Device and method for controlling radial temperature gradient of silicon carbide monocrystalline growth

Abstract

The invention relates to a device and method for controlling a radial temperature gradient of silicon carbide monocrystalline growth. The device comprises a carbon-fiber cone-shaped air blowing device arranged on a crucible cover, an upper port of the carbon-fiber cone-shaped air blowing device is connected with a carbon-fiber tee joint, one port of the carbon-fiber tee joint is connected with a frequency-conversion circulating air device, another port of the carbon-fiber tee joint is connected with a thermodetector, and the frequency-conversion circulating air device and the thermodetector are both connected with a PLC control system. The method comprises the steps that a technological set temperature is compared with a temperature measured by the thermodetector, and the PLC control system sends a signal to the frequency-conversion circulating air device to adjust the temperature. According to the device and method for controlling the radial temperature gradient of silicon carbide monocrystalline growth, the radial temperature can be changed without changing the radial position, the radial temperature can be adjusted automatically, the temperature is set according to the needs of a grown crystal, the stable radial temperature is maintained, it can be guaranteed that the crystal grows at the optimum temperature all the time, the crystal grows stably, and the crystal quality is improved.

Description

technical field [0001] The invention relates to a large-diameter silicon carbide single crystal growth process, in particular to a process for controlling the radial temperature gradient of silicon carbide single crystal growth. Background technique [0002] At present, the mature silicon carbide single crystal growth products are all below 4 inches. After increasing the diameter size, the quality defects of the grown crystals increase significantly, and it is more difficult to increase the diameter. In the method of high-temperature physical vapor phase generation of silicon carbide single crystal, only the axial temperature gradient is emphasized, so that the silicon carbide single crystal condenses at a low temperature to form silicon carbide crystals under a certain axial temperature gradient. Temperature gradient, as the crystal grows, the radial temperature of the crystal will increase, and the increase in temperature is not suitable for the growth of the crystal, so i...

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Problems solved by technology

In the method of high-temperature physical vapor phase generation of silicon carbide single crystal, only the axial temperature gradient is emphasized, so that the silicon carbide single crystal condenses at a low temperature to form silicon carbide crystals under a certain axial temperature gradient. Temperature gradient, as the crystal grows, the radial temperature of the crystal will increase, and the increase in temperature is not suitable for the growth of the crystal, so it is difficult for the diameter of the crystal to grow larger, even if it grows, but the radial quality is very inconsistent , it is easy to produce dislocations and holes, and it is difficult to control the radial temperature gradient under vacuum and high temperature conditions. The axial temperature gradient can be adjusted by adjusting the position of the crucible or the induction coil, which is relatively easy to achieve, while the radial temperature is due to the crucible There is no way to change the radial position of the crucible and the coil. The center of the crucible and the center of the coil must be at the same position. The temperature around the crucible can be uniform. The growing seed crystal is glued to the crucible cover, and the crucible cover and the crucible are in good agreement. Yes, its radial position cannot be changed like the crucible, so the current high-temperature physical vapor deposition method for growing SiC single crystals cannot adjust the radial gradient of crystal growth

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