Method for preparing AlN crystal through spontaneous nucleation by PVT method

Abstract

The invention relates to a method for preparing AlN crystal through spontaneous nucleation by a PVT method. The method comprises the following steps: 1) purifying AlN powder; and 2) putting the purified AlN powder into a crucible (1), putting a metal wire mesh (2) at a position which is 1 / 5-4 / 5 of the height of the interior of the crucible (1), enabling the AlN powder to be located below the metal wire mesh (2), then putting the crucible (1) into a graphite heating body, putting the graphite heating body into a single crystal growth furnace, vacuumizing the single crystal growth furnace to 10E-6mbar at normal temperature, and then under a pure nitrogen atmosphere of 100-1000mbar, conducting heating to 2000-2300 DEG C at the heating rate of 100-150 DEG C / h, keeping the temperature for 24-72 hours, and then conducting cooling to room temperature at the cooling rate of 100-150 DEG C / h, so as to grow AlN crystals on the surface of the metal wire mesh (2) in a spontaneous nucleation manner. The prepared AlN crystal is high in crystal grain quality and large in size.

Description

technical field [0001] The invention belongs to the technical field of semiconductor material preparation, and relates to a method for preparing AlN crystals, in particular to a method for preparing AlN crystals by spontaneous nucleation by a PVT method. Background technique [0002] Aluminum nitride (AlN) has become one of the ideal materials for manufacturing high-efficiency and high-power devices due to its wide direct band gap (up to 6.2eV) and high thermal conductivity (up to 330W / m·K). [0003] Studies have shown that the PVT (Physical Vapor Transport) method is one of the most effective methods for preparing large-volume AlN single crystals. Compared with other techniques (such as hydride vapor phase epitaxy or metal organic vapor phase epitaxy), the AlN crystal grown by PVT method has higher crystal integrity and growth rate. [0004] However, the current traditional PVT method for preparing AlN crystals mostly prepares AlN crystals by crystallization growth on the ...

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Problems solved by technology

[0006] In order to overcome the defects of the prior art, the present invention proposes a method for preparing AlN crystals by spontaneous nucleation by the PVT method, which can solve the problem of the large nucleation density of the crucible top cover that exists in the process of preparing AlN crystals by spontaneous nucleation by the PVT method. This leads to the problem of poor crystal quality and small size

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