Film bulk acoustic wave resonators (FBAWRs) at the GHz band were succe
ssfully fabricated using piezoelectric lead titanate, PbTiO3 (PT) film
s on GaAs substrates by a process similar to that used in microwave in
tegrated circuit (MIG) fabrication. PT films deposited on Pt/Ti bottom
electrodes by RF magnetron sputtering oriented preferentially dong th
e [111] crystal direction. Resonances of the bulk acoustic mode were o
bserved around 1.9 GHz. The effective electromechanical coupling coeff
icient (k(t)(2)) and electrical Q were estimated to be similar to 9.4%
and similar to 65, respectively. The relationship between residual st
ress in the PT films and Q was investigated. It was found that stress
in the PT film exerted a large influence on Q.