ACOUSTIC WAVE DEVICE

摘要

PURPOSE: An acoustic wave device is provided to use a space efficiently by forming a plurality of piezoelectric membrane resonators sharing one air gap. CONSTITUTION: A sacrificial layer(3) is formed on a substrate(1). A bottom electrode(2) is laminated over the sacrificial layer. A piezoelectric membrane(4) is formed over the substrate in order to cover the sacrificial layer and bottom electrode. Two top electrodes are faced with each other between piezoelectric membranes. One membrane area is suitable for one FBAR. Two membrane areas are formed on the sacrificial layer. A cavity is formed by eliminating the sacrificial layer. Two FBARs are formed in one cavity.