• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.316-319
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• 2000

By RF magnetron sputtering ZnGa$_2$O$_4$thin films were prepared on Si(100) wafer in terms of RF power, substrate temperatures and Ar/O$_2$flow rate. Crystallographic orientation was characterized by x-ray diffraction(XRD). Surface morphology and microstructure were observed by scanning electron microscope(SEM). Photoluminescence(PL) measurement was employed to observe the emission spectra of ZnGa$_2$O$_4$films. The influences of various deposition parameters on the properties of grown films were studied. PL spectrum of ZnGa$_2$O$_4$thin films showed broad band luminescence spectrum.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.3
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• pp.177-182
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• 2010

The pentacene-based organic thin film transistors(OTFTs) using polyvinylalcohol(PVA) alignment layer were fabricated on the $SiO_2$ evaporated to n-type (111) Si substrates. The pentacene film was deposited by thermally evaporated at $10^{-7}$ torr. X-ray diffraction (XRD) and atomic force microscope(AFM) measurement showed pentacene film which deposited on rubbed PVA layers were partially crystallized at (001) plane. The pentacene OTFTs with PVA layers rubbed perpendicular to the direction of current flow was shown to align better orientation than parallel rubbed case and thus to enhance the mobility and saturation current by a factor of 2.3 respectively. We obtained mobility by 0.026 $cm^2$/Vs and on-off current ratio by ${\sim}10^8$.

• Transactions on Electrical and Electronic Materials
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• v.16 no.1
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• pp.1-4
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• 2015

(111)-oriented and random oriented $Pb_{0.8}Ba_{0.2}ZrO_3$ (PBZ) perovskite relaxor ferroelectric thin films were fabricated on Pt(111)/$TiO_x$/$SiO_2$/Si substrate by sol-gel method. Nano-scaled antiferroelectric and ferroelectric two-phase coexisted in both (111)-oriented and random oriented PBZ thin film. High dielectric tunability (${\eta}=75%$, E = 560 kV/cm) and figure-of-merit (FOM ~ 236) at room temperature was obtained in (111)-oriented thin film. Meanwhile, giant electrocaloric effect (ECE) (${\Delta}T=45.3K$ and ${\Delta}S=46.9JK^{-1}kg^{-1}$ at $598kVcm^{-1}$) at room temperature (290 K), rather than at its Curie temperature (408 K), was observed in random oriented $Pb_{0.8}Ba_{0.2}ZrO_3$ (PBZ) thin film, which makes it a promising material for the application to cooling systems near room temperature. The giant ECE as well as high dielectric tunability are attributed to the coexistence of AFE and FE phases and field-induced nano-scaled AFE to FE phase transition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.197-197
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• 2010

Pb(Zr,Ti)O3/BiFeO3/(PZT/BFO) multilayer thin films were coated on Pt/Ti/SiO2/Si substrates by chemical solution deposition. With increasing the annealing temperature, the dielectric and leakage current density properties of multilayered PZT/BFO/PZT thin films were improved. The current density of the PZT/BFO/PZT filmannealing at $600^{\circ}C$ was about 189.39(x10-9A/cm2) at 10V. The relative dielectric constant and the dielectric loss of the PZT/BFO/PZT thin film annealing at $600^{\circ}C$ were about 318 and 0.161%, respectively.

• Journal of the Korean Vacuum Society
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• v.3 no.1
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• pp.59-64
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• 1994

극소전자 디바이스의 고집적화와 더불어 박막배선의 선폭은 0.5$\mu$m이하까지 축소되며 초고집적 submicron 박막금속화가 진행되고 있다. 미세회로에 적용되어지는 배선재료는 인가되는 고전류밀도로 인하여 electromigration 에 의한 결함이 쉽게 발생한다는 단점이있다. 금속박막 전도체위의 dielectric overlayer는 electromigration 에 대한 passivation 효과를 보여 극소전자 디바이스의 평균수명을 향상시 킨다.본 연구에서는 박막금속화에서 dielectric overlayer의 passivation 효과를 알아보기 위하여 약 3000 $\AA$ 두께의 Al,Al-1%Si, Ag 그리고 Cu 박막배선위에 증착하여 SiO2절연보호막의 유무에 따른 박막배선 의 수명변화 및 신뢰도를 측정하였다. 박막배선에 인가된 전류밀도는 1x106 A/cm2와 1x107 A/cm2 이었다. SiO2 dielectric overlayer는 Al,Al-1%Si Ag. Cu 박막배선에서는 electromigration에 대한 보호막 혀과를 보이며 평균수명을 모두 향상시킨다. SiO2 passivation 효과는 Al, Ag, Cu 박막중 Cu 박막배선에서 가 장 크게 나타났다. SiO2 dielectric overlayer가 형성되지 않은 경우 Al 박막배선의 수명이 가장 긴 것으 로 나타났으나 SiO2 가 형성된 경우는 Cu 박막배선의 수명이 가장 길게 나타났다.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.342-346
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• 2004

Recently there has been a great world-wide interest in developing and characterizing new nano-structured materials. These newly developed materials are often prepared in limited quantities and shapes unsuitable for the extensive mechanical testing. The development of depth sensing indentation methods have introduced the advantage of load and depth measurement during the indentation cycle. In the present work, ZnO thin films are prepared on the Glass, GaAs(100), Si(111), and Si(100) substrates at different temperatures by pulsed laser deposition(PLD) method. Because the potential energy in c-axis is law, the films always shaw c-axis orientation at the optimized conditions in spite of the different substrates. Thin films are investigated by X-ray diffractometer and Nano indentation equipment. From these measurements it is possible to get elastic modulus and hardness of ZnO thin films on all substrates.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.115-118
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• 2000

Uncooled pyroelectric infrared detectors based on BST(B $a_{-x}$S $r_{x}$Ti $O_3$) thin films have been fabricated by RF magnetron sputtering and surface Micromachining technology. The detectors form BST thin film ferroelectric capacitors grown by RF magnetron sputtering on N/O/N(S $i_3$ $N_4$/ $SiO_2$/S $i_3$ $N_4$) membrane. The sputtered BST thin film exhibits highly c-axis oriented crystal structure that no poling treatment for sensing applications is required. This is an essential factor to increase the yield for realization of an infrared image sensor. surface-Micromachining technology is used to lower the thermal mass of the detector by giving maximum sensor efficiency Gold-black is evaporated on top of the sensing elements used the thermal evaporator. fabricated uncooled pyroelectric infrared detectors is highly output voltage at the low temperature(1$^{\circ}C$).).).

• Journal of the Korean Society of Radiology
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• v.17 no.4
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• pp.625-631
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• 2023

The important requirement of industrial dynamic X-ray detector operating under high tube voltage up to 450 kVp for 24 hours and 7 days is to obtain significantly high radiation resistance. This study presents the radiation resistance characteristics of various thin film transistors (TFTs) with a-Si, poly-Si and IGZO semiconducting layers. IGZO TFT offering dozens of times higher field effect mobility than a-Si TFT was processed with highly hydrogenated plasma in between IGZO semiconducting layer and inter-layered dielectric. The hydrogenated IGZO TFT showed most sustainable radiation resistance up to 10,000Gy accumulated, thus, concluded that it is a sole switching device in X-ray imaging sensor offering dynamic X-ray imaging at high frame rate under extremely severe radiation environment such as automated X-ray inspection.

• Current Photovoltaic Research
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• v.11 no.2
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• pp.39-43
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• 2023

Carrier-selective contacts (CSCs) solar cells are considerably attractive on highly efficient crystalline silicon heterojunction (SHJ) solar cells due to their advantages of high thermal tolerance and the simple fabrication process. CSCs solar cells require a hole selective contact (HSC) layer that selectively collects only holes. In order to selectively collect holes, it must have a work function characteristic of 5.0 eV or more when contacted with n-type Si. The VO_x, NiO_x, and CuI_x thin films were fabricated and analyzed respectively to confirm their potential usage as a hole-selective contact (HSC) layer. All thin films showed characteristics of band-gap engergy > 3.0 eV, work function > 5.0 eV and minority carrier lifetime > 1.5 ms.

• Korean Journal of Materials Research
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• v.4 no.6
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• pp.715-722
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• 1994

Thermochromic $Vo_{2}$ thin films for "smart windows" were prepared by electron beam evaporationmethod on a glass substrate and spectral transmittances were examined by spectrophotometer. Substratetemperature of $300^{\circ}C$ and annealing temperature of $400^{\circ}C$ were found to be effective to give athermochromism on $Vo_{2}$ thin film due to the crystallization of the thin film. Furthermore, annealing of$Vo_{2}$ thin film affected the spectral transmittance and reduced the transmittance significantly at wavelengthbelow 500nm.$V_{0.95}W_{0.05}O_{2}$ thin film doped by 5 atomic percent of W showed semiconductor-metal transition around 0$0^{\circ}V_{0.995}W_{0.005}O_{2}$thin film which contains 0.5 atomic percent Sn showed therrnochrornisrn when it was depositedat substrate temperature of $300^{\circ}C$ and annealed at $450^{\circ}C$ for 5 hours in argon gas. The transitiontemperature of the $V_{0.995}W_{0.005}O_{2}$ thin film was found to be about $25^{\circ}C$ and showed some hysterisis. and showed some hysterisis.