| 摘要 |
PROBLEM TO BE SOLVED: To provide a proper substrate for a surface acoustic wave device which does not have problem as to crack and/or warp generation by paying attention to the thickness of microcrack layer. SOLUTION: The substrate for the surface acoustic wave device consists of a single crystal of lithium tantalate and has an excitation electrode for generating a surface acoustic wave formed on one main surface thereof. Arithmetic mean roughness (Ra) of the other main surface 1 is 0.2-0.3 μm, and a micro- crack layer is not thicker than 1 μm from the lower surface in the other surface. |
