PREPARATION AND PIEZOELECTRIC PROPERTY OF LEAD TITANATE THIN-FILMS FOR GHZ-BAND RESONATORS

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.