用于FBAR的C轴取向AlN压电薄膜的研制

用射频（RF）反应磁控溅射法,在硅基片上制备出了具有较低表面粗糙度、C轴择优取向的AlN压电薄膜.讨论了溅射功率对AlN压电薄膜结构和形貌的影响、氮气含量对AlN压电薄膜成分的影响以及低温退火对薄膜表面粗糙度的影响.XRD和SEM结果表明：随溅射功率增大,AlN压电薄膜C轴择优取向增强;当功率为350W时,AlN压电薄膜（002）面摇摆曲线半高宽为4.5°,薄膜表现出明显的柱状结构.EDS成分分析表明：随氮气含量的提高,AlN压电薄膜的元素比接近于化学计量比.低温退火工艺的引入将薄膜表面的均方根粗糙度由4.8nm降低到2.26nm.

Preparation of AlN piezoelectric thin film with C-axis preferred orientation in FBAR application

AlN piezoelectric thin films with low surface roughness and a preferential orientation(002) were deposited on the silicon substrates by RF(radio frequency) magnetron sputtering reaction method.The effects of the sputtering power,nitrogen content and low temperature annealing to the structure,morphology,elemental composition and surface roughness of AlN piezoelectric thin film were discussed.X-ray diffraction and scanning electron microscopy of AlN piezoelectric thin films indicate that the preferred orientation is enhanced with increasing the RF power and the thin film at 350 W RF power shows its obvious columnar structure.The FWHM(full width at half maximum) of(002)rocking curves of AlN piezoelectric thin film obtained at 350 W RF power was 4.5°.The EDS(energy despersive spectrometer) results of AlN piezoelectric thin films demonstrate that the elemental composition of AlN piezoelectric thin film is closed to the stoichiometric ratio with increasing nitrogen content.The low-temperature annealing made surface roughness of the film reduced from 4.8 nm to 2.26 nm.