| 摘要 |
<p>A surface acoustic wave device with suppressed reduction in frequency characteristics caused by unwanted waves is provided. The surface acoustic wave device (1) comprises a piezoelectric substrate (21), an IDT electrode (22) formed on top of the piezoelectric substrate (21), a first dielectric layer (23), and a second dielectric layer (24). The first dielectric layer (23) is formed on top of the piezoelectric substrate (21). The first dielectric layer (23) comprises silicon oxide. The second dielectric layer (24) is formed on top of the first dielectric layer (23). The second dielectric layer (24) has a faster sonic speed than the first dielectric layer (23). The surface acoustic wave device (1) also comprises a third dielectric layer (25). The third dielectric layer (25) is formed between the first dielectric layer (23) and the piezoelectric substrate (21). The third dielectric layer (25) covers the surface (21a) of the piezoelectric substrate (21), and the upper surface (22a) and the side surfaces (22b, 22c) of the IDT electrode (22).</p> |
