• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.79-82
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• 1989

We studied the epitaxial growth of GaAs/GaAs and GaAs/Si by Laser CVD with 193nm ArF pulsed excimer laser. The source gases of TMGa and AsC13 or TMGa-TMAs adducts are mixed with H2, and photolyzed above the substrate which is heated up to around 300$^{\circ}C$. Then the photolyzed atoms are deposited on the silicon or GaAs substrate. The deposited films are analyzed with ESKA depth profiling and X-ray differaction method, which shows that the films on Si and GaAs are stoichiometric and crystalized at such a low temperature. We show a clear evidence for the epitaxial growth of GaAs on Si or GaAs on GaAs at low temperature by excimer laser CVD.

• Korean Journal of Materials Research
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• v.21 no.5
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• pp.268-272
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• 2011

Due to their novel properties, GaN based semiconductors and their nanostructures are promising components in a wide range of nanoscale device applications. In this work, the gallium nitride is deposited on c-axis oriented sapphire and porous SWCNT substrates by molecular beam epitaxy using a novel single source precursor of $Me_2Ga(N_3)NH_2C(CH_3)_3$ with ammonia as an additional source of nitrogen. The advantage of using a single molecular precursor is possible deposition at low substrate temperature with good crystal quality. The deposition is carried out in a substrate temperature range of 600-750$^{\circ}C$. The microstructural, structural, and optical properties of the samples were analyzed by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and photoluminescence. The results show that substrate oriented columnar-like morphology is obtained on the sapphire substrate while sword-like GaN nanorods are obtained on porous SWCNT substrates with rough facets. The crystallinity and surface morphology of the deposited GaN were influenced significantly by deposition temperature and the nature of the substrate used. The growth mechanism of GaN on sapphire as well as porous SWCNT substrates is discussed briefly.

• Journal of the Korean Vacuum Society
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• v.19 no.5
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• pp.371-376
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• 2010

The GaAs epitaxial layers were grown on Si(100) substrates by molecular beam epitaxy (MBE) using the two-step method. The Si(100) substrates were cleaned with three different surface cleaning methods of vacuum heating, As-beam exposure, and Ga-beam deposition at the substrate temperature of $800^{\circ}C$ in the MBE growth chamber. Growth temperature and thickness of the GaAs epitaxial layer were $800^{\circ}C$ and $1{\mu}m$, respectively. The surface structure and properties were investigated by reflection high-energy electron diffraction (RHEED), AFM (Atomic force microscope), DXRD (Double crystal x-ray diffraction), PL (Photoluminescence), and PR (Photoreflectance). From RHEED, the surface structure of GaAs epitaxial layer grown on Si(100) substrate with Ga-beam deposition is ($2{\times}4$). The GaAs epitaxial layer grown on Si(100) substrate with Ga-beam deposition has a high quality.

• Journal of the Korean Vacuum Society
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• v.9 no.2
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• pp.116-121
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• 2000

We measured surface photovoltage (SPV) of $Al_{0.24}Ga_{0.76}As/GaAs$ epilayer grown by molecular beam epitixy (MBE). The band gap energies of $Al_{0.24}Ga_{0.76}As/GaAs$ epilayer, GaAs substrate and buffer layer obtained from SPV signals are 1.70, 1.40 and 1.42 eV, respectively. There results are in good agreements with photoreflectance (PR) measurement. The measured SPV intensity of GaAs substrate is three times larger than $Al_{0.24}Ga_{0.76}$Asepilayer by carrier mobility difference. The parameters of Varshni equation were determined from the SPV spectra as a function of temperature.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.2
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• pp.41-46
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• 2020

The characteristics of the residual stress on the types of the substrate was investigated with adjusting the V/III ratio during GaN growth via the HVPE method. GaN single crystal layers were grown on a sapphire substrate and a GaN template under the conditions of V/III ratio 5, 10, and 15, respectively. During GaN growth, multiple hexagonal pits in GaN single crystal were differently revealed in accordance with growth condition and substrate type, and their distribution and depth were measured via optical microscopy(OM) and white light interferometry(WLI). As a result, it was confirmed that the distribution area and depth of hexagonal pit tended to increase as the V/III ratio increased. Moreover, it was found that the residual stress in GaN single crystal decreased as the distribution area and depth of the pit increased through measuring micro Raman spectrophotometer. In the case of GaN growth according to substrate type, the GaN on GaN template showed lower residual stress than the GaN grown on sapphire substrate.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.3
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• pp.67-71
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• 2014

An attempt to grow high quality GaN on silicon substrate using metal organic chemical vapor deposition (MOCVD), herein GaN epitaxial layers were grown on various Si(111) substrates. Thin Platinum layer was deposited on Si(111) substrate using sputtering, followed by thermal annealing to form Pt nano-clusters which act as masking layer during dry-etched with inductively coupled plasma-reactive ion etching to generate nano-patterned Si(111) substrate. In addition, micro-patterned Si(111) substrate with circle shape was also fabricated by using conventional photo-lithography technique. GaN epitaxial layers were subsequently grown on micro-, nano-patterned and conventional Si (111) substrate under identical growth conditions for comparison. The GaN layer grown on nano-patterned Si (111) substrate shows the lowest crack density with mirror-like surface morphology. The FWHM values of XRD rocking curve measured from symmetry (002) and asymmetry (102) planes are 576 arcsec and 828 arcsec, respectively. To corroborate an enhancement of the growth quality, the FWHM value achieved from the photoluminescence spectra also shows the lowest value (46.5 meV) as compare to other grown samples.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2247-2252
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• 2012

In this paper, we produced CIGS thin film by co-evaporation method. During the process, substrate temperature and Ga/(In+Ga) composition ratio was altered to observe the change of resistivity and absorbance spectra measurements. As substrate temperature increased, resistivity decreased and as Ga/(In+Ga) composition ratio increased from 0.30 to 0.72, band gap also increased with the range of 1.26eV, 1.30eV, 1.43eV, 1.47eV. With the constant condition of composition ratio, resistivity decreased with increased thickness of the thin film. On this experiment, we assumed that optical absorbance ratio and optical current will be increased with CIGS thin film fabrication.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.6
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• pp.34-40
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• 1985

Characteristics of GaAE epilayers grown on (100) CaAs wa(tors by molecular beam epitaxy (MBE) under various single crystal growing conditions were investigated. In fabrica-ting GaAs, epilayer by MBE, the most important factors are a substrate temperature(ts) and a flux density ratio (As/Ga). In this experiment, the substrate temperature was varied in the range of 48$0^{\circ}C$ to $650^{\circ}C$ and As and Ga cell temperatures were varied in the range of 218$^{\circ}C$ to 256$^{\circ}C$ and 876$^{\circ}C$ to 98$0^{\circ}C$, respectively. At the substrate temperature of 54$0^{\circ}C$, As cell temperature of 23$0^{\circ}C$, and Ga cell temperature of 91$0^{\circ}C$, the As/Ga ratio was 5"10, the surface morphology was most smooth . Investigation of As-stabilized surface by RHEED and of depth profile by SIM5 showed that As is less stable than Ga. Also, X-ray diffraction measurement revealed that single crystals of (400) and (200) were formed at the both sub-strate temperatures of 52$0^{\circ}C$ and 54$0^{\circ}C$.TEX>.

• Journal of the Semiconductor & Display Technology
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• v.17 no.4
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• pp.27-31
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• 2018

The effect of $NH_3$ plasma passivation on the chemical and electrical characteristics of ALD HfAlO dielectric on the InGaAs substrate was investigated. The results show that $NH_3$ plasma passivation exhibit better electrical & chemical performance such as much lower leakage current, lower density of interface trap(Dit) level, and low unstable interfacial oxide. $NH_3$ plasma passivation can effectively enhance interfacial characteristics. Therefore $NH_3$ plasma passivation improved the HfAlO dielectric performance on the InGaAs substrate.

• JSTS:Journal of Semiconductor Technology and Science
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• v.1 no.2
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• pp.111-115
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• 2001

Metamorphic InAlAs/InGaAs HEMT are successfully demonstrated, exhibiting several advantages over conventional P-HEMT on GaAs and LM-HEMT on InP substrate. The strain-relaxed metamorphic structure is grown by MBE on the GaAs substrate with the inverse-step graded InAlAs metamorphic buffer. The device with 40% indium content shows the better characteristics than the device with 53% indium content. The fabricated metamorphic HEMT with $0.2\mu\textrm{m}$T-gate and 40% indium content shows the excellent DC and microwave characteristics of $V_{th}-0.65V,{\;}g_{m,max}=620{\;}mS/mm,{\;}f_T120GHZ{\;}and{\;}f_{max}=210GHZ$.