Freestanding Highly Crystalline Single Crystal AIN Substrates Grown by a Novel Closed Sublimation Method

摘要

We fabricated thick freestanding AIN films by a novel close-spaced sublimation method. The spacing between a sintered AIN polycrystal and a SiC substrate is 1 mm. A Ta ring was used to control the spacing between the AIN polycrystal and the SiC substrate. In addition, a special AIN adhesive was also used to fill in the gap between the AIN polycrystal, the Ta ring, and the SiC substrate. By a combination of these techniques, an AIN growth rate as high as 600 μm/h was achieved. A freestanding AIN layer was obtained by the sublimation of the SiC substrate during the AIN growth.