Growth device for sodium flux method gallium nitride single crystal

Abstract

The invention discloses a growth device for a sodium flux method gallium nitride single crystal. Structures such as a seed crystal clamp, a reaction container and a carrying platform are designed inside the device; in epitaxial growth of a single crystal, the seed crystal can be prevented from contacting a molten metal liquid with an over-saturated nitrogen atom concentration by reducing the height of the carrying platform, so that seed crystal decomposition is avoided, and surface quality degradation is prevented; a reaction cavity tray is driven by a motor connected with a transmission rod to rotate, so that the reaction container and a crucible inside are rotated relative to the seed crystal clamp, the molten metal liquid can be then stirred by a seed crystal clamping rod, the nitrogenatom concentration uniformity inside can be improved, the purpose of increasing the concentration of nitrogen atoms around the seed crystal can be achieved, and crystal nitrogen insufficiency can be avoided; due to adoption of a semi-sealed reaction container structure, escape of sodium steam in the crystal growth process can be reduced, external impurity atmospheres can be baffled, so that the metal sodium can play a role of a fluxing agent continuously, and a stable and pure growth condition can be provided for epitaxy of the gallium nitride single crystal.

Description

technical field [0001] The invention relates to single crystal material growth technology, in particular to a growth device for gallium nitride single crystal by sodium flux method. Background technique [0002] As a third-generation semiconductor material, Gallium Nitride has attracted much attention in the field of optoelectronics and microelectronics due to its excellent characteristics such as wide bandgap, high breakdown voltage and high thermal conductivity. Compared with the rapid development of gallium nitride devices, the growth technology of gallium nitride crystals is relatively lagging behind. The lack of high-quality, large-size gallium nitride substrate materials is an important factor limiting the further improvement of the performance of gallium nitride devices. For the existing GaN single crystal growth method, the hydride vapor phase epitaxy (HVPE) method has the ability to commercially produce large-scale GaN single wafers, but it is limited by the lattice...

AI Technical Summary

Problems solved by technology

Affected by its internal structure design, the conventional crystal growth device has the following problems when using the sodium flux method for gallium nitride crystal growth: First, the seed crystal will directly melt with the metal that has not reached the nitrogen atom supersaturation state in the early stage of crystal growth. Under this condition, the seed crystal will decompose, resulting in the deterioration of the surface quality, and it is difficult to obtain a low-dislocation epitaxial layer; secondly, during the crystal growth process, the metal melt only relies on heat convection for internal flow, and its overall flow rate is relatively slow, making it difficult to obtain an epitaxial layer with low dislocations. Ensure the mixing uniformity of flux metal sodium and raw material gallium metal and the uniformity of nitrogen atom concentration distribution, and it is prone to the phenomenon that the local nitrogen atom concentration is too high, resulting in slow epitaxial growth rate and crystal nitrogen deficiency

Finally, the open crucible connects it with the internal environment of the entire pressure vessel cavity, which will make it difficult to avoid the separation of metal sodium from the crystal growth environment and the introduction of impurity elements at high temperatures, resulting in changes in the composition of the molten metal, resulting in crystal growth characteristics Alteration and Crystal Coloring

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