A control device and method for stabilizing the crystal growth interface of the pulling method

Abstract

The invention belongs to the technical field of crystal growth, and is a control device and method for stabilizing the crystal growth interface of the pulling method; the method includes measuring the weight of crystal growth in real time, and making a difference between the measured crystal weight and its theoretical weight, and according to the difference between the two Use PID control algorithm to control the heating power required for crystal growth; measure the weight of the rod in real time, and use the sum of the measured crystal weight and the weight of the rod as the overall weight, and use PID control according to the difference between the overall weight and its initial weight Algorithm controls the falling speed of the material rod; the CCD optical amplification device is used to rotate the CCD optical amplification device, and the optical amplification device measures the distance corresponding to the gray value of the crystal reference line in real time and the center line of the measurement reference line, according to the difference between the distance and its initial distance The crystal rotation speed is controlled by a PID control algorithm; the invention can maintain the stability of the crystal growth interface and ensure that the crystal shape meets the set size requirements.

Description

technical field [0001] The invention belongs to the technical field of crystal growth, and in particular relates to a control device and method for stabilizing the crystal growth interface of a pulling method. Background technique [0002] A stable crystal growth interface is an important condition for growing high-quality crystals. The current fully automatic single crystal pulling furnace uses a high-precision upper weighing system to indirectly measure the actual growth diameter of the crystal, and feeds back to the computer control system to control the output power of the heating source, which can better control the entire crystal according to the preset shape. Complete the entire growth process. From the beginning of seeding to the end of growth, as the crystal grows, the solid-liquid interface of the crystal moves downward continuously. At different positions, the growth interface is changed by the heat dissipation of the crystal, the heat preservation system changes...

AI Technical Summary

Problems solved by technology

[0004] Based on the problems existing in the prior art, the present invention starts with the factors that cause the shape change of the crystal growth interface, and mainly adopts two methods, one is to continuously add crystal growth raw materials to make the melt interface fluctuate in a very small interval, and solve the problem of Traditional control system due to temperature gradient changes caused by the drop of the melt interface, while facilitating optical detection of crystal diameter deviations

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