Reduction of threading dislocation density and suppression of cracking in sputter-deposited AlN templates annealed at high temperatures

Combination of sputter deposition and high-temperature annealing is a promising technique for preparing AlN templates with a low threading dislocation density (TDD) at a lower film thickness compared to those prepared by the conventional metalorganic vapor phase epitaxy. However, cracking of AlN films during annealing is a critical issue. In this study, we controlled the residual stress of the sputter-deposited AlN films by modifying the sputtering conditions. Consequently, the occurrence of cracking was effectively suppressed. By optimizing the fabricating conditions, a TDD of 2.07 × 108 cm−2 was achieved for the AlN template with a thickness of 480 nm.