Design considerations for tunable bulk acoustic wave resonators based on paraelectric phase BaxSr1-xTiO3 thin films

• Paraelectric phase BaxSr1-xTiO3 (BSTO) is due to the pronounced field induced piezoelectric effect a promising candidate to realize hysteresis-free tunable thin film bulk acoustic wave resonators (TFBARs) at GHz frequencies. Compared to the conventional fixed-frequency TFBAR technology, mainly based on piezoelectric AlN films, the design of tunable BSTO based resonators require additional considerations due to the demanding conditions necessary for the growth of the BSTO active layer (high temperature, O2 ambient). In this work a number of problems and possible solutions are presented for the specific case of solidly mounted resonators based on an acoustic Bragg reflector structure. Simulation results for a proposed tunable resonator based on a BSTO film and a SiO2/HfO2 reflector stack co-optimized for both longitudinal and shear waves are presented and compared to simulations and existing experimental data from other structures.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Annan materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Other Materials Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Annan elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Other Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

Keyword

resonator

microwave

acoustic

ferroelectric

Publication and Content Type

kon (subject category)

vet (subject category)