METHOD FOR MANUFACTURING PIEZOELECTRIC BULK ACOUSTIC WAVE ELEMENT AND PIEZOELECTRIC BULK ACOUSTIC WAVE ELEMENT

摘要

A method for manufacturing a piezoelectric bulk acoustic wave element by forming a sacrificial layer on a part of a primary surface of a substrate. A piezoelectric film sandwiched between a pair of electrodes is formed on the primary surface of the substrate so as to cover the sacrificial layer, the piezoelectric film being formed from scandium-containing aluminum nitride having a scandium atomic concentration with respect to the total number of scandium atoms and aluminum atoms of more than 24 atomic percent. An etching step of removing the sacrificial layer by etching is performed. Prior to the etching step, a protective film formed from aluminum nitride or scandium-containing aluminum nitride having a lower scandium atomic concentration than that of the piezoelectric film is provided so as to cover at least a part of a portion of the piezoelectric film located in a region in which the sacrificial layer is provided.

主权项

1. A method for manufacturing a piezoelectric bulk acoustic wave element, the method comprising:
forming a sacrificial layer on a part of a primary surface of a substrate; forming a piezoelectric film between a pair of electrodes on the primary surface of the substrate so as to cover the sacrificial layer, the piezoelectric film being formed from scandium-containing aluminum nitride having a scandium atom concentration with respect to a total number of scandium atoms and aluminum atoms of more than 24 atomic percent; forming a protective film so as to cover at least a part of a portion of the piezoelectric film located in a region in which the sacrificial layer is provided, the protective film being formed from aluminum nitride or scandium-containing aluminum nitride having a lower scandium atomic concentration than that of the piezoelectric film; and after the forming of the protective film, removing the sacrificial layer by etching.