基于掺杂压电薄膜的FBAR制备及研究

Fabrication and Research of FBAR Based on Doped Piezoelectric Film

薄膜体声波谐振器(FBAR)具有体积小、工作频段高、性能强等优势,在滤波器领域有广泛的应用前景,其最核心的功能层为压电薄膜。本文采用磁控溅射方法,在6英寸硅片上制备了AlScN压电薄膜。对AlScN薄膜进行了分析表征,结果表明,AlScN压电薄膜具有良好的(002)面择优取向,摇摆曲线半峰宽为1.75°,膜厚均匀性优于0.6%,薄膜应力为10.63 MPa,薄膜应力可调。制作了基于AlScN压电薄膜的FBAR谐振器,其机电耦合系数为7.53%。在AlN中掺杂Sc能够有效提高压电薄膜的机电耦合系数,对研究FBAR滤波器的宽带化有重要意义。

The film bulk acoustic resonator(FBAR)has the advantages such as small volume,high operating frequency and strong performance,so that it has wide application prospects in the field of filter.The most important functional layer of FBAR filter is the piezoelectric layer composed of piezoelectric materials.In this paper,AlScN piezoelectric films were prepared on 6 inch silicon substrates by magnetron sputtering.The AlScN films were analyzed and characterized.The results show that the preferred orientations for the(002)crystal face of AlScN films are excellent,the full width at half maximum(FWHM)of the rocking curve is 1.75°.The thickness uniformity of AlScN films is less than 0.6%.The film stress is 10.63 MPa,and the stress can be adjusted.FBAR resonators based on AlScN piezoelectric films were prepared.The electromechanical coupling coefficients were 7.53%.The results show that doping Sc in AlN can improve the effective electromechanical coupling coefficient,which is significance for studying the wide band FBAR filter.