Crystallographic Dependency of β-Ga₂O₃ Nitridation via RF Nitrogen Plasma for GaN Heteroepitaxy

RF-plasma assisted nitridation was used to transform (100) β-Ga2O3 to (0001) wurtzite GaN and subsequently grow a 520 nm p-GaN cap layer over 5 intervals. The final step involved a 11.5 hour anneal at the growth temperature of 680 qC to allow for equilibration inside the crystal body. The nitridated film was characterized via X-ray diffraction (XRD), which revealed peaks distinct from the (0001) family. Analysis of these distinct peaks revealed varying (h0l) orientations. We theorize that the alternate orientations are forming to accommodate the growing GaN film, gradually shifting towards the ideal heteroepitaxy plane of (201). XRD rocking curves of the (0002) GaN were used to analyze crystallinity as a function of thickness. Results showed a transformation at the 120 nm interval, from a single Gaussian-like peak to a broad-narrow dual peak configuration. The FWHM's were extracted and plotted against a previous study, indicating narrower, improved peak of 20%.