| 摘要 |
PROBLEM TO BE SOLVED: To attain a surface acoustic wave device having excellent temperature characteristics and a sufficient electromechanical coupling coefficient. SOLUTION: A surface acoustic wave device 1 has: a sapphire substrate 10 having a C plane as a main surface; an aluminum nitride film 30 which is formed on a main surface 11 of the sapphire substrate 10; comb-like electrodes 21, 22 which are formed on the surface of the aluminum nitride film 30 to excite surface acoustic waves; and a silicon dioxide film 40 which covers the comb-like electrodes 21, 22 and the surface of the aluminum nitride film 30. The surface acoustic waves use a secondary mode of Sezawa waves. The relationship between a standardized film thickness KH-AIN of the aluminum nitride film 30 and a standardized film thickness KH-SiO<SB>2</SB>of the silicon dioxide film 40 is set to an appropriate range, and thereby the surface acoustic wave device 1 having excellent temperature characteristics, a sufficient electromechanical coupling coefficient K<SP>2</SP>required for excitation, and a high sonic velocity is provided. COPYRIGHT: (C)2011,JPO&INPIT
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