SURFACE ACOUSTIC WAVE ELEMENT

摘要

PURPOSE:To obtain a high frequency surface acoustic wave element by laminating a piezoelectric thin film and an electrode to at least one face of a plate substrate made of an aluminum nitride sintered body. CONSTITUTION:After the piezoelectric thin film is laminated on the surface of the plate substrate made of an aluminum nitride sintered body, the electrode is provided on the thin film. The mechanically broken-out section of the aluminum nitride sintered body is formed with the dense packing state of minute crystal grains distinguished by clear profile, said clear profile at said broken-out section of the minute crystal grains is polygonal and in defining the average grain diameter at said broken-out section specified by said clear profile in said minute crystal as D(mum), at least 70% of crystal grains having the grain diameter of 0.3D-1.8D preferably 0.5D-1.5D share.