Study on the Performance of GaN Homoepitaxial Films Grown on Polished Substrates by Different Slurries

GaN is considered one of the most promising wide-band-gap semiconductor materials, which has attracted significant attention due to its excellent properties. Here, the performance of the GaN homoepitaxial films grown on different polished substrates by Al2O3 slurry and SiO2 slurry respectively are studied. Atomic force microscope observation shows that the GaN homoepitaxial film grown on polished GaN substrate by the SiO2 slurry could exhibit low-roughness ultra-smooth surface and step-flow growth mode morphology, compared to that grown on the polished GaN substrate by Al2O3 slurry. High-resolution X-ray diffraction, Raman, photoluminescence, and cathodoluminescence measurements are used to investigate the characteristics of the homoepitaxial GaN films on the polished GaN substrates by different slurries. The results indicate that GaN homoepitaxial film grown on the ultra-smooth GaN substrate polished by SiO2 slurry has better crystalline quality, less impurities/defects, lower residual stress, and near stress-free, which has great potential for more advanced devices.