Title :
Micromachined thin film bulk acoustic resonators
Author :
Ruby, R. ; Merchant, P.
Author_Institution :
Hewlett-Packard Labs., Palo Alto, CA, USA
Abstract :
We have fabricated thin film bulk acoustic resonators (FBARS) with measured Q´s of over 1000 and resonant frequencies as low as 1.5 GHz and as high as 7.5 GHz. The device, as currently fabricated, consists of the piezoelectric material aluminum nitride (AlN) sandwiched between electrodes all of which lie on a thin low-stress silicon nitride (SixNy) membrane. Integrated on the membrane are small microheaters for frequency tuning and/or temperature stabilization. We have observed frequency shifts of 50 to 80 ppm per degree C depending on relative material thicknesses. Maximum temperature excursions over 580 C could be achieved using the microheaters. We have also observed frequency shifts of 5 to 10 ppm per volt depending on harmonic
Keywords :
Q-factor; acoustic microwave devices; acoustic resonators; aluminium compounds; bulk acoustic wave devices; membranes; micromachining; micromechanical resonators; silicon compounds; thin film devices; tuning; 1.5 GHz; 580 C; 7.5 GHz; AlN; SiN; frequency shifts; frequency tuning; microheaters; micromachined thin film bulk acoustic resonators; piezoelectric material; relative material thicknesses; resonant frequencies; temperature stabilization; thin low-stress SixNy membrane; Acoustic devices; Acoustic measurements; Biomembranes; Film bulk acoustic resonators; Frequency measurement; Piezoelectric films; Piezoelectric materials; Resonant frequency; Temperature; Transistors;
Conference_Titel :
Frequency Control Symposium, 1994. 48th., Proceedings of the 1994 IEEE International
Conference_Location :
Boston, MA
Print_ISBN :
0-7803-1945-1
DOI :
10.1109/FREQ.1994.398344
