To provide a method for producing granular silicon crystals, by which high quality granular silicon crystals having excellent conversion efficiency characteristics are stably manufactured and low-cost granular silicon crystals having excellent mass-productivity are produced.
Granular silicon crystals are produced by heating silicon granules in an argon gas atmosphere containing reactive gases of an oxygen gas and a nitrogen gas so as to form a silicon oxynitride film on the surfaces of the silicon granules and to melt the silicon inside the film and thereafter by lowering the temperature to solidify and crystallize the silicon granules. In the above production, the silicon granules are thermally annealed, after melted and solidified, at a temperature of 1,000-1,380°C for 0.5-24 hours in an atmospheric gas having ≤25% oxygen partial pressure.
KITAHARA NOBUYUKI
ARIMUNE HISAO
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