Single Crystal manufacturing method
View Patent ↗Single crystalline ingots can be stably pulled free from dislocation and with a good crystal shape by actuating a crystal driving unit so as to immerse a seed crystal in a silicon melt, and controlling the crystal driving unit and a crucible driving unit under predetermined conditions so as to pull the seed crystal. During pulling, a horizontal magnetic field positioning device applies a magnetic field in the horizontal direction to the inside of the silicon melt, fixing the magnetic field axis at a constant position from the liquid surface of the melt. Positional adjustment of the vertical position of the horizontal magnetic field is performed in advance by a magnetic field position adjusting device, and the magnetic field axis of the applied field is fixed at a constant distance lower than the liquid surface of the melt by more than 50 mm and at the same level or higher than a depth L from the melt surface at the point of tail-in.
1. A method for manufacturing a single crystal ingot by the Czochralski process from a raw material melt contained in a crucible within a pulling chamber, the raw material melt having a melt surface, comprising:
applying to the raw material melt, a horizontal magnetic field having a magnetic field axis, the magnetic field axis positioned at >50 mm and ≦90 mm below the melt surface;
pulling a single crystal from the raw material melt while maintaining the position of the melt surface constant by controlling a vertical position of the crucible;
maintaining the magnetic field axis at a constant distance H from the melt surface and equal to or less than a depth L from the melt surface of the raw material melt remaining in the crucible on completion of pulling of a constant diameter portion of the single crystal.
2. The method of claim 1 , wherein the position of the magnetic field axis is set between 60 mm to 90 mm below the melt surface.
3. The method of claim 1 , wherein the position of the magnetic field axis is set at a position between 70 mm to 90 mm below the melt surface.
4. The method of claim 1 , wherein the position of the magnetic field axis is set at a position between 60 mm to 70 mm below the melt surface.