COMPOSITE BOARD AND METHOD FOR MAKING SAME

摘要

A composite board (10) is obtained by joining a piezoelectric board (12) and a support board (14) together by means of a direct joining using an ion beam. One surface of the piezoelectric board (12) is a polarization minus surface (12a), while another surface of the piezoelectric board (12) is a polarization plus surface (12b). The rate of etching using a strong acid for the polarization minus surface (12a) is greater than for the polarization plus surface (12b). The polarization plus surface (12b) of the piezoelectric board (12) is directly joined to the support board (14), while the polarization plus surface (12b) of the piezoelectric board (12) appears on the outside. The polarization minus surface (12a) of the piezoelectric board (12) has been etched by use of the strong acid. The support board (14) is made of a material having a greater rate of etching using the strong acid than the polarization minus surface (12a) of the piezoelectric board (12).