System for pulling-up monocrystal and method of exhausting silicon oxide

A monocrystal pulling system according to the Czochralski technique, comprising:

• a pulling chamber;
• a movable crucible provided inside said pulling chamber having an inner and outer circumference;
• a heating means provided at a circumference of said crucible and for melting a material accommodated in said crucible for forming a monocrystal;
• a heat retention means provided a specific distance away from said heating means and for retaining the heat of the crucible;
• a means for supplying a carrier gas from the top of the pulling chamber toward a surface of a melt solution in said crucible;
• and
• a flow controller made of carbon which guides the carrier gas to the surface of the melt of the material forming the monocrystal and exhausts silicon oxide vaporizing from the surface of the melt solution to the outside of said pulling chamber and which surrounds the said pulled monocrystal near the surface of said melt and is provided partially inside said crucible,
• said flow controller comprises
• a tubular portion which has an outer diameter smaller than an inner diameter of the crucible and extends approximately perpendicularly to the direction of downward flow of the carrier gas,
• a constricted diameter portion which constricts in diameter from a bottom end of the tubular portion and forms a bottom gap with the pulled monocrystal, and
• an engagement portion which projects out from a top of the tubular portion and forms a top gap at the outer circumference of the tubular portion of said flow controller by supporting the flow controller partially in the pulling chamber,
• a first flow path through which said carrier gas flows toward said bottom gap is defined between the inside of said tubular portion and the pulled up monocrystal,
• a second flow path is defined comprised of a flow path of the carrier gas passing through said top gap and a flow path of said carrier gas passing from said first flow path through said bottom gap and then passing between the surface of said silicon melt solution and said flow controller, and
• said silicon oxide is exhausted together with the carrier gas through said second flow path the outside of the pulling chamber.