| The effects of cooling rate of heater, melt weight, seed direction, base materials of crucible and purity of silicon were investigated in the experiment of the silicon single-crystal(diameter 7㎝) growth by Heat Exchanger Method in this paper. Silicon single-crystal which purity was electronic-grade could be grown at the cooling rate lower than 0.8℃/min when the seed with $lt;100$gt; direction was used and twins in parallel with the radial direction were formed at the cooling rate higher than 0.2℃/min when the seed with $lt;111$gt; direction was used. But, in any case, some polycrystal formation at the low edge part of the crystal could not been avoided. When the alumina with low thermal conductivity instead of graphite with high thermal conductivity was used as the base material of crucible, the trend of the poly-crystal formation at the low edge part of the crystal could be diminished. Especially, Silicon single-crystal which purity was metallurgical-grade could be grown at the cooling rate lower than 0.2℃/min when the seed with $lt;100$gt; direction was used. |
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