Research progress in the postprocessing and application of GaN crystal

Abstract

As a typical representative of the third-generation semiconductor materials, GaN is an ideal substrate for the fabrication of blue-green lasers, RF microwave devices, and power electronic devices. The application of substrate materials cannot be separated from the post-treatment of materials. Although wet etching and thermal annealing are not necessary steps, they have great research value for GaN crystals. This review systematically reviews the importance of wet etching in GaN crystal applications, which can not only characterize the dislocations and study the crystal defects, but can also rapidly remove the damaged layer, improve the grinding and polishing efficiency, and achieve a smooth and non-damaged surface, so as to improve the performance of GaN-based devices. After thermal annealing of the GaN crystal, the surface quality will be improved, stress relaxation will occur, and the photoelectric properties will be significantly improved. Finally, the challenges and opportunities of the wet etching and thermal annealing of GaN crystals are briefly described, and their development prospects are noted.