Influence of the Crystal Texture on Raman Spectroscopy of the AlN Films Prepared by Pulse Laser Deposition

We investigate the Raman scattering of the AlN films prepared by pulse laser deposition. The Raman spectrum and the X-ray diffraction (XRD) patterns of the AlN films were compared to find out the influence of the crystal texture on the Raman scattering. The E2 (high) and A1 (TO) scattering modes were observed in Raman spectra. The results show that the orientation and the crystal quality of the AlN films have a great impact on these Raman scattering modes. The deterioration of (002) orientation and the appearance of other orientations in the XRD patterns lead to the weakening of the E2 (high) mode and strengthening of the A1 (TO) mode in the Raman spectrum. In addition, the E2 (high) peak is broadened with the increasing of the width of the X-ray rocking curve. The broadening of the Raman peaks can be associated with degeneration in crystal quality. Furthermore, by combining the energy shift of E2 (high) mode with the measured residual stress in the films, the Raman-stress factor of the AlN films prepared by pulse laser deposition is −4.45 cm−1/GPa for the E2 (high) mode