| 摘要 |
PURPOSE:To obtain high electric-mechanical coupling coefficient and excellent group delay time temperature characteristics, by piling SiO2 including phosphor on the surface acoustic wave substrate with chemical vapor piling method. CONSTITUTION:On the surface acoustic wave substrate 1 providing the interdigital electrode 3, SiO2 4 is piled and formed, including phosphor with chemical vapor piling method. The pile of SiO2 4 is formed, for example, by mixing a trace of phosphine to silane and producing phosphor silicate glass PSG and water through thermo chemical reaction with oxygen. The PSG is in itself fine in the construction and smooth on the surface, allowing to obtain excellent surface characteristics and performance simply. Further, the temperature characteristics of the group delay time given to the board 1 and those given to the SiO2 4 in phosphor doping can be mutually cancelled to increase the group delay time temperature characteristics. |
