Single crystal manufacturing method and device

Abstract

The invention provides a single crystal manufacturing method and device. The single crystal manufacturing method using the floating zone method comprises a welding process: heating the front end part of a raw material rod and melting the front end part of a raw material rod, and welding the front end part of a raw material rod to a seed crystal of a crystal conveying mechanism; a reducing process, reducing the diameter of the single crystal in the mode for realizing non-mal-position; a cone part forming process: expanding the diameter and enabling the single crystal to grow; and a straight body part forming process: enabling the single crystal to grow with maintained diameter. The reducing process includes: a diameter reducing control process: operating the current supplied to an induction heating coil and performing PID control for the reduced diameter of the single crystal; and a reducing position control process: operating the descent rate of the single crystal so as to perform PID control for the reducing position of the single crystal. Therefore, the reducing process automation can be realized and the mal-location generation frequency of the single crystal can be reduced after transferring to the cone part forming process.

Description

technical field [0001] The present invention relates to a single crystal manufacturing method and manufacturing apparatus, and particularly relates to single crystal diameter reduction (twisting) control in a floating zone melting method (floating zone silicon refining method, FZ method). Background technique [0002] The FZ method is known as one of methods for growing a single crystal of silicon or the like. In the FZ method, a part of a polycrystalline raw material rod is heated to form a molten zone, and the single crystal is gradually grown by gradually pulling down the raw material rod and the single crystal located above and below the molten zone. In particular, in the initial stage of single crystal growth, after melting the front end of the raw material rod to weld the melted portion to the seed crystal, the single crystal is grown to a certain level while reducing the diameter to a smaller diameter in order to avoid dislocation. The diameter reduction process up t...

AI Technical Summary

Problems solved by technology

Operators operate based on their experience and feeling, but because they directly observe the reducing diameter with their eyes, the judgment of the appropriate state and the amount of operation vary among operators, even if the same operator judges each batch also different

Therefore, the diameter reduction process cannot be performed stably for each batch, and the frequency of occurrence of dislocations in the single crystal after the growth process transferred to the taper part cannot be reduced.

Images