A method and reactor for preparing aluminum nitride crystals with multi-source material is proposed. That is, a new type of controllable feeding structure for a plurality of source materials, by changing the structure of a conventional crystal reactor, it is possible to grow at least two kinds of crystals separately without changing the growth conditions to form a multi-layered structure of ABABA... The multi-layered structure allows the thickness of the grown crystal to be controlled within a

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... ange that does not generate excessive stress. Based on the multi-physics simulation software COMSOL Multiphysics, a model was built to simulate the temperature distribution of the crucible structure. The results show that when the crystal grows, the large temperature gradient at the surface of the crystal leads to large shear stress at the edge, which easily causes the crystal to produce defects or cracks. The experimental simulation results of temperature gradient and thermo-shear stress show that the multi-layered crystal structure can effectively reduce the defects caused by the stress, so as to achieve the purpose of improving the crystal quality.