• Journal of the Korean Vacuum Society
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• v.11 no.3
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• pp.159-165
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• 2002

The physical properties of the TiN films deposited by ALD using $TiCl_4$and $NH_3$have been investigated. The TiN deposition rate is ~0.6 $\AA$ under an optimum deposition condition and the resistivity of the TiN films is 200~350 $\mu\Omega$cm . According to the XRD analysis results TiN films are crystallized in the ALD process window. AES analysis results show that the Cl impurity concentration in the TiN films is lower than 1 at% and that the atomic ratio of the TiN films is 1:1. Also it is found by SEM observation that the step coverage of the TiN films on which TiN films with trenches the aspect ratio of which is 10:1 is excellent.

• Journal of the Korean institute of surface engineering
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• v.53 no.4
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• pp.169-181
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• 2020

The ferroelectricity in emerging fluorite-structure oxides such as HfO₂ and ZrO₂ has attracted increasing interest since 2011. Different from conventional ferroelectrics, the fluorite-structure ferroelectrics could be reliably scaled down below 10 nm thickness with established atomic layer deposition technique. However, defects such as carbon, hydrogen, and nitrogen atoms in fluorite-structure ferroelectrics are reported to strongly affect the nanoscale polymorphism and resulting ferroelectricity. The characteristic nanoscale polymorphism and resulting ferroelectricity in fluorite-structure oxides have been reported to be influenced by defect concentration. Moreover, the conduction of charge carriers through fluorite-structure ferroelectrics is affected by impurities. In this review, the origin and effects of various kinds of defects are reviewed based on existing literature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.3
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• pp.196-200
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• 2019

In this study, photoluminescence (PL) analysis was performed to evaluate the optical properties of commercial ZnO substrates. Particular attention was paid to the bound exciton (BX) luminescence, which is usually the strongest emission intensity of commercial substrates. At 15 K, PL analysis revealed that the BX peak due to donor-type impurities (donor-bound-exciton; DX) dominated, while two-electron satellite (TES) emission, donor-accepter pair (DAP) emission, and LO-phonon replica emission were also observed. The impurity concentration of the ZnO substrate was determined to be $10^{15}$ to $10^{16}/cm^3$ by examination of the temperature variation of DAP, while the half width and intensity change of the luminescence revealed that the temperature change of BX can be interpreted almost the same as the analysis of free-exciton emission.

• Journal of Ceramic Processing Research
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• v.19 no.5
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• pp.439-443
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• 2018

The outstanding characteristics of high quality GaN single crystal substrates make it possible to apply the manufacture of high brightness light emitting diodes and power devices. However, it is very difficult to obtain high quality GaN substrate because the process conditions are hard to control. In order to effectively control the formation of GaN polycrystals during the bulk GaN single crystal growth by the HVPE (hydride vapor phase epitaxy) method, a quartz ring was introduced in the edge of substrate. A variety of evaluating method such as high resolution X-ray diffraction, Raman spectroscopy and photoluminescence was used in order to measure the effectiveness of the quartz ring. A secondary ion mass spectroscopy was also used for evaluating the variations of impurity concentration in the resulting GaN single crystal. Through the detailed investigations, we could confirm that the introduction of a quartz ring during the GaN single crystal growth process using HVPE is a very effective strategy to obtain a high quality GaN single crystal.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.39.2-39.2
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• 2010

In this work we have investigated electrical and optical properties of interface for ITO/Si with shallow doped emitter. The ITO is prepared by DC magnetron sputter on p-type monocrystalline silicon substrate. As an experimental result, The transmittance at 640nm spectra is obtained an average transmittance over 85% in the visible range of the optical spectrum. The energy bandgap of ITO at oxygen flow from 0% to 4% obtained between 3.57eV and 3.68eV (ITO : 3.75eV). The energy bandgap of ITO is depending on the thickness, sturcture and doping concentration. Because the bandgap and position of absorption edge for degenerated semiconductor oxide are determined by two competing mechanism; i) bandgap narrowing due to electron-electron and electron-impurity effects on the valance and conduction bands (> 3.38eV), ii) bandgap widening by the Burstein-Moss effect, a blocking of the lowest states of the conduction band by excess electrons( < 4.15eV). The resistivity of ITO layer obtained about $6{\times}10^{-4}{\Omega}cm$ at 4% of oxygen flow. In case of decrease resistivity of ITO, the carrier concentration and carrier mobility of ITO film will be increased. The contact resistance of ITO/Si with shallow doped emitter was measured by the transmission line method(TLM). As an experimental result, the contact resistance was obtained $0.0705{\Omega}cm^2$ at 2% oxygen flow. It is formed ohmic-contact of interface ITO/Si substrate. The emitter series resistance of ITO/Si with shallow doped emitter was obtained $0.1821{\Omega}cm^2$. Therefore, As an PC1D simulation result, the fill factor of EWT solar cell obtained above 80%. The details will be presented in conference.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.2
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• pp.89-95
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• 1995

The structure of boron ion-implanted pn junctio in the vacancy-doped p-type HgCdTe was investigated with the differential Hall measurement. The as-implanted junction showed the electron concentration as high as 1${\times}10^{18}/cm^{3}$ and the junction depth of 0.6.mu.m. When the HgCdTe junction was heated in oven, the electron concentration near the junction decreased and the junction depth increased as the annealing temperature and time increased. The junction structure after the thermal annealing was n$^{+}$/n$^{-}$/p. For the 200.deg. C 20min annealed sample, the electron mobility was 10$^{4}cm^{2}/V{\cdot}$s near the surface(n$^{+}$), and was larger thatn 10$^{5}cm^{2}/V{\cdot}$s near the junction(n$^{+}$). The junction formation mechanism is conjectured as follows. When HgCdTe is ion-implanted, the ion energy generates crystal defecis and displaced Hg atoms HgCdTe is ion-implanted, the ion energy generates crystal defecis and displaced Hg atoms near the surface. The displaced Hg vacancies diffuse in easily by the thernal treatment and a fill the Hg vacancies in the p-HgCdTe substrate. With the Hg vacancies filled completely, the GfCdTe substrate becomes n-type because of the residual n-type impurity which was added during the wafer growing. Therefore, the n$^{+}$/n$^{-}$/p regions are formed by crystal defects, residual impurities, and Hg vacancies, respectively.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.512-515
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• 2008

The removal of iron from neodymium chloride solution was carried out by solvent extraction using Alamine 336 in kerosine. The effect of Alamine 336, hydrochloric acid and chloride ion concentrations on the extraction of Fe were studied. The results showed that Alamine 336 as an extractant for removal of iron was effective and the extraction percentage of iron was increased with increasing hydrochloric acid and chloride ion concentration in aqueous solution. The extraction of 99% of iron is attained at a ratio of A/O = 4 by distilled water. The stripping yield of iron from loaded Alamine 336 decreased with decreasing hydrochloric acid concentration in stripping solution.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.12
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• pp.80-90
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• 1994

To develop VLSI of higher packing density with 0.5.mu.m gate length of less, semiconductor devices require shallow junction with higher doping concentration. the most common method to form the shallow junction is ion implantation, but in order to remove the implantation induced defect and activate the implanted impurities electrically, ion-implanted Si should be annealed at high temperature. In this annealing, impurities are diffused out and redistributed, creating deep PN junction. These make it more difficult to form the shallow junction. Accordingly, to miimize impurity redistribution, the thermal-budget should be kept minimum, that is. RTA needs to be used. This paper reports results of the diffusion characteristics of PSG film by varying Phosphorus weitht %/ Times and temperatures of RTA. From the SIMS.ASR.4-point probe analysis, it was found that low sheet resistance below 100 .OMEGA./ㅁand shallow junction depths below 0.2.mu.m can be obtained and the surface concentrations are measured by SIMS analysis was shown to range from 2.5*10$^{17}$ aroms/cm$^{3}$~3*10$^{20}$ aroms/cm$^{3}$. By depending on the RTA process of PSG film on Si, LDD-structured nMOSFET was fabricated. The junction depths andthe concentration of n-region were about 0.06.mu.m. 2.5*10$^{17}$ atom/cm$^{-3}$ , 4*10$^{17}$ atoms/cm$^{-3}$ and 8*10$^{17}$ atoms/cm$^{3}$, respectively. As for the electrical characteristics of nMOS with phosphorus junction for n- region formed by RTA, it was found that the characteristics of device were improved. It was shown that the results were mainly due to the reduction of electric field which decreases hot carriers.

• KSBB Journal
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• v.15 no.2
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• pp.208-213
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• 2000

Using three types of porcelain clays such as White, Blue, and Yellow clays, which were used as raw materials for Bae씨a, C Chungja, and common porcelains, the biological refinement by an enrichment culture of iron reducing bacteria was studied. | In the biological clay refining, amounts of leached iron increased as increasing sucrose $\infty$ncentration, which was s supplemented as a carbon and electron donor source for cell growth and iron reduction. Total amounts of the leached iron a and specific rate of iron reduction were dependent on the types of the clay. Strength and chromaticity of refined clays which a are important properties required for porcelain clays were improved as increasing sucrose concentration. The degree of s shrinking, however, did not changed. the redness among the chromaticity of refined clays is favorably reduced through the r ripening by the iron reducing bacteria. Considering iron removal efficiency and the change of physical properties, the optimal c concentration of sucrose was 4%(w/w) in the clay.

• Journal of the Korean institute of surface engineering
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• v.47 no.5
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• pp.227-232
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• 2014

In this study, we propose the application of doping process technology for atmospheric pressure plasma. The plasma treatment means the wafer is warmed via resistance heating from current paths. These paths are induced by the surface charge density in the presence of illuminating Argon atmospheric plasmas. Furthermore, it is investigated on the high-concentration doping to a selective partial region in P type solar cell wafer. It is identified that diffusion of impurities is related to the wafer temperature. For the fixed plasma treatment time, plasma currents were set with 40, 70, 120 mA. For the processing time, IR(Infra-Red) images are analyzed via a camera dependent on the temperature of the P type wafer. Phosphorus concentrations are also analyzed through SIMS profiles from doped wafer. According to the analysis for doping process, as applied plasma currents increase, so the doping depth becomes deeper. As the junction depth is deeper, so the surface resistance is to be lowered. In addition, the surface charge density has a tendency inversely proportional to the initial phosphorus concentration. Overall, when the plasma current increases, then it becomes higher temperatures in wafer. It is shown that the diffusion of the impurity is critically dependent on the temperature of wafers.