Structure and Piezoelectric Properties of Aluminum Nitride Thin Films on Quartz Substrates Deposited by Reactive RF-Magnetron Sputtering

This paper presents the effect of nitrogen concentration (CN) on aluminum-nitride bonding formation, structure and morphology of the aluminum nitride films. The films on the unheated substrates were deposited by radio frequency reactive magnetron sputtering technology using an aluminum target under argon/nitrogen mixture atmosphere. The FTIR and Raman spectra of the films confirmed their absorption bands corresponding to E1 (TO), A1 (TO), and E2 (high) vibration modes of the infrared active aluminum-nitride bonding. The crystallographic orientation of the films was optimized under CN of 40%. The cross-sectional FE-SEM image of the film under this condition showed the columnar structure. The dense columnar grains were uniformly observed on the films surface under all CN, except for CN of 20%. The bulk resistivity and piezoelectric property were investigated via the metal-insulator-metal structures. The results showed that the resistivity was in a range of 1014-1015 Ωcm while the effective piezoelectric coefficient was 11.03 pm/V.