TY - JOUR
T1 - Development of PVDF-TrFE/SiO2 composite film bulk acoustic resonator
AU - Kaneko, Ryosuke
AU - Froemel, Joerg
AU - Tanaka, Shuji
N1 - Funding Information:
This study was supported by the Program for Leading Graduate Schools, ‘Inter-Graduate School Doctoral Degree Program on Global Safety’ of the MEXT, Japan .
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/12/1
Y1 - 2018/12/1
N2 - This paper reports a film bulk acoustic resonator (FBAR) using polyvinylidene fluoride- trifluoroethylene (PVDF-TrFE)/SiO2 composite. The PVDF-TrFE/SiO2 composite FBAR was designed, simulated and developed. A Micro Electro Mechanical Systems (MEMS) process including xenon difluoride (XeF2) release etching was adopted with some tuning for PVDF-TrFE. The influences of the process on the surface morphology and crystal orientation of PVDF-TrFE were evaluated for RIE, gold sputtering and XeF2 etching. After poling PVDF-TrFE, the thickness expansion mode was observed at 387–398 MHz. Impedance characteristics was evaluated using a modified Butterworth-Van Dyke (MBVD) model for a lossy piezoelectric transducer. Impedance ratio, coupling coefficient (k2), mechanical quality factor (Qm) and figure of merit increase with the radius of the device. The maximum Qm is 33 for 80 μm radius of the device. The residual film stress of PVDF-TrFE was estimated as 34.8 MPa in tensile mean stress and −79.7 kPa in gradient stress. Elastic stiffness constants c33 D and c33 E at electrical displacement D = 0 and electric field E = 0 were obtained as 4.45 GPa and 4.46 GPa, respectively.
AB - This paper reports a film bulk acoustic resonator (FBAR) using polyvinylidene fluoride- trifluoroethylene (PVDF-TrFE)/SiO2 composite. The PVDF-TrFE/SiO2 composite FBAR was designed, simulated and developed. A Micro Electro Mechanical Systems (MEMS) process including xenon difluoride (XeF2) release etching was adopted with some tuning for PVDF-TrFE. The influences of the process on the surface morphology and crystal orientation of PVDF-TrFE were evaluated for RIE, gold sputtering and XeF2 etching. After poling PVDF-TrFE, the thickness expansion mode was observed at 387–398 MHz. Impedance characteristics was evaluated using a modified Butterworth-Van Dyke (MBVD) model for a lossy piezoelectric transducer. Impedance ratio, coupling coefficient (k2), mechanical quality factor (Qm) and figure of merit increase with the radius of the device. The maximum Qm is 33 for 80 μm radius of the device. The residual film stress of PVDF-TrFE was estimated as 34.8 MPa in tensile mean stress and −79.7 kPa in gradient stress. Elastic stiffness constants c33 D and c33 E at electrical displacement D = 0 and electric field E = 0 were obtained as 4.45 GPa and 4.46 GPa, respectively.
KW - Film bulk acoustic resonator
KW - MBVD model
KW - PVDF-TrFE/SiO composite
KW - Thickness expansion mode
UR - http://www.scopus.com/inward/record.url?scp=85055153833&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85055153833&partnerID=8YFLogxK
U2 - 10.1016/j.sna.2018.10.025
DO - 10.1016/j.sna.2018.10.025
M3 - Article
AN - SCOPUS:85055153833
VL - 284
SP - 120
EP - 128
JO - Sensors and Actuators A: Physical
JF - Sensors and Actuators A: Physical
SN - 0924-4247
ER -