| 摘要 |
PURPOSE:To improve the temperature characteristic of the resonance frequency by coating a dielectric film to the surface of a crystal substrate. CONSTITUTION:The delay time temperature coefficient of the surface acoustic wave element is changed by coating a dielectric film to the surface of the crystal substrate 1 of the surface acoustic wave element having at least a couple of reed screen electrodes 2 on the crystal substrate 1. For example, sputter vapor-deposition of Al is applied onto a 34 deg. rotation Y-cut crystal substrate 1 with a film thickness of 10000Angstrom and the reed screen electrode 2 and the reflector 3 are formed by a wet photo etching method. Then magnetron sputter vapor-deposition of silicon dioxide is applied to the upper side to form the dielectric film 4. Thus, the temperature characteristic of the resonance frequency is improved remarkably and the surface acoustic wave element with good temperature stability is obtained without using a constant temperature oven even at a high frequency such as a UHF band or a GHz band.
|
