Characteristics of Hybrid SAW/BAW Pressure Sensing Element Based on IDT/ZnO/AlN/Diamond Structure
The acoustic characteristics of hybrid SAW/BAW devices based on IDT/ZnO/AlN/Diamond with layered,etched,and filled structures are investigated using finite element methods.The results indicate that when hZnO/λ=0.3,hAlN/λ=0.5,and the ZnO piezoelectric film is completely etched(d/hZnO=1),a maximum K2 of 6.54% is obtained for the hybrid SAW/BAW(named quasi-Sezawa wave)excited in etched structure,which is nearly two times that of the layered SAW structure(d/hZnO=0).The K2 and pressure sensing properties of the quasi-Sezawa devices are further improved by introducing SiO2 and Diamond fillings.As d/hZnO=1,the pressure frequency shifts of the quasi-Sezawa device with SiO2 and Diamond fillings are 81.2 kHz/MPa and 207.4 kHz/MPa,respectively,which are 58.7% and 300% higher than those of the etched structure.Meanwhile,the frequency pres-sure coefficient(PCF)of the quasi-Sezawa device with Diamond fillings is 297×10-6/MPa,which is approximately 30% higher than that of the layered SAW structure.It can be concluded that different function sensors based on the hybrid SAW/BAW can be developed by introducing different fillings.This can have important application prospects in the fields of pressure,temperature and gas sensing sensors.
NETL
NSTL
万方数据
