| 摘要 |
<p>An improved surface acoustic wave device in which electrodes composed of a film made of copper-added aluminum alloy are formed on a piezoelectric substrate. In the electrodes of the device, copper segregates near crystal grain boundaries, that is, the concentration of copper existing in the form of atoms not in the form of an intermetallic compound is higher near the boundaries compared with the inside of crystal grains in the aluminum alloy film. The ratio of the concentration of copper near grain boundaries to that in the crystal grains is larger than 1.6. In a more preferable mode, the ratio of the concentration is larger than 2.2. It is preferable that the electrodes on the surface of the piezoelectric substrate are aluminum alloy films to which 0.5-2.0 wt.% copper is added. A method for forming such electrodes on the piezoelectric substrate is also disclosed.</p> |
