells, and gas sensors applications. The nanoparticles, plates and nanowires of CuO were found sensing to NO2, H2S and CO. In this work, we report about the comparison about hydrogen sensing of nano thin film and nanowires structured CuO deposited on single-walled carbon nanotubes (SWNTs). The thin film and nanowires are synthesized by deposition of Cu on different substrate followed by oxidation process. Nano thin films of CuO are deposited on thermally oxidized silicon substrate, whereas nanowires are synthesized by using a porous thin film of SWNTs as substrate. The hydrogen sensing properties of synthesized materials are investigated. The results showed that nanowires cupric oxide deposited on SWNTs showed higher sensitivity to hydrogen than those of nano thin film CuO did.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.04a
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• pp.81-83
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• 2003

We have investigated the generation of pretilt angle for a nematic liquid crystal (NLC) alignment with rubbing alignment method on polyimide surfaces using thin plastic substrates. It was found that monodomain alignment of LNC is obtained with rubbing alignment method on polyimide surfaces using thin plastic substrates. The generated NLC pretilt angles are about $3^{\circ}$ by the rubbing alignment method on thin plastic substrates, However, the pretilt angle measured at about $1.7^{\circ}$ lower on the glass substrate than by thin plastic substrate. It is considered that this alignment may be attributed to roughness of micro groove substrate. The tilt angle increases with increasing baking temperature for making polyimide layer using glass substrate. It was concluded that pretilt angle in the polyimide surface is attributable to the increasing of imide rato.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.200-202
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• 2004

ZnO thin films were grown at different plume-substrate angles by pulsed laser deposition(PLD). From the X-ray diffraction(XRD) result, all ZnO thin films were found to be well c-axis oriented and c-axis lattice constant approached the value of bulk ZnO as plume-substrate(P-S) angle decreased. The grain size of ZnO thin films measured by atomic force microscopy increased and the UV intensity of ZnO thin films investigated by photoluminescence increased as P-S angle decreased. It is found that the improvement of structural and optical properties mainly comes from the reduction of the flux of ablated species arriving on a substrate per a laser shot by tilting a substrate parallel to the plume propagation direction.