AlxGa1-xN epitaxial films with different Al component contents were preparated by metal organic chemical vapor deposition (MOCVD) method. Defects and dislocations in epitaxial films were analyzed by TEM. ω/2θ scan of AlxGa1-xN epitaxial films was measured by high resolution X-ray diffraction test. The results show that the epitaxial films are hexagonal wurtzite structure, lattice constants of symmetry and asymmetry planes are calculated by correcting the crystal plane distances and the strain of epitaxial films is analied. The tetragonal distortion of epitaxial films is less than zero and reduces with the Al content increasing, the compressive strain exists in horizontal direction.
