| 摘要 |
PROBLEM TO BE SOLVED: To provide a substrate for surface acoustic wave devices that can reduce the grain size of a piezoelectric thin film after film formation by decreasing roughness on a surface for forming the piezoelectric thin film, can obtain a precise alignment layer having high crystallinity, is superior in high-frequency characteristics, and has a high degree of freedom in electric characteristics and temperature ones. SOLUTION: The substrate for surface acoustic wave devices comprises a silicon substrate 101, a dielectric thin film 102 formed on the silicon substrate 101, and a piezoelectric thin film 103 formed on the dielectric thin film 102. In this case, surface roughness at the side of the piezoelectric thin film 103 of the dielectric thin film 102 is set to 2.0nm or smaller in Ra, thus manufacturing the substrate for surface acoustic wave devices that can be used even at a high frequency, such as 1-5 GHz and has a high degree of freedom in electric characteristics and temperature ones. COPYRIGHT: (C)2005,JPO&NCIPI
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