Method for pulling a single crystal by the FZ method comprising reducing the power of a melting apparatus based on geometrical dimensions of the drop

A method for pulling a single crystal by the FZ method by melting a polycrystal by means of an electromagnetic melting apparatus and then recrystallizing the polycrystal, comprising:

• in a first phase (P1), moving the polycrystal toward the melting apparatus and melting a lower end of the polycrystal by means of the melting apparatus to form a drop;
• in a second phase (P2), attaching a monocrystalline seed to the drop at a lower end of the polycrystal, and melting the monocrystalline seed beginning from an upper end of the seed;
• predetermining during the first phase (P1) and during the second phase (P2), at least temporarily, a power (P) of the melting apparatus in dependence on a temperature and/or geometrical dimensions (d, h) of crystal material used, which comprises the drop and/or the seed and/or the polycrystal;
• during the first phase (P1), reducing the power (P) of the melting apparatus after attainment of predefined geometrical dimensions (h, d) of the drop at a timepoint (t2), the predefined geometrical dimensions being predetermined on the basis of an equilateral triangle, which fits into a form of the drop, where the lowest point of the drop is used as the vertex of the equilateral triangle and where the phase boundary between liquid and solid material is used as the base of the equilateral triangle.