• Korean Journal of Materials Research
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• v.10 no.8
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• pp.575-580
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• 2000

Diamond thin films were deposited on $Si_3N_4$, SiC, TiC and $Al_2O_3$, substrates by the CVD method using Ta(TaC)Filament, and the appearance of the diamond films and their adhesion properties were examined by SEM, optical microscopy, indentation test and compression topple test. Diamond films were deposited at lower $CH_4$ concentration than 5%$CH_4$ for all kinds of the substrate material, but graphitic(amorphous)carbon was observed at 10%$CH_4$. The diamond film of about $12\mu\textrm{m}$ thickness on WC substrate partly peeled off, but the film on $Si_3N_4$ substrate held good adhesion. The indentation test showed that roughly ground surface was very effective for adhesion of diamond films to substrate. The topple test revealed that film thickness was an important factor governing the adhesion of the diamond film.

• Transactions on Electrical and Electronic Materials
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• v.3 no.1
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• pp.14-17
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• 2002

The effects of substrate temperatures and annealing temperatures on the microstructures and ferroelectric properties of PbZ $r_{0.52}$ $Ti_{0.48}$ $O_3$(PZT) thin fims prepared by pulsed laser deposition (PLD) were investigated. For this purpose, the PZT films were deposited at various substrate temperatures (400~$600^{\circ}C$) with post annealing process in oxygen atmosphere. The single perovskite phase was formed at the deposition temperature of 500 to 55$0^{\circ}C$ without post annealing and the PZT films deposited below 50$0^{\circ}C$ formed the single phase with post annealing at $650^{\circ}C$. The grain size of the films increased and the grain boundary of the films was clearly defined as the substrate temperature increased from 400 to 55$0^{\circ}C$. The remnant polarization (Pr) and the coercive field (Ec) of the films deposited at 55$0^{\circ}C$ and annealed at $650^{\circ}C$ were 34.3 $\mu$C/c $m^2$and 60.2 kV/cm, respectively.y.y.

• Journal of Sensor Science and Technology
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• v.6 no.1
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• pp.63-71
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• 1997

The thin-film eletroluminescent (TFEL) device having the stacked structure of ZnS:Mn/$ZnS:TbF_{3}$ has been fabricated. Insulate layers used (Pb,La)$TiO_{3}$ and $SiO_{2}$ thin films. The emission color was white. The TFEL device employing ZnS:Mn/$ZnS:TbF_{3}(8000{\AA})$ stacked phosphor layers showed the threshold voltage of $78V_{rms}$. And the brightness of the TFEL device was $400{\mu}W/cm^{2}$ at the applied voltage of $100V_{rms}$. The emission spectrum of TFEL device had a wavelength from 450nm to 620nm. The manufactured devices can be a practical use as a TFEL devices of red, green and blue by using the color filters.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.3
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• pp.70-81
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• 1998

Fiber-Fabry-Perot (FFP) tunable filters, the essential component of WDM transmission, were designed, fabricated and characterized. Multi-layered thin film mirrors that consists of an optical collimater's corss section as a substrate and TiO$_{2}$SiO$_{2}$ alternating multi-layered films as a filter wer designed by means of the transfer matrix method. Fabricated mirrors showed the high reflectivity over around 98% as expected. After fabricating the tuneable filters using PZT, we measured FSR, FWHM, finesse , crosstalk and insertion loss, confirming that the built devices satisfied the optical filter's specifications required in the SEDM transmission systems.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.393-394
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• 2005

SBN25 박막을 씨앗층으로 사용하여 이온빔으로 증착한 SBN60/SBN25 다층박막에 대하여 결정화 및 배향 특성을 고찰하였다. 기판은 Pt(111)/TiO2/SiO2/Si(100) 웨이퍼 (Pt 두께 200nm)를 사용하였으며, 약 3000${\AA}$으로 증착한후 650~$750^{\circ}C$에서 후열처리를 하였다. 제작된 박막의 증착조건 및 열처리 조건에 따른 결정화특성 변화에 대하여 연구하였으며, SBN 박막을 MFM 구조의 박막커패시터로 제조하여 강유전특성을 측정하였다.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.6.2-6.2
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• 2008

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.44-44
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• 2009

Recently, transparent ZnO-based TFTs have attracted much attention for flexible displays because they can be fabricated on plastic substrates at low temperature. We report the fabrication and characteristics of ZnO channel layers(ZnO TFTs) having different channel thicknesses. The ZnO film were deposited as active channel layers on $Si_3N_4/Ti/SiO_2p$-Si substrates by rf magnetron sputtering at $100\;^{\circ}C$ without additional annealing. Also the Zno thin films deposited at oxygen partial pressures of 40%. ZnO TFTs using a bottom-gate configuration were investigated. The $Si_3N_4$ film were deposited as gate insulator by PE-CVD at $15\;^{\circ}C$. All Processes were processed below $150^{\circ}C$ which is optimal temperature for flexible display and were used dry etching method.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.125-125
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• 2003

PZT(Pb(Zr,Ti)O3)는 우수한 강유전 특성을 가지기 때문에 FRAM (Ferroelectric Random Access Memory) 소자에 응용하기 위해 많은 연구가 진행되고 있다. 스퍼터에 의해 증착된 PZT는 처음에 pyrochlore상으로 존재하다가 후 열처리를 통해 이력 특성을 나타내는 perovskite상으로 천이된다. 일반적인 furnace열처리 방법은 고온에서의 장시간 열처리가 요구되고 Pb-loss현상이나 TiO2와 같은 이차상의 생성 그리고 하부 Pt전극의 roughness증가 및 crack과 같은 문제점이 있다. 최근 들어 후 열처리를 RTA로 이용하는 연구가 진행되고 있는데 이는 열처리 시간이 짧기 때문에 위와 같은 문제점을 개선할 수 있었다. 하지만 RTA방법 또한 어느 정도의 thermal budget이 존재하고 추가적 장비가 필요하며 기판의 전체적 가열공정이므로 다른 CMOS공정과 compatibility가 떨어진다. 따라서 본 실험에서는 위와 같은 문제를 해결하고자 노력을 집중하였고 이를 위한 새로운 열처리 방법을 개발하였다. 즉 Pt 하부전극에 전압(전류)을 인가하여 순간적으로 고온으로 결정화시키는 새로운 공정을 모색하였는데 이와 같은 방법은 열처리를 위한 추가적인 장비가 필요없고 국부적으로 순간적인 가열이기 때문에 glass기판에도 적합하며 RTA보다 승온시간 및 열처리 시간이 짧기 때문에 thermal budget도 줄일 수 있었다.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.762-769
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• 2015

The titania ($TiO_2$) nanoparticles with a diameter 2?3 nm were synthesized by controlling hydrolysis of titanium tetraisopropoxide (TTIP) in acid solution. Organic-inorganic hybrid coating solutions were prepared by reacting the titania nanoparticles with 3-glycidoxypropyl trimethoxysilane (GPTMS) by the sol-gel method. The hard coating films with high refractive index were obtained by curing thermally at $120^{\circ}C$ after spin-coating the coating solutions on the polycarbonate (PC) sheets. The coating films showed high optical transparency of 90% in the visible range and exhibited a pencil hardness of 2H. Also, the refractive index at 633 nm wavelength of coating films enhanced from 1.502 to 1.584 as the weight content of titania nanoparticles in the coating solutions increased from 4% to 25%.

• Journal of Sensor Science and Technology
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• v.6 no.4
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• pp.265-273
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• 1997

The TMA gas sensors are fabricated with the ZnO-based thin films grown by a RF magnetron sputtering method. We investigate the surface carrier concentration, Hall electron mobility, electrical resistivity and sensitivity according to temperature variation and TMA gas concentration. The ZnO-based thin film sensors prepared by sputtering in oxygen showed higher surface carrier concentration, higher Hall mobility, higher sensitivity, and lower electrical resistivity than sensors prepared by sputtering in argon. The doping ZnO-based thin film sensors showed the same electrical properties in comparison with nondoping sensors. In case of sputtering on the oxygen gaseous atmosphere, the ZnO-based thin film sensors doped with 4.0 wt.% $Al_{2}O_{3}$, 1.0 wt.% $TiO_{2}$, and 0.2 wt.% $V_{2}O_{3}$ showed the highest surface carrier concentration of $5.95{\times}10^{20}cm^{-3}$, Hall electron mobility of $177\;cm^{2}/V{\cdot}s$, lowest electrical resistivity of $0.59{\times}10^{-4}{\Omega}{\cdot}cm$ and highest sensitivity of 12.1(working temperature, $300^{\circ}C$, TMA gas, 8 ppm).