• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.181-185
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• 2007

We report on our material and process research on ZnO:Al films and on our investigations on wet chemical etching using a variety of etching solutions. We achieve resistivity as low as $750{\mu}{\Omega}cm$ for ZnO:Al films with film thickness of 140 nm. Etching with phosphorous acid allows for accurate fine patterning of the ZnO:Al films on glass substrates.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.5
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• pp.379-384
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• 1999

Langmuir-Blodgett(LB) films which have high ordered orientation and ordering structure are fabricated by LB method which deposit the ultra-thin films of organic materials at a molecular level. The electrical characteristics of stearic acid LB ultra-thin films for the horizontal direction were investigated to develop the gas sensor using LB ultra-thin films. The optimal deposition condition to deposit the LB ultra-thin films was obtained from $\pi-A$ isotherms and the deposition status of stearic acid LB ultra-thin films was verified by the measurement of deposition ratio, UV-absorbance, and electrical properties for LB ultra-thin films. The conductivity of stearic acid LB ultra-thin films for horizontal direction was about $10_{-8}[S/cm]$. The activation energy for LB ultra-thin films with respect to variation of temperature was about 1.0[eV], which was correspond to semiconductor material. The response characteristics for organic gas were confirmed by measuring the response time, recovery time, and reproducibility of the LB ultra-thin to each organic gas. Also, the penetration and adsorption behavior of gas molecule were confirmed through the organic gas response characteristics of LB ultra-thin films with respect to temperature.

• Journal of the Korean Ceramic Society
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• v.43 no.11 s.294
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• pp.715-723
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• 2006

Perovskite oxide materials are very important for the electronics industry, because they exhibit promising properties. With an interest in the obvious applications, significant effort has been invested in the growth of highly crystalline epitaxial perovskite oxide thin films in our laboratory. And the desired structure of films was formed to achieve excellent properties. $Y_1Ba_2Cu_3O_{7-x}$ (YBCO) superconducting thin films were simultaneously deposited on both sides of 3 inch wafer by inverted cylindrical sputtering. Values of microwave surface resistance R$_2$ (75 K, 145 GHz, 0 T) smaller than 100 m$\Omega$ were reached over the whole area of YBCO thin films by pre-seeded a self-template layer. For implementation of voltage tunable high-quality varactor, A tri-layer structured SrTiO$_3$ (STO) thin films with different tetragonal distortion degree was prepared in order to simultaneously achieve a large relative capacitance change and a small dielectric loss. Highly a-axis textured $Ba_{0.65}Sr_{0.35}TiO_3$ (BST65/35) thin films was grown on Pt/Ti/SiO$_2$/Si substrate for monolithic bolometers by introducing $Ba_{0.65}Sr_{0.35}RuO_3$ (BSR65/35) thin films as buffer layer. With the buffer layer, the leakage current density of BST65/35 thin films were greatly reduced, and the pyroelectric coefficient of $7.6\times10_{-7}$ C $cm^{-2}$ $K^{-1}$ was achieved at 6 V/$\mu$m bias and room temperature.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.2
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• pp.77-81
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• 2002

In this study, PZT thin films were fabricated using sol-gel processing onto Si/$SiO_2$/Ti/Pt substrates. PZT sol with different Zr/Ti ratio(20/80, 30/70, 40/60, 52/48) were prepared, respectively. The films were fabricated by using the spin-coating method on substrates. The films were heat treated at $450^{\circ}C$, $650^{\circ}C$ by rapid thermal annealing(RTA). The preferred orientation of the PZT thin films were observed by X-ray diffraction(XRD), and Scanning electron microscopy(SEM). All of the resulting PZT thin films were crystallized with perovskite phase. The fine crystallinity of the films were fabricated. Also, we found that the ferroelectric properties from the dielectric constant of the PZT thin films were over 600 degrees, P-E hysteresis constant. And the leakage current densities of films were lower than $10^{-8}A/cm^2$. It is concluded that the PZT thin films by sol-gel process to be convinced of application for ferroelectric memory device.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.151-152
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• 2009

We coated $TiO_2$ thin films on particles by a rotating cylindrical plasma chemical vapor deposition (PCVD) process and investigated the effects of various process variables on the morphology and growth of thin films. The polypropylene (PP) particles were rotated with the cylindrical PCVD reactor and they were coated with $TiO_2$ thin films uniformly by the deposition of thin mm precursors in the gas phase. The $TiO_2$ thin films were coated on the PP particles uniformly and the thickness of thin films almost proportional to the deposition time. The $TiO_2$ thin films grew more quickly on the PP particles with increasing rotation speed of the reactor. This study shows that a rotating cylindrical PCVD reactor can be a good method to coat high-quality $TiO_2$ thin films uniformly on particles.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.54.2-54.2
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• 2012

Solid-state dewetting of thin films is a process through which continuous solid films decay to form islands. Dewetting of thin films has long been a critical issue in microelectronics and much effort has been made to prevent the process and enhance the stability of films. On the other hand, dewetting has also been purposely induced to create arrays of particles and other structures for applications, including plasmonic structures and catalysts for growing nanotube and nanowire. We have investigated ways of producing regular structures via templated dewetting of thin films. Mainly, two different approaches have been used in our works to template dewetting of thin films: periodic topographical templating and planar patterning of epitaxially-grown films. Dewetting of topographically-patterned thin films results in the formation of nanoparticle arrays with spatial and crystallographic orders. Morphological evolution during templated-dewetting of single crystal films occurs in deterministic ways because of geometric and crystallographic constraints, and leads to the formation of regular structures with smaller sizes and more complex shapes than the initial patches. These results will be reviewed in this presentation.

• 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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• 1993.11a
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• pp.120-123
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• 1993

This paper describes the deposition and characteristics of electrochromic tungsten oxide thin films for electrochromic smart windows. Tungsten Oxide thin films(WO$_3$) are deposited by thermal evaporation techniques. By varying deposition parameters, WO$_3$ thin films exhibit different optical properties. The electrochromic devices are consist of ITO glass/ WO$_3$ thin films/ LiClO$_4$-propylene carbonate electrolyte/ counter electrode. The electrochromic properties of tungsten oxide thin films with different deposition condition ale investigated.

• Proceedings of the Korean Vacuum Society Conference
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• 2004.08a
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• pp.245-245
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• 2004

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.1
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• pp.13-17
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• 2005

The Pb(Zr/sub 0.52/Ti/sub 0.48/)O₃/(Ba/sub 0.6/Sr/sub 0.4/)TiO₃[PZT/BST] heterolayered thin films were deposited on Pt/Ti/SiO₂/Si substrates by using the RF sputtering method with different RF power. The PZT/BST heterolayered thin films had the tetragonal structure of the PZT phase and BST phase. Increasing the RF power. the intensity of the PZT (100), (110) peaks and BST (111) peaks were decreased and the intensity of the BST (100), (110) peaks were increased. The thickness ratio of the top layered BST thin film and the bottom layered PZT thin film was 2 to1. The atomic concentration of the Ba, Sr, Pb. Zr, Ti atoms were constant in the PZT thin films and BST thin films, respectively. The Pt atom was diffused to the PZT region in the PZT/BST heterolayered thin films deposited at condition of 60[W] RF power. Increasing the frequency, dielectric constant and loss of the PZT/BST heterolayered thin films were decreased. The dielectric constant and loss of the PZT/BST heterolayered thin films deposited with RF power of 90[W] were 406 and 3%, respectively.