(Invited) X-Ray Metrology of AlN Single Crystal Substrates

X-ray based techniques were used to characterize AlN single crystal substrates at different stages of production, providing essential information about substrate orientation, surface finish, structural perfection, and heteroepitaxy. X-ray topographs acquired on a commercial diffractometer confirmed that iterative diameter expansion of AlN boules, without the introduction of low angle grain boundaries, was successfully achieved. As a result, high-quality, macrodefect-free, 2-inch AlN substrates were demonstrated.