• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.4
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• pp.343-346
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• 2010

We have investigated growth of CdTe thin films by using (As, GaAs) buffer layers for application of large scale IR focal plane arrays(IFPAs). Buffer layers were grown by molecular beam epitaxy(MBE), which reduced the lattice mismatch of CdTe/Si and prevented native oxide on Si substrates. CdTe thin films were grown by metal organic chemical deposition system(MOCVD). As a result, polycrystalline CdTe films were grown on Si(100) and arsenic coated-Si(100) substrate. In other case, single crystalline CdTe(400) thin film was grown on GaAs coated-Si(100) substrate. Moreover, we observed hillock structure and mirror like surface on the (400) orientated epitaxial CdTe thin film.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.170-170
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• 1999

We studied Nb growth mode on Cu(100) surface by scanning tunneling microscopy (STM) at room temperature. Nb/Cu is immiscible at room temperature and thus is an ideal system for studying surface alloy formation. Initially deposited Nb atoms are incorporated subsurface on Cu(100). After annealing, they are preferentially found at step edges and appear as bright dots surrounded by dark rings. Ordering emerges from step edges as annealed. Ordered ({{{{ SQRT { 5} }$\times${{{{ SQRT { 5} }}}})R 26.6$^{\circ}$phase Nb structure is formed at $\theta$<0.2ML after annealing to 50$0^{\circ}C$. At higher coverage, $\theta$>0.25, annealing leads to p(2$\times$2) phase. due to large mismatch in lattice parameters, the domain is limited to a few tens of nm2. Growth kinetics of the system will be discussed.

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.486-492
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• 1998

Silicon carbide (SiC) thin films were deposited on the porous silicon substrates by chemical vapour de-position(CVD) using MTS as a source material. The deposited films were ${\beta}$-SiC with poor crystallity con-firmed by XRD measurement. It was considered that the films showed the mixed characteistics of cry-stalline and amorphous SiC where amorphous SiC where amorphous SiC played a role of buffer layer in interface between as-dep films and Si substrate. The buffer layer reduced lattice mismatch to some extent the generally occurs when SiC films are deposited on Si. The low temperature (10K) PL (phtoluminescence) studies showed two broad bands with peaks at 600 and 720 for the films deposited at 1100$^{\circ}C$ The maximum PL peak of the crystalline SiC was observed at 600 nm and the amrophous SiC of 720 nm was also confirmed. PL peak due the amorphous SiC was smaller than that of the crystalline SiC, PL of porous Si might be disapperared due to densification during heat treatment.

• Transactions on Electrical and Electronic Materials
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• v.12 no.3
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• pp.102-105
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• 2011

This work describes the characteristics of zinc oxide (ZnO) thin films formed on a polycrystalline (poly) 3C-SiC buffer layer using a sol-gel process. The deposited ZnO films were characterized using X-ray diffraction, scanning electron microscopy, and photoluminescence (PL) spectra. ZnO thin films grown on the poly 3C-SiC buffer layer had a nanoparticle structure and porous film. The effects of post-annealing on ZnO film were also studied. The PL spectra at room temperature confirmed the crystal quality and optical properties of ZnO thin films formed on the 3C-SiC buffer layer were improved due to close lattice mismatch in the ZnO/3C-SiC interface.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1337-1342
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• 2008

The whisker grows at the plating of a lead frame so that it causes the serious problem like the short. To prove this case, many people have studied the cause and influence of the tin whisker growth. This study explains the grain size affects the growth of the whisker in the lead frame. By these studies about the whisker, the whisker growth is discovered by stresses generated by the intermetallic compound and CTE mismatch in both plating and base metal. The stresses or lattice defect generated in the plating process changes grain structure of plating. Consequently, these various stresses are stabilized by forming unspecified whiskers through lots of grain boundaries. Because the grain boundary is the path of the whisker growth, the smaller grain size exists, the more whiskers grow.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.5
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• pp.497-501
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• 2004

The crystal structure of the GaN film on the AIN buffer layer grown by R. F sputtering with different thickness has been studied using X-ray scattering and transmission electron microscopy(TEM). The interface roughness between the AIN buffer layer and the epitaxial GaN film, due to crossover from planar to island grains, produced edge dislocations. The strain, coming from lattice mismatch between the AIN buffer layer and the epitaxial GaN film, produced screw dislocations. The density of the edge and screw dislocation propagating from the interface between the GaN film and the AIN buffer layer affected the electric resistance of GaN film.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.219-219
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• 2010

Silicides have been commonly used in the Si technology due to the compatibility with Si. Recently the silicide has been applied in solar cells [1] and nanoscale interconnects [2]. The modulation of Ni silicide phase is an important issue to satisfy the needs. The excellent electric-conductive nickel monosilicide (NiSi) nanowire has proven the low resistive nanoscale interconnects. Otherwise the Ni disilicide (NiSi2) provides a template to grow a crystalline Si film above it by the little lattice mismatch of 0.4% between Si and NiSi2. We present the formation of Ni silicide phases performed by the single deposition and the co-deposition methods. The co-deposition of Ni and Si provides a stable Ni silicide phase at a reduced processing temperature comparing to the single deposition method. It also discusses the Schottky contact formation between the Ni silicide and the grown crystalline Si film for the solar cell application.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.307-307
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• 2011

Graphene is the hottest topic in condensed-matter physics due to its unusual electronic structures such as Dirac cones and massless linear dispersions. Graphene can be epitaxially grown on various metal surfaces with chemical vapor deposition processes. Such epitaxial graphene shows modified electronic structures caused by substrates. Here, local geometric and electronic structures of graphene grown on Ru(0001) will be presented. Scanning tunneling microscopy (STM) and spectroscopy (STS) was used to reveal energy dependent atomic level topography and position-dependent differential conductance spectra. Both topography and spectra show variations from three different locations in rippled structures caused by lattice mismatch between graphene and substrate. Based on the observed results, structural models for graphene on Ru(0001) system were considered.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.65-66
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• 2000

Various fluoride films on a glass substrate were prepared and characterized to provide a seed layer for crystalline Si film growth. The XRD analysis on $CaF_2/glass$ illustrated (220) preferential orientation and showed lattice mismatch less than 5 % with Si. We achieved a fluoride film with breakdown electric field of 1.27 MV/cm, leakage current density about $10^{-6}$ $A/cm^2$, and relative dielectric constant less than 5.6. This paper demonstrates microcrystalline silicon $({\mu}c-Si)$ film growth by using a $CaF_2/glass$ substrate. The ${\mu}c-Si$ films exhibited crystallization in (111) and (220) planes, grain size of $700\;{\AA}$, crystalline volume fraction over 65 %, dark- and photo-conductivity ratio of 124, activation energy of 0.49 eV, and dark conductivity less than $4{\times}10^{-7}$ S/cm.

• Journal of the Korean Ceramic Society
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• v.36 no.4
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• pp.366-371
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• 1999

The effect of VC addition on the microstructural evolution of Fe-TiC cermet has been investigated. The microstructures of the Fe-TiC varied with the amount of VC addition. The addition of 1wt% VC enhanced the instability of liquid-solid interface ; the dissolving interface showed round shape instead of facetted one which was ascribed to the increase of lattice mismatch between TiC and solid-solution carbide. in the speci-men with 10wt% VC the new set of solid-solution carbide grains of uniform and small size was formed in-side coarse TiC particles by diffusion induced recrystallizatin (DIR). With increasing the heat-treatment time fine recrystallized grains were dispersed homogeneously in the matrix and resulted in the increase in fracture strength.