SURFACE ACOUSTIC WAVE ELEMENT

摘要

PURPOSE:To decrease the insertion loss at a high frequency band by forming a piezoelectric layer with a laser abrasion method in a surface acoustic wave element formed by laminating a diamond and the piezoelectric layer. CONSTITUTION:A polycrystal diamond layer 2 is formed onto an Si substrate 1 with the microwave plasma CVD method by using H2 and CH4 as raw material gases, after the surface is polished to form 2 pairs of Al comb-type electrodes 3. A ZnO film 4 is formed from the upper part of the electrode 3 by the laser abrasion method. The ZnO film 4 has not only an excellent C axis orientation but also forms a high resistance film without Li dope with small particle diameter and excellent surface flatness different from a conventional element. The surface acoustic wave element with small surface acoustic wave propagation loss and small insertion loss is realized through the lamination structure comprising the ZnO film 4 and the polycrystal diamond layer 2.