Crystalline structure and surface morphology of AlN films sputtered on rotated Y-cut quartz (ST-quartz)

Highly c-axis-oriented and fine structural AIN films were successfully prep ared on Rotated Y-cut quartz (ST-quartz) by rf magnetron sputtering. The cr ystalline structure of the films was determined by X-ray diffraction (XRD) and the surface microstructure of films was quantitatively investigated usi ng an atomic force microscope (AFM). Different rf powers (250 Mi, 350 W and 350 PV) were used to deposit the films. The films prepared in the rf power range of 250-450 W were all polycrystalline hexagonal AlN and had fine sur face morphology. The experimental results demonstrate that AlN films deposi ted in this research were fine structural piezoelectric films. The optimal AIN films prepared at 250 W had small average grain sizes (13.31 nm), unifo rmity, dense structures and a very smooth top surface (R-a = 1.838 nm). It is suitable to use low power to deposit AlN films on ST-quartz.