| 摘要 |
PURPOSE:To improve the reflecting characteristics, by forming a vapor-deposited film made of metal not oxidized than aluminum on one major plane of a piezoelectric substrate, an aluminum vapor-deposited film further on it, and further exciting electrodes and reflecting electrodes. CONSTITUTION:After forming a vapor-deposited film such as nickel or chromium hardly oxidized than high purity aluminum on one major plane of a piezoelectric substrate 11, a high purity aluminum vapor-deposited film is formed on this vapor-deposited film, and exciting electrodes 12 and reflection electrodes 13 and 14 are formed on the two-layered vapor-deposited film by means of photoetching method. Thus, the metal in contacting with the piezoelectric substrate 11 is made of a nickel or chromium layer 16 which is hardly oxidized, and since an oxide 161 of this layer 16 is very less and an oxide 181 of an aluminum layer 18 on the layer 16 is much, the shape of reflecting elements 131 and 141 including oxides 181 and 161 is a cross section of a house with an eaves Further, since a layer 17 is well processed with an etching liquid, an end in contacting with the piezoelectric substrate 11 is almost at a right angle, allowing to improve the reflecting characteristics equivalently. |
