Low-stress crystal growth method

Abstract

The invention discloses a low-stress crystal growth method, and relates to the field of crystal preparation, in particular to a method for preparing low-stress and low-defect crystals by using a Czochralski method, the method is realized by using a Czochralski method crystal growth device with a movable crystal heating cover, and the crystal growth device comprises a furnace body, a crucible at the bottom of the furnace body, a heating and heat preservation system, a crystal lifting mechanism, and a quartz observation window. The device further comprises a movable crystal heating cover which comprises a heating cover body, heating wires arranged on the periphery of the heating cover body and a heating cover lifting mechanism. In the crystal growth process and after the crystal is pulled out of the melt, the movable crystal heating cover is used for covering. By adopting the method, the temperature gradient in the crystal in the crystal growth process and the cooling process after the crystal is lifted can be reduced, so that the crystal stress is reduced, the defects are reduced, the crystal cracking is avoided, the temperature gradient in the melt is kept, the stability of the crystal growth process is ensured, and the crystal yield is ensured.

Description

technical field [0001] The invention relates to the field of crystal preparation, in particular to a method for preparing low-stress and low-defect crystals by using a pulling method. Background technique [0002] The pulling method is a method of growing crystals from a melt. It is a common growth method for semiconductor crystals and optical crystals. This method has the characteristics of high yield, fast growth speed, and easy observation. [0003] The pulling method is commonly used as a growth method with a single heater. The pulling method is because the crystal is pulled out of the melt, especially when it is pulled to a higher position, the part of the crystal that is pulled out first will be cooled to a lower temperature due to the lower ambient temperature. However, the temperature at the solid-liquid interface of crystal growth is always maintained near the melting point of the crystal. Therefore, assuming that the longitudinal temperature distribution in the cr...

AI Technical Summary

Problems solved by technology

This kind of device uses an external moving coil to heat the crucible and the rear heating cylinder at the same time. There is power interference between the two, and the control accuracy is not high.

Crystal growth requires high temperature stability in the crucible, and the movement of the coil of the heating crucible will have a greater impact on the thermal field. Moreover, the heating cylinder is induced at the same time to shunt the coil power, which is easy to cause melt Temperature gradient fluctuates widely, leading to failure of crystal growth

Moreover, the relative position of the insulation cylinder and the crystal is far away, and the rear heating cylinder will heat the entire environment, which will reduce the entire environment, including the temperature gradient in the melt, and will also cause crystal growth to have low stability.

Moreover, the coil device heats the melt and the crystal during the cooling process at the end of crystal growth, but has no obvious effect on the heat preservation and heating of the crystal during crystal growth.

It has no obvious improvement effect on the stress and dislocation defects caused by the temperature difference between the upper and lower ends of the crystal during the crystal growth process

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