Journal of the Korean Crystal Growth and Crystal Technology (한국결정성장학회지)

The Korea Association of Crystal Growth (한국결정성장학회)
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Growth of GaAs Crystal by an Improved VGF Apparatus

  • Chul-Won Han (Semiconductor Materials Lab. Korea Institute of Science & Technology) ;
  • Kwang-Bo Shim (Semiconductor Materials Lab. Korea Institute of Science & Technology) ;
  • Young-Ju Park (Semiconductor Materials Lab. Korea Institute of Science & Technology) ;
  • Seung-Chul Park (Semiconductor Materials Lab. Korea Institute of Science & Technology) ;
  • Suk-Ki Min (Semiconductor Materials Lab. Korea Institute of Science & Technology)
  • Published : 1991.02.01
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Abstract

The construction details of VGF apparatus with a DM(direct monitoring) furnace for the growth of low defect crystal and characteristics of GaAs crystal grown by this apparatus are described. The average dislocation densities and EL2 concentration of as-grown undoped GaAs along the different solidified fractions exhibit $4{\times}10^{2}-7{\times}10^{3}cm^{-2}$ and $6{\times}10^{14}-4{\times}10^{15}cm^{-3}$, which are less than those observed for liquid encapsulated Czochralski(LEC) or high-pressure vertical gradient freeze(VGF) crystals. These remarkable reduction of the dislocation densities and EL2 concentrations were explained by the lower temperature gradient ($dT/dx-10^{\circ}/cm$) and slower rates of post - growth cooling ($20^{\circ}C/hr:1240-1000^{\circ}C,\;30^{\circ}C/hr:1000-700^{\circ}C$). Also, The Hall mobilities, carrier concentrations show uniform distribution throughtout 80% of the ingot length.

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