| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a thin-film acoustic resonator with high performance superior in electromechanical coupling coefficient and acoustic quality factor or the like. <P>SOLUTION: A pit 52 is formed in a substrate comprising a silicon wafer 51 on a surface of which a silicon oxide thin layer 53 is formed. A sandwich structure 60, comprising a piezoelectric layer 62 and lower and upper electrodes 61, 63 jointed to both surfaces of the piezoelectric layer, is disposed so as to stride over the pit 52. The upper surface of the lower electrode 61 and the lower surface of the piezoelectric layer 62 jointed to the upper surface of the lower electrode are treated so that the RMS variation of the height thereof is equal to 50 nm or smaller. The thickness of the lower electrode 61 is set to 150 nm or smaller. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
