PIEZOELECTRIC THIN-FILM RESONATOR AND FILTER USING THE SAME

摘要

A piezoelectric thin-film resonator and a filter using the same are provided to have good property by forming a top electrode or a bottom electrode connected to a membrane, with a fixed shape. A piezoelectric thin-film resonator comprises a hybrid film. According to the hybrid film, a bottom electrode(43) is formed on a substrate(41). A piezoelectric film(44) is formed on the substrate and the bottom electrode. A top electrode(45) is formed on the piezoelectric film. According to a membrane(46) connected to an overlapping region of the top electrode and the bottom electrode, the top electrode and the bottom electrode have equal length along a long axis. In at least one electrode of the top electrode and the bottom electrode connected to the membrane, the shape of the drawing part from the membrane becomes thinner rather than the length along the long axis of the membrane as the shape becomes far from the membrane.