High-resolution x-ray study of thin GaN film on SiC

The x-ray standing wave method (XSW) and high-resolution x-ray diffraction were used to study the structural perfection and polarity of GaN epitaxial thin film grown by hydride vapor phase epitaxy on the Si-face SiC substrate . The x-ray standing wave was generated inside the 300 nm thin film under t he condition of Bragg diffraction from the film. Excellent crystalline qual ity of the GaN film was revealed by both x-ray techniques. The XSW analysis of the angular dependencies of the Ga-K fluorescence yield measured while scanning through the GaN(0002) diffraction peak unambiguously showed the Ga polarity of the film. Correlation between the mosaic structure and the sta tic Debye-Waller factor of the GaN lattice was also studied. (C) 2001 Ameri can Institute of Physics.