체적 탄성파 공진기의 하부 전극이 압전 박막의 배향성 및 공진기의 압전 특성에 미치는 영향

Abstract

Effects of bottom electrode materials (Al, Cu, Ti, and Mo), included in f ilm bu lk acoustic resonators (FBARs), on the orientation of piezoelectric A IN th in films and the frequency response characteristic of resonators were investigated. The texture coefficient (TC) for (002) orientation, crystallite size, full width half max imum (FWHM ), and surface roughness of deposited A IN films were measured for the various bottom electrodes. The return losses estimated from the frequency responses of fabricated resonators were also compared. Experimental results showed that the difference of lattice constant and thermal expansion coefficient between the bottom electrode and the A IN film were the most important factors for achieving a high performance resonator.