STUDY ON POWER DURABILITY OF TI-CONTAINING AL SURFACE-ACOUSTIC-WAVE ELECTRODES, USING INTERDIGITATED INTERDIGITAL TRANSDUCER FILTERS

The power durability of Al-0.6 wt% Ti electrodes in 900 MHz interdigitated interdigital transducer surface acoustic wave (IIDT SAW) filters was investigated through accelerated time-to-failure (TF) tests in relation to grain sizes and annealing, and was further compared with that of pure Al, Al-0.5 wt% Pd and conventional Al-1.1 wt% Cu electrodes. TF of the Al-0.6 wt% Ti electrodes in the IIDT filter is increased by reducing the average grain size and the standard deviation of the grain size. Annealing of Al-0.6 wt% Ti film, however, results in increase of the average grain size and decrease of TF. TF of Al-0.6 wt% Ti electrodes was the largest: much larger than that of Al-0.5 wt% Pd electrodes, having almost the same grain size and standard deviation as Al-0.6 wt% Ti electrodes, and nine times as large as that of Al-1.1 wt% Cu electrodes.