The present invention has an objective to provide a high performance
piezoelectric element in which is formed an aluminum nitride thin film
free from hillocks, cracks, and peeling which exhibits superhigh c-axis
orientation, by forming a bottom electrode from a W layer with no
intervening adhesive layer on a glass or other cheap substrate. The
piezoelectric element of the present invention is a piezoelectric element
using a superhigh-oriented aluminum nitride thin film characterized in
that the piezoelectric element is free from hillocks, cracks, and peeling
and includes a stack structure in which a bottom electrode, a
piezoelectric body thin film, and a top electrode are sequentially formed
on a substrate; the bottom electrode is made of an oriented W layer of
which a (111) plane of W is parallel to a surface of the substrate; and
the piezoelectric body thin film is formed of a c-axis-oriented aluminum
nitride thin film having a rocking curve full width half maximum (RCFWHM)
not exceeding 2.5.degree..