• 전기의세계
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• v.28 no.9
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• pp.60-73
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• 1979

이 논문은 1979년 vol. 28 n. 4에 이어지는 글이다.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.48-49
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• 2001

GaN는 wurzite structure를 갖는 wide bandgap III-V족 반도체로서, 청색 반도체 laser diode (LD), light emitting diode (LED)등으로 응용되는 물질이다. InGaN quantum well은 GaN계의 청색 LD, LED 구조에서 활성층으로 사용되기 때문에 이에 대한 광학적 연구가 활발하다. InGaN는 GaN위에 성장하면 strain에 의해 piezoelectric 효과가 크게 나타나는 것으로 알려져 있다. 이러한 piezoelectric potential에 의해 외부에서 voltage가 가해지지 않은 상황에서도 InGaN quantum well내의 electron, hole의 wave function이 비대칭 potential의 영향을 받게된다. (중략)

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.17.1-17.1
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• 2011

Inorganic III-V light emitting diodes (LEDs) have superior characteristics, such as long-term stability, high efficiency, and strong brightness compared to conventional incandescent lamps and OLED. However, due to the brittle property of bulk inorganic semiconductor materials, III-V LED limits its applications in the field of high performance flexible electronics. This seminar introduces the first flexible and implantable GaN LED on plastic substrates that is transferred from bulk GaN on Si substrates. The superb properties of the flexible GaN thin film in terms of its wide band gap and high efficiency enable the dramatic extension of not only consumer electronic applications but also the biosensing scale. The flexible white LEDs are demonstrated for the feasibility of using a white light source for future flexible BLU devices. Finally a water-resist and a biocompatible PTFE-coated flexible LED biosensor can detect PSA at a detection limit of 1 ng/mL. These results show that the nitride-based flexible LED can be used as a type of implantable LED biosensor and as a therapy tool.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.353-355
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• 1988

The properites of Zn-diffusion in III-V ternary alloy semiconductor $In_{1-x}Ga_{x}p$, which was grown by the temperature gradient solution (TGS) method, have been investigated. The composition, x, dependence of the Zn-diffusion coefficient at $850^{\circ}C$ and the activation energy for Zn-diffusion into $In_{1-x}Ga_{x}p$ were found to be $D850^{\circ}C$(x)= $3.935{\times}10^{-8}exp(-6.84{\cdot}x)$, and $E_{A}(x)=1,28+2,38{\cdot}x$, respectively. From this study, we confirm that the Zn-diffusion in $In_{1-x}Ga_{x}p$ was explainable with the diffusion mechanisms of the interstitial-substitutional, which was widely accepted mechanisms in the III-V binary semiconductors.

• Korean Journal of Materials Research
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• v.9 no.6
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• pp.599-603
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• 1999

We have investigated the growth characteristics of thick GaN on Sim substrate with AlN and low temperature GaN buffer layer. The vertical hydride vapor phase epitaxy system with $GaCl_3$ precursor was used for growth of GaN. AlN and GaN buffer layer were deposited on Si substrate to reduce the lattice mismatch and the thermal expansion coefficient mismatch between si and GaN. Optimization of deposition condition for AlN and low temperature GaN buffer layers were carried out. We studied the effects of growth temperature, V/III ratio on the properties of thick GaN. Surface morphology, growth rate and crystallinity of thick GaN were measured using Atomic Force Microscopy (AFM), $\alpha-step$-, Scanning Electron Microscopy (SEM) and X-Ray Diffractometer(XRD).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12S
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• pp.1187-1194
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• 2003

A BCl$_3$/Ne plasma chemistry was used to etch Ga-based (GaAs, AIGaAs, GaSb) and In-based (InGaP, InP, InAs and InGaAsP) compound semiconductors in a Planar Inductively Coupled Plasma (ICP) reactor. The addition of the Ne instead of Ar can minimize electrical and optical damage during dry etching of III-V semiconductors due to its light mass compared to that of Ar All of the materials exhibited a maximum etch rate at BCl$_3$ to Ne ratios of 0.25-0.5. Under all conditions, the Ga-based materials etched at significantly higher rates than the In-based materials, due to relatively high volatilities of their trichloride etch products (boiling point CaCl$_3$ : 201 $^{\circ}C$, AsCl$_3$ : 130 $^{\circ}C$, PCl$_3$: 76 $^{\circ}C$) compared to InCl$_3$ (boiling point : 600 $^{\circ}C$). We obtained low root-mean-square(RMS) roughness of the etched sulfate of both AIGaAs and GaAs, which is quite comparable to the unetched control samples. Excellent etch anisotropy ( > 85$^{\circ}$) of the GaAs and AIGaAs in our PICP BCl$_3$/Ne etching relies on some degree of sidewall passivation by redeposition of etch products and photoresist from the mask. However, the surfaces of In-based materials are somewhat degraded during the BCl$_3$/Ne etching due to the low volatility of InCl$_{x}$./.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.47-49
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• 1995

We report the spectroscopic properties of column-III nitrifies of GaN, GaInN, and AlGaN. The column-III nitride semiconductors are promising materials to realize the current-injection-type blue-and ultraviolet (UV)-light-emitting devices with high performance. To acheive the lasing with low threshold, the devices are must constructed to double heterostructure by succesive epitaxial growth technique, and we must confine the carriers in the potential barrier and optical confinement in wave guide between barrier and active layers has different refractive index. The refractive index of column-III nitride semiconductors, however, are rarely reported. The measured refractive index was 2.9, and the observed characteristic peak near the enrgy gap was analysed using a dielectric function and may due to excitonic contribution.

• Journal of the Korean institute of surface engineering
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• v.23 no.4
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• pp.197-207
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• 1990

Atomic layer epitaxy is a relatively new epitaxial pprocess chracterized by the alternate and separate exposure of a susbstrate surface to the reactants contaning the constituent element of a compound semicoductror. The ideal ALE is expected to provide sevral advantageous as petcts for growing complicated heterostrutures such as relativly easy controls of the layer thinkness down to a monolayer and in forming abrupt heterointerfaces though monolayer self-saturatio of the growth. In addition, since ALE is stongly dependent on the surface reaction, the growth can also be controlled by photo-excitation which provides activation can be energies for each step of the reaction paths. The local growth acceleration by photo-excitation can be exploited for growing several device strures on the same wafer, which provides another important practical advantage. The ALE growth of GaAs has advanced to the point the laser opertion has been achieved from AlGs/GaAs quantun well structures where thee active layers were grown by thermal and Ar-laser assisted ALE. The status of the ALE growth of GaAs and other III-V compounds will be reviewed with respect to the growth saturation behavior and the electrical properties of the grown crystals.

• Clinical and Experimental Pediatrics
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• v.45 no.7
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• pp.828-835
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• 2002

Purpose : The outcomes of infants weighing less than 1,500 gm(very low birth weight infant : VLBWI) reflect recent progress in neonatal intensive care. In this study, we analyzed changes over time in survival rate and morbidity of VLBWIs during the past seven years. Methods : A retrospective review of medical records was analyzed for VLBWIs admitted to the neonatal intensive care unit of Samsung Medical Center within three days from birth. We compared the outcomes of previous corresponding data(period I : Oct. 1994 to Sept. 1996), with the outcomes of period II(Oct. 1996 to Dec. 1998) and period III(Jan. 1999 to Dec. 2000). Results : As shown in Tables 1 and 3, the distribution of birth weight, gestational age(GA), gender, and inborn admissions did not change during the 7-year study. The overall survival rate of VLBWI increased significantly over time(period I : 72% vs period III : 88.3%, P<0.05). Between period I and period II, the birth weight-specific survival rate increased by 23.6%(75% vs 92.7%, P<0.05) for infants 1,000 to 1,249 gm. Between period II and period III, the birth weight-specific survival rate increased three times(20% vs 66.7%, P<0.05) for infants <750 gm. The survivors of lowest birth weight included infants at 624 gm(GA : $26^{+5}$ weeks), 667 gm(GA : $25^{+6}$ weeks) and 480 gm(GA : $26^{+2}$ weeks) in each period. The gestational age-specific survival rate in period III increased significantly in GA 25-26 weeks and 29-30 weeks(vs period I & period II, P<0.05). The survivors of lowest gestational age included infants at GA 26 weeks(970 gm), GA $23^{+5}$ weeks(791 gm) and GA $24^{+1}$ weeks(740 gm) in each period. The incidence of severe IVH(grade III, IV) and the early death rate(< seven days) decreased in period III(vs period I; P<0.05), reflecting improvements in neonatal intensive care. Conclusion : The survival rate of VLBWI continues to increase, particularly for BW < 750 gm, GA < 26 weeks. This increase in survival is not associated by any increase in major morbidities.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.3
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• pp.153-163
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• 1986

GaAs, one of the III-V compounding semicondnctors, has been widely employed as base materials for the fabrication of the ultra-high-speed devices in the filelds of DBS, optical communications, MMIC'S and digital IC'S. There have been some reports on 4Kx4bit SRAM by D/E MESFET'S, 4K bit SRAM by HEMT'S, and receiver front ends for X-band by MMIC technologies, respectively. This paper reviews GaAs materials, wafer fabrication processes, device applications, and design aspects, and, finally, descusses the future of the ultra-high-spped-devices.