The effects of film surface roughness on x-ray diffraction of nonpolar gallium nitride films
Moram, M A and Johnston, C F and Kappers, M J and Humphreys, C J
Differences in film surface morphology are found to relate to differences in x-ray diffraction data from nonpolar GaN films. Local strain relaxation at an irregular surface can produce lattice plane bending, leading to surface-specific ω-scan broadening and hence abnormally broad peak widths from reflections associated with shallow x-ray penetration depths. Effects related to surface roughness also contribute to the observed rotational ω-scan width anisotropy. Williamson–Hall plots can be used to estimate to what degree surface roughness effects contribute to the overall ω-scan broadening.
Department of Materials
Imperial College London
Royal School of Mines
London, SW7 2AZ - UK