Preparation method of low-stress silicon carbide single crystal and apparatus of same

Abstract

The invention belongs to the technical field of crystal growth and particularly relates to a preparation method of a low-stress silicon carbide single crystal and an apparatus of same. In the invention, crystal stress during the growth process is reduced by changing the shape of a heat preservation layer II on a graphite crucible and changing the temperature gradient in a growth thermal field; meanwhile, the method further includes in-situ annealing in a growth chamber after the growth is finished, and further reduction of internal stress of the crystal after the crystal growth is finished. Inthe method, by optimizing the temperature field, the source which introduces the internal stress of the crystal during the growth process is eliminated, thereby producing the low-stress silicon carbide single crystal, and reducing crystal cracking rate during the process and improving mechanical property of the substrate. In addition, by means of the in-situ high-temperature annealing continuousto the growth process, residual internal stress of the crystal is continuously reduced, annealing time being short and efficiency being high. In subsequent process, a long-time high-temperature annealing for stress removal is unnecessary, so that production efficiency is increased and production cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of crystal growth, and in particular relates to a method for preparing a low-stress silicon carbide single crystal and a device thereof. Background technique [0002] Silicon carbide single crystal is one of the most important third-generation semiconductor materials. It is widely used in power electronics, RF devices, optoelectronic devices and other fields. The current mainstream silicon carbide single crystal growth technology is the physical vapor transport (PVT) method, that is, the gas phase source generated by the sublimation of silicon carbide raw materials is transported to the seed crystal at high temperature for recrystallization. When growing silicon carbide single crystal by PVT method, due to the large radial temperature gradient in the growth chamber, there is a large internal stress in the grown silicon carbide single crystal, and the problem of internal stress increases with the increase of...

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Problems solved by technology

However, there is also the problem of radial temperature gradient in the annealing furnace, so it can only slow down the internal stress to a small extent or even have no effect on the internal stress relief in the crystal

In addition, the usual high-temperature annealing method needs to last for several days or even dozens of days at a high temperature of 1000-2000 ° C, resulting in high energy costs, long cycle times, and poor efficiency.

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