| 摘要 |
PURPOSE:To enable to obtain very slight delay time versus temperature characteristics with very thin film thickness of oxide film and a large coupling coefficient, by forming the electrode toward specific angle on X-cut LiTaO3 substrate. CONSTITUTION:On an LiTaO3 substrate 11, an input interdigital electrode 12 and an output interdigital electrode 13 are formed toward about 112 deg. from the Y axis for the propagation of elastic surface waves. Further, on the substrate 11 including the electrodes 12 and 13, an si oxideized film 14 is coated with the film thickness of 1/20-1/6 of the elastic surfade wave length propagated. As a result, since excellent delay time versus temperature characteristics and coupling coefficient can be obtained with very thin film thickness of oxidized film, the film can be formed in a very short time. |
