The invention discloses a high-temperature bonding method for aluminum
nitride seed crystals. The aluminum
nitride seed crystal, a
seed crystal supporting piece and a high-purity aluminum
nitride raw material are placed in a
crucible of a closed structure, the
seed crystal supporting piece and the seed
crystal are placed at the bottom of the
crucible, and the aluminum nitride
raw material is fixed to the position above the seed
crystal; and bonding is completed in a high-temperature furnace. The bonding method mainly comprises the following steps that (1) vacuumizing a high-temperature furnace, introducing high-purity
nitrogen, and increasing the temperature to a certain temperature, wherein the seed
crystal temperature in the process is higher than the
raw material temperature; (2) continuously raising the temperature while the temperature raising speed of the raw material is greater than that of the seed crystal to form a gradient that the temperature of the seed crystal is less than that of the raw material, keeping the temperature after raising the temperature to a set high temperature, thermally bonding the seed crystal and the seed crystal support during the temperature keeping period, and depositing aluminum nitride on the surface of the seed crystal; and (3) finally cooling to
room temperature. The high-temperature bonding method provided by the invention solves the technical problems that the seed crystal is easy to fall off, holes are formed, the seed crystal is polluted by impurities, the growth surface is damaged and the like in the chemical bonding and mechanical fixing methods of the seed crystal.