Electrical and structural comparison of (100) and (002) oriented AlN thin films deposited by RF magnetron sputtering

Aluminium nitride (AlN) thin film is a very attractive material to be used in electronic devices, and the most popular AlN orientations that have been reported are AlN (100) and AlN (002) planes. To the best of our knowledge, still less comparison study between AlN (100) with AlN (002) orientation based on a structural relationship with the electrical properties. For that purpose, the c-axis (002) and a-axis (100) of AlN thin films are deposited by using conventional RF magnetron sputtering. Energy-dispersive spectroscopy (EDS) analysis shows that AlN (100) has a higher percentage of oxygen content than AlN (002). X-ray diffraction (XRD) reveals that (002)-oriented AlN has better crystallinity than (100)-oriented AlN. Besides, from atomic force microscope (AFM) analysis, (100)-oriented AlN shows a smaller grain size (35.97 nm) than that of (002)-oriented AlN (58.47 nm). By impedance analyser, (100)-oriented AlN thin film shows higher electrical conductivity by one order magnitude higher than (002)-oriented AlN thin film due to high dielectric permittivity, high dielectric loss, fast dielectric relaxation, and lower capacitance. Hence, this study has shown a clear comparison between AlN (100) and AlN (002) based on structural and electrical properties relationship.