EFECTO DEL TRATAMIENTO TÉRMICO EN MODOS VIBRACIONALES DE PELÍCULAS DELGADAS DE NITRURO DE ALUMINIO

Reactive magnetron sputtering was used to prepare aluminum nitride (AlN) films at an intermediate substrate temperature of 450 oC. In order to analyze the microstructure and vibrational phonon modes of Al x N y and Al m O n clusters, the sample was subjected to thermal annealing in a controlled nitrogen atmosphere at temperatures of 550 oC and 650 oC, for 20 minutes. The morphological surface was studied by scanning electron microscopy (SEM), and allows us to determine the size, geometry and the facets formation of AlN crystals. The change of microstructure from wurtzite-AlN as-prepared cubic-AlN annealing samples is discussed. From Fourier transform infrared spectroscopy (FTIR) measurements in the range of 650 to 2000 cm -1 , the phonon frequencies of Al x N y and Al m O n clusters were obtained. The experimental frequencies were compared to theoretical calculations by using density Functional theory (DFT).