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Kim, Min-Su;Leem, Jae-Young
- Journal of Surface Science and Engineering
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- v.43 no.4
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- pp.176-179
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- 2010
The InAs thin films were grown on GaAs(100) substrate with $2^{\circ}C$ tilted toward [$0\bar{1}\bar{1}$] with different As beam equivalent pressure (BEP) by using molecular beam epitaxy. Growth temperature and thickness of the InAs thin films were $480^{\circ}C$ and 0.5 ${\mu}m$, respectively. We studied the relation between the As BEP and the properties of InAs thin films. The properties of InAs thin films were observed by reflection high-energy electron diffraction (RHEED), optical microscope, and Hall effect. The growth, monitored by RHEED, was produced through an initial 2D (2-dimensional) nucleation mode which was followed by a period of 3D (3-dimensional) island growth mode. Then, the 2D growth recovered after a few minutes and the streak RHEED pattern remained clear till the end of growth. The crystal quality of InAs thin films is dependent strongly on the As BEP. When the As BEP is $3.6{\times}10^{-6}$ Torr, the InAs thin film has a high electron mobility of 10,952 $cm^2/Vs$ at room temperature.
https://doi.org/10.5695/JKISE.2010.43.4.176 인용 PDF KSCI

Choi, Sung-Jai;Lee, Won-Sik
- The Journal of the Institute of Internet, Broadcasting and Communication
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- v.10 no.1
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- pp.7-13
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- 2010
We have investigated effects of the rapid thermal annealing of GaN epilayers by molecular beam epitaxy in nitrogen atmosphere. The improvement of structural properties of the samples was observed after rapid thermal annealing under optimum conditions. This improvement in crystal quality is due to a reduction of the spread in the lattice parameter in epilayers. The annealing has been performed in a rapid thermal annealing furnace at $950^{\circ}C$. The effect of rapid thermal annealing on the structural properties of GaN was studied by x-ray diffraction. The Bragg peak shifts toward larger angle as the annealing time increases. As the thermal treatment time increases, FWHM(full width at half maximum) of the peak slightly increase with its decreases followed and it increases again. Results demonstrate that rapid thermal annealing did not always promote qualities of GaN epilayers. However, rapid thermal annealing under optimum conditions improve structural properties of the samples, elevating their crystal quality with a reduction of inaccuracy in the lattice parameter of the epilayers.
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홍성의;한기평;백문철;조경익;윤순길
- Journal of the Korean Vacuum Society
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- v.10 no.1
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- pp.22-26
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- 2001
Microstructures of AlN thin films on Si substrates grown by plasma assisted molecular beam epitaxy were analyzed with various growth temperatures and substrate orientations. Reflection high energy electron diffraction (RHEED) patterns were checked for the in-situ monitoring of the growth condition. X-ray diffraction(XRD), double crystal X-ray diffraction (DCXD), and transmission electron microscopy/diffraction (TEM/TED) techniques were employed to characterize the microstructure of the films after growth. On Si(100) sub-strates, AlN thin films were grown mostly along the hexagonal c-axis orientation at temperature higher than $850^{\circ}C$. On the other hand the AlN films on Si(111) were epitaxially grown with directional coherencies in AlN(0001)/Si(111), AlN(1100)/Si(110), and AlN(1120)/Si(112). The microstructure of AlN thin films on Si(111) substrates, with a full width at half maximum of almost 3000 arcsec at 2$\theta$=$36.2^{\circ}$, showed that the single crystal films were grown, even if they includ a lot of crystal defects such as dislocations and stacking faults.
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Lee, Jong-Uk
- Journal of the Institute of Electronics Engineers of Korea SD
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- v.41 no.11
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- pp.29-34
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- 2004
This paper reports the RF dispersion and linearity characteristics of unpassivated AlGaN/InGaN/GaN high electron-mobility transistors (HEMTs) grown by molecular beam epitaxy (MBE). The devices with a 0.5 ${\mu}{\textrm}{m}$ gate-length exhibited relatively good DC characteristics with a maximum drain current of 730 mA/mm and a peak g$_{m}$ of 156 mS/mm. Highly linear characteristic was observed by relatively flat DC transconductance (g$_{m}$) and good inter-modulation distortion characteristics, which indicates tight channel carrier confinement of the InGaN channel. Little current collapse in pulse I-V and load-pull measurements was observed at elevated temperatures and a relatively high power density of 1.8 W/mm was obtained at 2 GHz. These results indicate that current collapse related with surface states will not be a power limiting factor for the AlGaN/InGaN HEMTs.
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