Columnar structure film and method of forming same, piezoelectric element, liquid ejection apparatus and piezoelectric ultrasonic oscillator

摘要

The columnar structure film is formed on a surface of a substrate by vapor phase epitaxy, and is constituted of a plurality of columnar bodies extending in directions non-parallel to the surface of the substrate. In the columnar structure film, a relationship GS max > 2.0 GS min is satisfied, where GS max and GS min are respectively a maximum value and a minimum value of average diameters of the columnar bodies taken in planes perpendicular to a thickness direction of the columnar structure film.