• Journal of the Semiconductor & Display Technology
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• v.11 no.3
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• pp.63-67
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• 2012

The films were deposited at evaporator system and were annealed at heat treatment. The films had a dense microstructure with fine grains. The electrical properties of the films were dramatically controlled with annealing. Samples Preparation were analyzed in term of positive temperature coefficient of Resistivity Samples were made in the substrate tempera-true of $400^{\circ}C$ deposition time of 10 hours, and forward power of 210watt. R-T(resistivity-temperature) Characteristics of the samples were investigated as a function of the substrate type and the ambient temperature. The resistivity of the thin film specimens was compared with that of the bulk type specimens. By using RF/DC magnetron sputtering system, we obtained lower resistivity in the thermistor with thin $BaTiO_3$ film than that in the bulk type thermistor.

• 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.

• Solar Energy
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• v.20 no.2
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• pp.55-65
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• 2000

Better electrical and optical properties of ITO thin films were demanded for the window layer of CdS/CdTe solar cells. To match that demand, an ion beam sputtering system was used for the deposition of ITO thin films. The substrate temperature and ion beam energy were controlled to deposit high quality ITO thin films in two cases of Ar ion sputtering and Ar+$O_2$ ion sputtering. The microstructure changed from domain structure in ITO deposited by Ar ions to grain structure in ITO deposited by Ar+$O_2$ ions. The lowest resistivity of ITO films was $1.5\times10^{-4}{\Omega}cm$ at $100^{\circ}C$ substrate temperature in case of Ar ions sputtering. Transmittance in the visible range was over 80% above $100^{\circ}C$ substrate temperature.

• Current Applied Physics
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• v.18 no.11
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• pp.1240-1247
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• 2018

Magnetic hysteresis in Ni nanowire arrays grown by electrodeposition inside the pores of anodic alumina templates is studied as a function of temperature in the range between 5 K and 300 K. Nanowires with different diameters, aspect ratios, inter-wire distance in the array and surface condition (smooth and rough) are synthesized. These microstructure parameters are linked to the different free magnetic energy contributions determining coercivity and the controlling magnetization reversal mechanisms. Coercivity increases with temperature in arrays of nanowires with rough surfaces and small diameters -33 nm and 65 nm- when measured without removing the alumina template and/or the Al substrate. For thicker wires -200 nm in diameter and relatively smooth surfaces- measured without the Al substrate, coercivity decreases as temperature rises. These temperature dependences of magnetic hysteresis are described in terms of an effective magnetic anisotropy $K_a$, resulting from the interplay of magnetocrystalline, magnetoelastic and shape anisotropies, together with the magnetostatic interaction energy density between nanowires in the array. The experimentally determined coercive fields are compared with results of micromagnetic calculations, performed considering the magnetization reversal mode acting in each studied array and microstructure parameters. A method is proposed to roughly estimate the value of $K_a$ experimentally, from the hysteresis loops measured at different temperatures. These measured values are in agreement with theoretical calculations. The observed temperature dependence of coercivity does not arise from an intrinsic property of pure Ni but from the nanowires surface roughness and the way the array is measured, with or without the alumina template and/or the aluminum support.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.05a
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• pp.42-45
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• 1992

The poly silicon thin films were prepared by solid phase crystallization at 600$^{\circ}C$ of amorphous silicon films deposited on Corning 7059 glass and (100) silicon wafer with thermally grown SiO$_2$substrate by plasma enhanced chemical vapor deposition with varying rf power, deposition temperature, total flow rate. Crystallization time, microstructure, absorption coefficients were investigated by RAMAN, XRD analysis and UV transmittance measurement. Crystallization time of amorphous silicon films was increased with increasing rf power, decreasing deposition temperature and decreasing total flow rate.

• Tribology and Lubricants
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• v.28 no.2
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• pp.56-61
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• 2012

In order to investigate the possibility of Ni-Al based intermetallics coating onto aluminum substrate, the coating process for induction heating has been evaluated by microscopically analyzing the intermetallic layers coated at temperatures lower than the melting temperature of aluminum. The coating layers were divided into two parts with different microstructure along the depth. Hard $NiAl_3$ layer was found at lower parts of the coatings near the interface with aluminum substrate. This layer was formed by the diffusion of aluminum atoms from the substrate into the coating layer across the interface during the induction heating. Meanwhile, at the upper parts of the coating near the surface, a large amount of un-reacted Ni was still remained and surrounded by several Ni-Al based intermetallic compounds, such as $Ni_3Al$, NiAl and $Ni_2Al_3$ formed by the lattice diffusion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.16-22
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• 2008

We fabricated thermally-evaporated 10 nm-Ni/30 nm and 70 nm Poly-Si/200 nm-$SiO_2/Si$ structures to investigate the thermal stability of nickel silicides formed by rapid thermal annealing(RTA) of the temperature of $300{\sim}1100^{\circ}C$ for 40 seconds. We employed for a four-point tester, field emission scanning electron microscope(FE-SEM), transmission electron microscope(TEM), high resolution X-ray diffraction(HRIXRD), and scanning probe microscope(SPM) in order to examine the sheet resistance, in-plane microstructure, cross-sectional microstructure evolution, phase transformation, and surface roughness, respectively. The silicide on 30 nm polysilicon substrate was stable at temperature up to $900^{\circ}C$, while the one on 70 nm substrate showed the conventional $NiSi_2$ transformation temperature of $700^{\circ}C$. The HRXRD result also supported the existence of NiSi-phase up to $900^{\circ}C$ for the Ni silicide on the 30 nm polysilicon substrate. FE-SEM and TEM confirmed that 40 nm thick uniform silicide layer and island-like agglomerated silicide phase of $1{\mu}m$ pitch without residual polysilicon were formed on 30 nm polysilicon substrate at $700^{\circ}C\;and\;1000^{\circ}C$, respectively. All silicides were nonuniform and formed on top of the residual polysilicon for 70 nm polysilicon substrates. Through SPM analysis, we confirmed the surface roughness was below 17 nm, which implied the advantage on FUSI gate of CMOS process. Our results imply that we may tune the thermal stability of nickel monosilicide by reducing the height of polysilicon gate.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2000.04a
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• pp.109-109
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• 2000

Recently, carbon nanotube has been investigating for field emission display ( (FED) applications due to its high electron emission at relatively low electric field. However, the growing of carbon nanotube generally requires relatively high temperature processing such as arc-discharge (5,000 ~ $20,000^{\circ}C$) and laser evaporation (4,000 ~ $5,000^{\circ}C$) methods. In this presentation, low temperature growing of carbon nanotube by plasma enhanced chemical vapor deposition (PECVD) using nickel catalyst which is compatible to conventional FED processing temperature will be described. Carbon n notubes with average length of 100 run and diameter of 2 ~ $3\mu$ill were successfully grown on silicon substrate with native oxide layer at $550^{\circ}C$using nickel catalyst. The morphology and microstructure of carbon nanotube was highly depended on the processing temperature and nickel layer thickness. No significant carbon nanotube growing was observed with samples deposited on silicon substrates without native oxide layer. This is believed due to the formation of nickel-silicide and this deteriorated the catalytic role of nickel. The formation of nickel-silicide was confirmed by x-ray analysis. The role of native oxide layer and processing parameter dependence on microstructure of low temperature grown carbon nanotube, characterized by SEM, TEM XRD and R없nan spectroscopy, will be presented.

• Korean Journal of Metals and Materials
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• v.46 no.3
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• pp.159-168
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• 2008

Thermally-evaporated 10 nm-Ni/1 nm-Ru/(30 nm or 70 nm-poly)Si structures were fabricated in order to investigate the thermal stability of Ru-inserted nickel monosilicide. The silicide samples underwent rapid thermal anne aling at $300{\sim}1,100^{\circ}C$ for 40 seconds. Silicides suitable for the salicide process were formed on the top of the single crystal and polycrystalline silicon substrates mimicking actives and gates. The sheet resistance was measured using a four-point probe. High resolution X-ray diffraction and Auger depth profiling were used for phase and chemical composition analysis, respectively. Transmission electron microscope and scanning probe microscope(SPM) were used to determine the cross-sectional structure and surface roughness. The silicide, which formed on single crystal silicon and 30 nm polysilicon substrate, could defer the transformation of $Ni_2Si $i and $NiSi_2 $, and was stable at temperatures up to $1,100^{\circ}C$ and $1,100^{\circ}C$, respectively. Regarding microstructure, the nano-size NiSi preferred phase was observed on single crystalline Si substrate, and agglomerate phase was shown on 30 nm-thick polycrystalline Si substrate, respectively. The silicide, formed on 70 nm polysilicon substrate, showed high resistance at temperatures >$700^{\circ}C$ caused by mixed microstructure. Through SPM analysis, we confirmed that the surface roughness increased abruptly on single crystal Si substrate while not changed on polycrystalline substrate. The Ru-inserted nickel monosilicide could maintain a low resistance in wide temperature range and is considered suitable for the nano-thick silicide process.

• Journal of Powder Materials
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• v.19 no.5
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• pp.343-347
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• 2012

In this study, an oxygen plasma treatment was used as a low temperature debinding method to form a conductive copper feature on a flexible substrate using a direct printing process. To demonstrate this concept, conductive copper patterns were formed on polyimide films using a copper nanoparticle-based paste with polymeric binders and dispersing agents and a screen printing method. Thermal and oxygen plasma treatments were utilized to remove the polymeric vehicle before a sintering of copper nanoparticles. The effect of the debinding methods on the phase, microstructure and electrical conductivity of the screen-printed patterns was systematically investigated by FE-SEM, TGA, XRD and four-point probe analysis. The patterns formed using oxygen plasma debinding showed the well-developed microstructure and the superior electrical conductivity compared with those of using thermal debinding.