• Journal of Sensor Science and Technology
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• v.5 no.5
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• pp.69-77
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• 1996

In this paper, we fabricated the micro hotplate which consisted of a thin film heater(Pt/Cr bilayers) sandwiched with the thermal oxide and E-beam evaporated oxide. And we studied the electrical and the structural properties of Pt/Cr bilayers due to annealing temperature. When we compared the temperature measured from type k thermocouples with the temperature acquired from I.R. thermo-vision system according to the variations of emissivity, the emissivity of I-beam evaporated oxide was 0.5. The sheet resistance of Pt/Cr bilayers didn't depend on the Cr layer thickness, and it was considered as the existence of CrO between the Pt and the Cr layer. When the annealing temperature was increased from $500^{\circ}C$ to $700^{\circ}C$, the out-diffusions of Cr were increased(which was confirmed by AES depth profile) and the grain size of Pt(220) phase was enlarged also(analyzed by XRD and SEM photographs). From the results of XRD analysis and AES depth profile, the Pt/Cr bilayers annealed at $500^{\circ}C$ were more stable than any other cases in structural properties.

• Analytical Science and Technology
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• v.19 no.5
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• pp.407-414
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• 2006

An X-ray diffractometer for spatially resolved X-ray diffraction measurements was developed to identify phase in the narrow (micron-scaled) region of high burn-up fuels and some nuclear materials. The micro-XRD was composed of an X-ray microbeam alignment system and a sample micro translation system instead of a normal slit and a fixed sample stage in a commercial XRD. The X-ray microbeam alignment system was fabricated with a microbeam concentrator having two Ni deposited mirrors, a vertical positioner, and a tilt table for the generation of a concentrated microbeam. The sample micro translation system was made with a sample holder and a horizontal translator, allowing movement of a specimen at $5{\mu}m$ steps. The angular intensity profile of the microbeam generated through a concentrator was symmetric and not distorted. The size of the microbeam was $4,000{\times}20{\mu}m$ and the spatial resolution of the beam was $47{\mu}m$ at the sample position. When the diffraction peaks were measured for a $UO_2$ pellet specimen by this system, the reproducibility ($2{\Theta}={\pm}0.01^{\circ}$) of the peaks was as good as a conventional X-ray diffractometer. For the cross section of oxidized titanium metal, not only $TiO_2$ in an outer layer but also TiO near an oxide-metal interface was observed.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.370-372
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• 1995

This paper mainly, describes the electrical characteristics caused by the change of structure in solid state of specimen by electron beam irradiation of high temperature-low expension type molding materials of power semiconductor element. The experiments on physical properties and electrical characteristics for the specimen irradiated electron beam are carried ont. For the investigation on physical properties, XRD analysis is used. And for the experiment of electrical characteristics, measurement of volumn resistivity is used.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.44.1-44.1
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• 2009

최근 경조직 재생 (hard tissue regeneration) 에 대한 연구가 활발히 진행되고 있다. 그러나 이와같은 연구는 결손도입의 어려움 및 이차적인 골절의 위험성 때문에 대형동물을 중심으로 진행되고 있으며, 그 결과 동물실험에 있어서 시간적 경제적으로 큰 리스크를 수반한다. 그러나 유전자 변형동물의 대부분은 마우스이며, 분자생물학적 관점에서 골재생의 과정을 이해하기 위해서는 마우스를 이용한 골재생 모델의 확립이 필요하다. 따라서 본 연구에서는 마우스를 통해 경조직 재생모델의 제작방법을 검토함과 동시에, 골재생부위에 대한 골질 (bone quality) 및 골양 (bone quantity) 평가의 방법을 수립하는 것을 목적으로 하였다. 골결손은 생후 8주의 마우스에 시술하였다. 치과용 드릴을 이용하여 경골 (tibia) 길이의 30 % 부근의 내측(medial) 면에서 골수강 (marrow cavity) 방향으로 $500\;{\mu}m\varphi$의 원주형 결손을 도입하였다. 시술 후의 골재생과정을 관찰하기 위해 ${\mu}CT$ (SMX-100CT: Simazu) 를 이용하여 주기적으로 촬영하였으며, 골양 (BV/TV) 의 회복과정은3D-bon (RATOC) 을 이용하여 정량적인 해석을 수행하였다. 그리고 재생부의 골질 (아파타이트 배행성; BAp orientation) 평가는 투과형micro-beam XRD (R-AXIS BQ: Rigaku)를 이용하여 수행하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.528-531
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• 2000

Deposition of PZT with UV laser ablatio was applied for realization of thin film sensors and actuators. Deposition rate of more than 20nm/min was attained by pulsed KrF excimer laser deposition, which is fairly better than those obtained by the other methods. Perovskite phase was obtained at room temperature deposition with Fast Atom Beam(FAB) treatment and annealing. Smart MEMS(Micro electro-mechanical system) is now a suject of interest in the field of micro optical devices, micro pumps, AFM cantilever devices etc. It can be fabricated by deposition of PZT thin films and micromachining. PZT films of more than 1 micron thickness is difficult to obtain by conventional methods. This is the reason why we applied excimer laser ablation for thin film deposition. The remanent polarization Pr of 700nm PZT thin film was measured, and the relative dielectric constant was determined to about 900 and the dielectric loss tangent was also measured to be about 0.04. XRD analysis shows that, after annealing at 650 degrees C in 1 hour, the perovskite structure would be formed with some amount of pyrochlore phase, as is the case of the annealing at 750 degrees C in 1 hour.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.10
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• pp.828-833
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• 2000

Growth characteristics and microstructure of AIN thin films grown by plasma assisted molecular beam epitaxy on Si substrates have been investigated. Growing temperature and substrate orientation were chosen as major variables of the experiment. Reflection high energy electron diffraction (RHEED), X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy/diffraction (TEM/TED) techniques were employed to characterize the micorstructure of the films. On Si(100) substrates, AlN thin films were grown along the hexagonal c-axis preferred orientation at temperature range 850-90$0^{\circ}C$. However on Si(111), the AlN films were epitaxially grown with directional coherency in AlN(0001)/Si(111), AlN(1100)/Si(110), and AlN(1120)/Si(112) at 85$0^{\circ}C$ and the epitaxial coherencry seemed to be slightly distorted with increasing temperature. The microstructure of AlN thin films on Si(111) substrates showed that the films include a lot of crystal defects and there exist micro-gaps among the columns.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.111-114
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• 2000

Growth characteristics and microstructure of AlN thin films grown by plasma assisted molecular beam epitaxy on Si substrates have been investigated. Growing temperature and substrate orientation were chosen as major variables of the experiment. Reflection high energy electron diffraction (RHEED), X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy/diffraction (TEM/TED) techniques were employed to characterize the microstructure of the films. On Si(100) substrates, AlN thin films were grown along the hexagonal c-axis preferred orientation at temperature range 850-90$0^{\circ}C$. However on Si(111), the AlN films were epitaxially grown with directional coherency in AlN(0001)/Si(111), AlN(1100)/Si(110), and AlN(1120)/Si(112) at 85$0^{\circ}C$ and the epitaxial coherencry seemed to be slightly distorted with increasing temperature. The microstructure of AlN thin films on Si(111) substrates showed that the films include a lot of crystal defects and there exist micro-gaps among the columns.

• Transactions on Electrical and Electronic Materials
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• v.10 no.4
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• pp.135-139
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• 2009

$H_2S$ micro-gas sensors have been developed employing $SnO_2$:CuO composite thin films. The films were prepared by e-beam evaporation of Sn and Cu metals on silicon substrates, followed by oxidation at high temperatures. Results of various studies, such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) reveal that $SnO_2$ and CuO are mutually non-reactive. The CuO grains, which in turn reside in the inter-granular regions of $SnO_2$, inhibit grain growth of $SnO_2$ as well as forming a network of p-n junctions. The film showed more than a 90% relative resistance change when exposed to $H_2S$ gas at 1 ppm in air at an operating temperature of $350^{\circ}C$ and had a short response time of 8 sec.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.364.1-364.1
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• 2016

We report the characteristics of individual ultra-long SnO2 nanowires(NWs) grown on sapphire(0001) substrates by vapor transport method. NWs, with typical lengths of >$400{\mu}m$, grew in the form of NW bundles under a hydrogen reducing atmosphere, without metal catalysts. The individual NWs were examined using high-resolution X-ray diffraction, transmission electron microscopy, and micro-Raman spectroscopy. The results revealed that the SnO2 NWs grew as high-quality, tetragonal-rutile-phase single crystals with mosaic distributions of $0.02^{\circ}$ and $0.026^{\circ}$ in the (101) and (110) planes, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.666-666
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• 2013

CIGS solar cell에서 p-type semiconductor역할을 수행하는 Cu(In,Ga)Se로 이루어진 Absorber layer는 4 element multi binary compound로 stoichiometry 측면에서 다양한 형태가 나타나기 때문에 태양전지 효율을 향상시키기 위해 이에 대한 연구가 활발하다. 우리는 E-beam evaporation 방법으로 다양한 조건의 multi layer로 증착된 CIG layer 위에 일정 두께의 Se을 증착하면서 열처리 조건에 따른 Selenization 메커니즘에 대한 연구를 수행하였다. 결과분석을 위해(in-situ High Temperature) XRD, XPS, Micro Raman spectroscopy, FE-SEM, (Nano Indentor, Atomic Force Microscopy) 등을 이용하여 결정구조, 결정화도, Depth profile, Eg (band gap energy) 등을 알아보고 분석결과간의 상관관계를 고찰하였다.