| 摘要 |
PURPOSE:To reduce the number of surface defects in a grown layer, by orientating a V-group element evaporating crucible and a III-group element evaporating crucible so that any molecular beam from the former crucible which is reflected by a substrate crystal will not be incident upon the latter crucible. CONSTITUTION:A crucible for an As material 11 and a crucible for a Ga material 13 are oriented with respect to a substrate 14 so that, even if an As molecular beam 12 emitted from the former crucible is reflected by the substrate 14, it will not enter the latter crucible. In other words, the crucibles 11 and 13 are disposed so that the molecular beam 12 reflected and scattered by the substrate 14 mainly travels in a direction in which it will not intersect the Ga source 13. In addition, it is effective to dispose the crucible 11 so that the molecular beam 12 reflected by the substrate 14 is completely trapped by a shroud 16 cooled by liquid nitrogen.
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