Ingot puller apparatus that axially position magnetic poles

An ingot puller apparatus for manufacturing a single crystal silicon ingot, the ingot puller apparatus comprising:

• a crucible for holding a silicon melt;
• an ingot puller housing that defines a growth chamber for pulling a silicon ingot from the silicon melt, the crucible being disposed within the growth chamber;
• a pair of magnetic poles disposed radially outward from the crucible;
• a translation device comprising a guide for moving the magnetic poles axially relative to the crucible;
• and
• a controller including a processor and a non-transitory memory storing instructions executed by the processor to configure the controller, the controller configured to cause the translation device to move the pair of magnetic poles to regulate a position of a maximum gauss plane during formation of a constant diameter portion of the silicon ingot in at least two stages of ingot growth, the at least two stages comprising:
• a first stage corresponding to formation of the silicon ingot from a beginning of formation of the constant diameter portion of the silicon ingot up to an intermediate ingot length;
• and
• a second stage corresponding to formation of the silicon ingot from at least the intermediate ingot length to a total ingot length;
• and
• wherein the controller is configured to maintain the position of the maximum gauss plane in the second stage at a position lower than the position of the maximum gauss plane during the first stage, the position of the maximum gauss plane being maintained at a position at least 100 mm below a melt free surface during the second stage.