ALUMINUM NITRIDE THIN FILM-METALLIC ELECTRODE STACK, AND THIN FILM PIEZOELECTRIC RESONATOR USING IT

摘要

PROBLEM TO BE SOLVED: To provide a thin film piezoelectric resonator which is large in electric-mechanic coupling factor and is excellent in acoustic quality coefficient (Q value), band width, and frequency temperature property.;SOLUTION: This resonator is equipped with a piezoelectric stacked structure 14, where a lower electrode 15, a c-axis oriented AlN piezoelectric thin film 16, and an upper electrode 17 are stacked in this order via an insulator layer 13 in a position facing a via hole 20 of a substrate 12. The lower electrode 15 is composed of two or more metallic layers including the lamination layer of the first metallic layer having body-centered cubic structure such as molybdenum, tungsten, or the like, and a second metallic layer having face-centered cubic structure such as iridium, platinum, or gold. The thickness of the first metallic layer is half or over the thickness of the lower electrode 15. The rocking curve half value width (FWHM) of the (110) diffraction peak of the first metallic layer is less than 4.5°, and the rocking curve half value width (FWHM) of the (0002) diffraction peak of an AlN piezoelectric thin film 16 is less than 3.3°.;COPYRIGHT: (C)2003,JPO