• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.125-129
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• 2016

In this study, we have investigated a high-temperature AlN nucleation layer and AlGaN epilayers on c-plane sapphire substrate by low-pressure metal-organic chemical vapor deposition (LP-MOCVD). High resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), scanning electron microscope (SEM) and Raman scattering measurements have been exploited to study the crystal quality, surface morphology, and residual strain of the HT-AlN nucleation layer. These analyses reveal that the insertion of an LT-AlN nucleation layer can improve the crystal quality, smooth the surface morphology of the HT-AlN nucleation layer and further reduce the threading dislocation density of AlGaN epifilms. The mechanism of inserting an LT-AlN nucleation layer to enhance the optical properties of HT-AlN nucleation layer and AlGaN epifilm are discussed from the viewpoint of driving force of reaction in this paper.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.8
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• pp.575-579
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• 2012

Heteroepitaxial InP films have been grown on GaAs substrates to study the effects of the nucleation layer's surface roughness on the epitaxial layer's quality. For this, InP nucleation layers were grown at $400^{\circ}C$ with various ethyldimethylindium (EDMIn) flow rates and durations of growth, annealed at $6200^{\circ}C$ for 10 minutes and then InP epitaxial layers were grown at $550^{\circ}C$. It has been found that the nucleation layer's surface roughness is a critical factor on the epitaxial layer's quality. When a nucleation layer is grown with an EDMIn flow rate of 2.3 ${\mu}mole/min$ for 12 minutes, the surface roughness of the nucleation layer is minimum and the successively grown epitaxial layer's qualities are comparable to those of the homoepitaxial InP layers reported. The minimum full width at half maximum of InP (200) x-ray diffraction peak and that of near-band-edge peak from a 4.4 K photoluminescence are 60 arcmin and 6.33 meV, respectively.

• Journal of the Korean Ceramic Society
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• v.41 no.6
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• pp.435-438
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• 2004

MOCVD is one of the major deposition techniques for Cu thin films and Ta-Si-N is one of promising barrier metal candidates for Cu with high thermal stability. Effects of hydrogen plasma pretreatment of the underlying Ta-Si-N film surface on the Cu nucleation in Cu MOCVD were investigated using scanning electron microscopy, X-ray photoelectron spectroscopy and Auger electron emission spectrometry analyses. Cu nucleation in MOCVD is enhanced as the rf-power and the plasma exposure time are increased in the hydrogen plasma pretreatment. The optimal plasma treatment process condition is the rf-power of 40 Wand the plasma exposure time of 2 min. The hydrogen gas flow rate in the hydrogen plasma pretreatment process does not affect Cu nucleation much. The mechanism through which Cu nucleation is enhanced by the hydrogen plasma pretreatment of the Ta-Si-N film surface is that the nitrogen and oxygen atoms at the Ta-Si-N film surface are effectively removed by the plasma treatment. Consequently the chemical composition was changed from Ta-Si-N(O) into Ta-Si at the Ta-Si-N film surface, which is favorable for Cu nucleation.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.246-246
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• 2010

As the trench width in the interconnect technology decreases down to nano-scale below 50 nm, superconformal gap-filling process of Cu becomes very critical for Cu interconnect. Obtaining superconfomral gap-filling of Cu in the nano-scale trench or via hole using MOCVD is essential to control nucleation and growth of Cu. Therefore, nucleation of Cu must be suppressed near the entrance surface of the trench while Cu layer nucleates and grows at the bottom of the trench. In this study, suppression of Cu nucleation was achieved by treating the Ru barrier metal surface with capacitively coupled hydrogen plasma. Effect of hydrogen plasma pretreatment on Cu nucleation was investigated during MOCVD on atomic-layer deposited (ALD)-Ru barrier surface. It was found that the nucleation and growth of Cu was affected by hydrogen plasma treatment condition. In particular, as the plasma pretreatment time and electrode power increased, Cu nucleation was inhibited. Experimental data suggests that hydrogen atoms from the plasma was implanted onto the Ru surface, which resulted in suppression of Cu nucleation owing to prevention of adsorption of Cu precursor molecules. Due to the hydrogen plasma treatment of the trench on Ru barrier surface, the suppression of Cu nucleation near the entrance of the trenches was achieved and then led to the superconformal gap filling of the nano-scale trenches. In the case for without hydrogen plasma treatments, however, over-grown Cu covered the whole entrance of nano-scale trenches. Detailed mechanism of nucleation suppression and resulting in nano-scale superconformal gap-filling of Cu will be discussed in detail.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.8
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• pp.1793-1798
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• 2005

We model the nucleation and motion of defects in the liquid crystal display device with inhomogeneous surface by using fast Q-tensor method, which can calculate scalar order parameter S and nucleation of the defect in the liquid crystal director field. In order to model the defect, homeotropic aligned liquid crystal cell with step inhomogeneous electrode which has a height of $1{\mu}m$ is used. From the simulation, we can observe the nucleation and line of the defect from surface inhomogeneity and the experiment is performed for confirmation.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1159-1162
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• 2004

A modeling of the nucleation and dynamical behavior of defects from an inhomogeneous surface configuration using fast Q-tensor method is realized. On modeling the defect nucleation and dynamics, A fast Q-tensor method is applied. From the numerical modeling, we confirmed that surface inhomogeneity which makes strong strain energy in the local liquid crystal director field could cause defects. Experimental result has compared with numerical modeling in order to verify the simulation of the defect nucleation.

• Journal of Industrial Technology
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• v.29 no.B
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• pp.115-119
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• 2009

Green fluorescent protein (GFPuv) was displayed on the surface of ethanol-producing bacteria Zymomonas mobilis using N-terminal domain of ice nucleation protein (INP) as an anchoring motif. To evaluate the ice nucleation protein as plausible anchor motif in Z. mobilis, GFPuv gene was subcloned into Zymomonas expression vector yielding pBBR1MCS-3/pPDC/INPN/GFPuv plasmid., INP-GFPuv fusion protein was expressed in Z. mobilis and its fluorescence was verified by confocal microscopy. The successful display of GFPuv on Zymomonas mobilis suggest that INP anchor motif could be used for future fusion partner in Z. mobilis strain improvement.

• Korean Journal of Materials Research
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• v.14 no.5
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• pp.363-367
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• 2004

Recently ZnO epitaxial layers have been widely studied as a semiconductor material for optoelectronic devices. Sapphire and silicon are commonly selected as substrate materials for ZnO epitaxial growth. In this communication, we report the effect of the ECR plasma pretreatment of sapphire and silicon substrates on the nucleation in the ZnO ALE (atomic layer epitaxy). It was found that ECR plasma pretreatment reduces the incubation period of the ZnO nucleation. Oxygen ECR plasma enhances ZnO nucleation most effectively since it increases the hydroxyl group density at the substrate surface. The nucleation enhancing effect of the oxygen ECR plasma treatment is stronger on the sapphire substrate than on the silicon substrate since the saturation density of the hydroxyl group is lower at the sapphire surface than that at the silicon surface.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.303-306
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• 1999

On the effect of substrate bias at first stage of diamond synthesis at lower substrate temperature(approximately 673K) using microwave plasma CVD and effect of reaction gas system for the bias enhanced nucleation were studied. The reaction gas was mixture of methane and hydrogen or carbon monoxide and hydrogen. The nucleation density of applied bias -150V using $CH_4-H_2$ reaction gas system, significantly higher than that of $C-H_2$ reaction gas system. When the $CH_4-H_2$ reaction was used, nucleation density was increased because of existence of SiC as a interface for diamond nucleation. By use of this negative bias effect for fabrication of CVD diamond film using two-step diamond growth without pre-treatment, fabrication of the diamond film consist of diamond grains $0.2\mu\textrm{m}$ in diameter was demonstrated

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.4
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• pp.164-168
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• 2003

The initial stage of copper electrodeposition has been known to be very important role for morphology and physical properties after final growth. The factors affecting the nucleation are electrode, current density, electrolyte and temperature. Current studies has illuminated the initial nucleation of copper electrodeposition in the viewpoint of the surface status of electrode and analyzed using EIS and SEM observation