Piezoelectric PZT thin-film transformers with a ring–dot structure

Abstract

In this study, we present the design, the modeling, the fabrication, and the characterization of ring–dot type piezoelectric thin-film transformers (PTFTs). The structure of the PTFTs was a simple circular plate of Pb(Zr,Ti)O3 (PZT) thin film on a Si layer with ring–dot top electrodes and it was suspended by four pantograph-shaped bridges. We estimated the performance of the PTFTs by finite-element method simulations. In accordance with the FEM simulation model, PZT thin films were deposited on silicon-on-insulator substrates and microfabricated into PTFTs with ring–dot structures. From the produced devices, an admittance circle measurement was carried out, enabling us to predict performance. The actual output characteristics of the PTFTs were clearly observed at a resonance frequency (f r) of 4.57 MHz. At this point, a voltage gain of 0.22 and a power density of 704 W cm−3 were measured, under a load resistance (R L) of 22 Ω.

Structural Design and Physical Mechanism of Axial and Radial Sandwich Resonators with Piezoelectric Ceramics: A Review

“…Piezoelectric ceramic sensors play an important role in the measurement of detonations caused by the mismatch of combustion pressure, vacuum, and ignition angle in automobile engine. Another common application of piezoelectric ceramics is the type of ceramic transformers illustrated in Figure 5 [ 69 , 70 , 71 ], which is smaller in volume and lighter in weight than traditional instruments. Their efficiency can reach 60~80%.…”

Origin of Ferroelectricity in BiFeO3-Based Solid Solutions

“…Ferroelectric tetragonal PbTiO 3 forms a solid solution with antiferroelectric rhombohedral PbZrO 3 [ 2 , 3 ]. Their dielectric and piezoelectric properties are maximal at around the morphotropic phase boundary (MPB) [ 4 ], and the properties around the MPB have been widely utilized for sensors, ultrasonic motors, and medical transducers [ 5 , 6 , 7 ]. Single crystals of Pb(Mg, Nb)O 3 –PbTiO 3 and Pb(Zn, Nb)O 3 –PbTiO 3 exhibit extraordinary high electromechanical coupling factors because a bridging phase in monoclinic symmetry [ 4 , 8 , 9 , 10 ] is capable of a rotation of P s under electric fields [ 8 , 11 , 12 , 13 , 14 ].…”

Ferroelectric polarization of tetragonal BiFeO3—an approach from DFT calculations for BiFeO3–BaTiO3 superlattices—

“…Because of its superior properties, PZT has been widely used for various applications such as sensors, ultrasonic motors and transducers. [4][5][6][7][8][9] For Pb(Mg, Nb)O 3 -PbTiO 3 and Pb(Zn, Nb)O 3 -PbTiO 3 with extraordinary high piezoelectric properties, their MPBs provide a bridging phase in monoclinic symmetry 3,[10][11][12] that enables a rotation of the spontaneous polarization (P s ) vector. 10,[13][14][15][16][17][18][19][20][21][22] To establish an MBP similar to the PZT system, various lead-free solid solution systems have been investigated and composition-driven variations of crystal structure and properties have been studied.…”