| 摘要 |
PROBLEM TO BE SOLVED: To obtain an interdigital electrode with a sufficient immunity against stress migration by adopting a single crystal aluminum film for an electrode formed on the surface of a piezoelectric substrate. SOLUTION: Three input IDTs 21, 22, 23 and four output IDTs 24, 25, 26, 27 are arranged alternately on the surface of a piezoelectric substrate 10 made of a lithium tetraborate single crystal (Li2 B4 O7 ) of a (110)-cut (45 deg. rotation cut) and an electrode structural array 20 is formed, in which the input IDTs 21, 22, 23 and the output IDTs 24, 25, 26, 27 are inserted between a couple of reflectors 28, 29. The three input IDTs 21, 22, 23 are connected in parallel with each other and the four output IDTs 24, 25, 26, 27 are connected in parallel with each other. The electrode structural array 20 including the IDTs as above is formed on a single crystal aluminum film 30 on the surface of the piezoelectric substrate 10 in a way that the direction in parallel with the surface is oriented to be the (111)-plane. The film thickness is nearly 100nm. |
