Annealing treatment method and device for reducing internal stress of crystal

Abstract

The invention provides an annealing treatment method for reducing the internal stress of a crystal. The annealing treatment method comprises the following steps: (1) a preparation stage: putting the crystal to be annealed into a crucible, vacuumizing the crucible, and introducing inert gas; and (2) a heating stage: heating the crucible by using a heating device, and in the heating process, respectively controlling the heating temperatures of a plurality of first heating rings concentrically arranged above the crucible in the heating device so that the crucible forms a radial temperature gradient. The heating temperature of a plurality of first heating rings of the heating device is controlled, the crucible forms the radial temperature gradient, the radial temperature gradient different from or opposite to the radial temperature gradient during crystal growth can be obtained and radial stress of the crystal can be remarkably reduced. The heating temperature of the first heating ring below the crucible and the heating temperature of the third heating ring on the side face of the crucible are controlled, the axial temperature gradient of the crucible is achieved, the axial temperaturegradient different from or opposite to the axial temperature gradient of the crystal in the growth process can be obtained and basic elimination of residual thermal stress can be achieved.

Description

technical field [0001] The invention relates to an annealing treatment method and device for reducing internal stress of crystals, and belongs to the technical field of annealing treatment after crystal growth is completed. Background technique [0002] Silicon carbide is one of the third-generation wide-bandgap semiconductor materials after silicon and gallium arsenide. Widely used in power electronics, radio frequency devices, optoelectronic devices and other fields. High-quality crystals are the cornerstone of the development of semiconductor and information industries, and their preparation level restricts the preparation and performance of downstream devices. Although physical meteorological transport (PVT) growth of silicon carbide crystals has made great progress in recent years, for large-size single-crystal silicon carbide, excessive residual stress is an urgent problem to be solved, especially for ≥6-inch If the silicon carbide single crystal is too high, too muc...

AI Technical Summary

Problems solved by technology

The number of top heaters is 1 or 2, and the power of the appropriate top heater is set to make the temperature at the center of the crystal higher than the temperature at the edge, or to make the temperature at the top of the crystal higher than the temperature at the bottom, but the radial temperature gradient of the crystal cannot be changed or eliminated , the intelligent control of the temperature gradient cannot be realized, and the stress inside the crystal cannot be completely eliminated, and the device is used for in-situ annealing of the crystal, which will reduce the productivity of the crystal growth furnace

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