• Title/Summary/Keyword: LEC grown SI GaAs

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Quantitative Analysis on Near Band Edge Images in GaAs Wafer (GaAs 웨이퍼의 대역단 영상에 대한 정량적 해석)

  • Kang, Seong-jun;Na, Cheolhun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.5
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    • pp.861-868
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    • 2017
  • Near band infrared imaging technique has adopted for imaging EL2 and shallow level distributions in undoped semi-insulating LEC GaAs. This technique, which relies on the mapping of near bandgap infrared transmission, is both rapid and non-destructive. Until now no quantitative analysis has been reported for near band edge region which gives the reverse contrast on EL2 absorption images. This paper presents the spectral, spatial and temperature dependence of photoquenching forward and inverse mechanism in the band edge domain for cells and walls and for direct and inverted contrast conditions during transitory regimes. The difference in the threshold for the EL2w and EL2b defects could be attributed to the contribution of a different electrical assistance due to a different species of impurities. Quantitative analysis results show an increased density of EL2w and a small reduction of EL2b in the region of the walls where there is a high density of dislocations.

Low-dislocation-density large-diameter GaAs single crystal grown by vertical Bridgman method

  • Kawase, Tomohiro;Tatsumi, Masami;Fujita, Keiichiro
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.6
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    • pp.535-541
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    • 1999
  • Low-dislocation-density large-diameter GaAs single crystals with low-residual-strain have been strongly required. We have developed dislocation-free 3-inch Si doped GaAs crystals for photonic devices, and low-dislocation-density low-residual-strain 4-inch to 6-inch semi-insulating GaAs crystals for electronic devices by Vertical Bridgman(VB) technique. We confirmed that VB substrates with low-residual-strain have higher resistance against slip-line generation during MBE process. VB-GaAs single crystals show uniform radial profile of resistivity reflecting to the flat solid-liquid interface during the crystal growth. Uniformity of micro-resistivity of VB-GaAs substrate is much better than of the LEC-GaAs substrate, which is due to the low-dislocation-density of VB-GaAs single crystals.

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LOW-DISLOCATION-DENSITY LARGE-DIAMETER GaAs SINGLE CRYSTAL GROWN BY VERTICAL BOAT METHOD

  • Kawase, Tomohiro;Tatsumi, Masami;Fujita, Keiichiro
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1999.06a
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    • pp.129-157
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    • 1999
  • Low-dislocation-density large-diameter GaAs single crystals with low-residual-strain have been strongly required. We have developed dislocation-free 3-inch Si-doped GaAs crystals for photonic devices [1], and low-dislocation-density low-residual-strain 4-inch to 6-inch [2, 3] semi-insulating GaAs crystals for electronic devices by Vertical Boat (VB) technique. We confirmed that VB substrates with low-residual-strain have higher resistance against slip-line generation during MBE process. VB-GaAs single crystals show uniform radial profile of resistivity reflecting to the flat solid-liquid interface during the crystal growth. Uniformity of micro-resistivity of VB-GaAs substrate is much better than that of the LEC-GaAs substrate, which is due to the low-dislocation-density of VB-GaAs single crystals.

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Compensation in LPLEC GaAs Single Crystals (LPLEC법으로 성장시킨 GaAs 단결정의 Compensation)

  • Ko, Kyung Hyun
    • Analytical Science and Technology
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    • v.5 no.2
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    • pp.213-216
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    • 1992
  • Semiinsulating GaAs crystals employing LPLEC technique should be grown from the Ga-rich melt due to a very low incorporation of unintentional impurities such as carbon (<$10^{15}cm^{-3}$). High resisitivity of this material can be derived from the balanced compensation among not only EL2 deep donors and carbon acceptors but also H1 double charge native acceptors(Ev + 77meV, Ev + 200 meV) and H2 native acceptors(Ev + 68 meV). Considering of the complicated compensation mechanism using statistical calculation of the electron occupancy of each level, SI GaAs crystal with low impurity contents(<$10^{15}cm^{-3}$) can be successfully obtained by maintaining the melt composition around 0.45 As mole fraction.

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