Multi-layered thin film piezoelectric devices and methods of making the same

摘要

Multi-layered thin film piezoelectric material stacks and devices incorporating such stacks. In embodiments, an intervening material layer is disposed between two successive piezoelectric material layers in at least a portion of the area of a substrate over which the multi-layered piezoelectric material stack is disposed. The intervening material may serve one or more function within the stack including, but not limited to, inducing an electric field across one or both of the successive piezoelectric material layers, inducing a discontinuity in the microstructure between the two successive piezoelectric materials, modulating a cumulative stress of the piezoelectric material stack, and serving as a basis for varying the strength of an electric field as a function of location over the substrate.

主权项

1. A thin film piezoelectric device, comprising:
a piezoelectric element including:
a lower electrode disposed over a first region of a substrate;a first piezoelectric layer having a first polarization disposed over the lower electrode;a second piezoelectric layer having the first polarization disposed over the first piezoelectric layer;an intervening layer disposed between the first and second piezoelectric layers in at least a portion of the first region, wherein the intervening layer is of a different composition than that of the first and second piezoelectric layers; andan upper electrode disposed over the second piezoelectric layer;wherein the piezoelectric element is in fluid communication with a pumping chamber, or wherein the piezoelectric element is disposed over a sealed cavity of an ultrasonic transducer.