Homoepitaxial growth of 3-inch single crystalline AlN boules by the physical vapor transport process

Single crystalline aluminum nitride (sc-AlN or AlN) boules with a diameter of 3-inch (phi 76 mm) were successfully prepared by the physical vapor transport (PVT) process. The initial homoepitaxial growth run was performed on an aluminum nitride seed sliced from a phi 51 mm aluminum nitride boule, and diameter enlargement was conducted iteratively via the lateral expansion technique until a phi 76 mm boule was achieved. During the diameter expansion growth runs, the crystal shape transitioned from a hexagonal pyramid to a cylindrical pyramid. After the standard slicing and wafering processes, the as-obtained substrates were characterized by high-resolution X-ray diffraction (HRXRD), preferential chemical etching, and optical spectroscopy. The characterization results revealed that the aluminum nitride substrates showed good crystallinity and excellent UV transparency, although a slight quality deterioration was observed when the crystal size was expanded from phi 51 to phi 76 mm, while the deep-UV (DUV) transparency remained very similar to that of the aluminum nitride seeds. The phi 76 mm aluminum nitride boules obtained in this study are an important milestone towards achieving phi 100 mm (4-inch) aluminum nitride, which are essential for the rapid commercialization of deep-UV optoelectronics and ultra-wide bandgap (UWBG) electronics.

Automated summary

Single crystalline aluminum nitride (sc-AlN or AlN) boules with a diameter of 3-inch (phi 76 mm) were successfully prepared via the physical vapor transport (PVT) process. The crystal shape transitioned from a hexagonal pyramid to a cylindrical pyramid during the diameter enlargement. The aluminum nitride substrates showed good crystallinity and excellent UV transparency, making them important for the commercialization of deep-UV optoelectronics and ultra-wide bandgap (UWBG) electronics.