SURFACE ACOUSTIC WAVE DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a surface acoustic wave device the delay time temperature coefficient of which is reduced. SOLUTION: Single crystal piezoelectric substrates employing the same type of material are joined by taking a propagation direction of a surface acoustic wave in parallel with the direction in which the linear expansion coefficient is small in order to improve the linear expansion coefficient. Or the joining layer of a joined substrate obtained by joining substrates made of different kinds of materials employs a coated glass layer with a high heat resistance and ease of handling.