Rapid ending method for Czochralski silicon

Abstract

The invention discloses a rapid ending method for Czochralski silicon. The rapid ending method for Czochralski silicon comprises the following steps: in an early stage, stopping rising of a crucible,increasing the temperature of a thermal field, maintaining a crystal growth speed, a crystal rotation speed and a crucible rotation speed unchanged, and allowing a crystal diameter to decrease; in a middle stage, reducing the crystal growth speed, driving the crucible to rise, then reducing heating power, increasing the crystal rotation speed and the crucible rotation speed, and allowing the risetrend of the temperature of the thermal field to slow down; and in a later stage, stopping rising of the crucible, maintaining the crystal rotation speed and the crucible rotation speed unchanged, increasing the crystal growth speed, and lifting crystal out of the liquid level of molten silicon when the crystal diameter decreases to 25 to 30 mm so as to complete ending. The rapid ending method forCzochralski silicon can rapidly decrease the crystal diameter on the premise of maintaining the growth speed of monocrystal silicon crystals unchanged; then the method reduces the crystal growth speed, increases the crystal rotation speed and the crucible rotation speed, and decreases heating power to slow down the temperature rising trend of the thermal field, so the tail part of a crystal is prevented from break-off; and finally, a crystal pulling speed is rapidly increased to complete ending, so ending time is greatly shortened, and yield is substantially increased.

Description

technical field [0001] The invention belongs to the technical field of monocrystalline silicon production, and in particular relates to a fast finishing method for Czochralski monocrystalline silicon. Background technique [0002] When using the Czochralski method to pull single crystal silicon, the finishing process can reduce the diameter of the single crystal silicon crystal, so that the effect surface of the thermal stress on the tail of the crystal is reduced, and prevent the dislocation caused by thermal stress when the crystal is lifted out of the molten silicon liquid level produce. [0003] In the traditional finishing process, at the end of crystal growth, it is necessary to gradually increase the temperature of the thermal field, and at the same time reduce the crystal growth rate to reduce the crystal diameter. When the diameter of the end is reduced to less than 5mm (the length reaches 180-210mm), it can be directly cut off. The whole end process takes 3h-3.5h,...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a fast finishing method for Czochralski monocrystalline silicon, which solves the shortcomings of the existing Czochralski monocrystalline silicon finishing process, such as long time and heavy tail weight of single crystal silicon rods.