SURFACE ACOUSTIC WAVE DEVICE

摘要

PURPOSE:To incorporate a capacitor into a surface acoustic wave device in order to decrease the number of external parts, by providing counter electrodes holding a zinc oxide thin film and over the lead-out electrodes. CONSTITUTION:Counter electrodes 81 and 82 hold a zinc oxide thin film 7 and set on comb-shaped electrodes 61 and 62. While counter electrodes 101 and 102 are provided on lead-out electrodes 91 and 92 respectively. Thus the electrostatic capacity is produced between electrodes 91 and 92 as well as 101 and 102 respectively. Therefore connecting the electrode 101 of the electrode 91 to an input/output terminal 121 is equivalent to capacitors connected in series. Furthermore connecting electrodes 92 and 102 to an input/output terminal 122 and an earth terminal respectively is equal to capacitors connected in parallel. Thus it is possible to incorporate a capacitor into a surface acoustic wave device. This contributes to reduction of the number of external parts.