A manufacturing method of a piezoelectric element includes: forming a first conductive film on a vibration plate as a substrate; etching a first conductive film; forming a second conductive film on the first conductive film; etching the second conductive film to form a first electrode having a step region as a step formed by the second conductive film and the first conductive film at ends thereof; forming a seed layer as an orientation control layer covering the first electrode by a liquid phase method; forming a piezoelectric film on the seed layer; etching the piezoelectric film to form a piezoelectric body; and forming a second electrode covering the piezoelectric body.

A manufacturing method of a piezoelectric element includes: forming a first conductive film on a vibration plate as a substrate; etching a first conductive film; forming a second conductive film on the first conductive film; etching the second conductive film to form a first electrode having a step region as a step formed by the second conductive film and the first conductive film at ends thereof; forming a seed layer as an orientation control layer covering the first electrode by a liquid phase method; forming a piezoelectric film on the seed layer; etching the piezoelectric film to form a piezoelectric body; and forming a second electrode covering the piezoelectric body.

A piezoelectric element includes a support and a vibration unit disposed on the support. The vibration unit includes a piezoelectric film and an electrode film connected to the piezoelectric film to extract charges generated by deformation of the piezoelectric film. The vibration unit has a support region supported on the support, and a vibration region connected to the support region and floating from the support. The vibration unit outputs a pressure detection signal based on the charges. The vibration region includes a plurality of slits extending from a support region side toward a center of the vibration region and is in a state of being supported at both ends with respect to the support region.

A method of manufacturing a piezoelectric actuator includes preparing a laminate including a substrate, a first electrode layer disposed on the substrate, a piezoelectric layer disposed on the first electrode layer, and a second electrode layer disposed on the piezoelectric layer, and forming a contour shape of the piezoelectric layer. The forming of the contour shape includes dry etching the piezoelectric layer from the second electrode layer side to dig the piezoelectric layer halfway in a thickness direction, covering, with a resist film, a dry etched surface formed on a side surface of the piezoelectric layer by the dry etching, and wet etching the piezoelectric layer from the second electrode layer side to dig the piezoelectric layer until the first electrode layer is reached.

A method of manufacturing a piezoelectric actuator includes preparing a laminate including a substrate, a first electrode layer disposed on the substrate, a piezoelectric layer disposed on the first electrode layer, and a second electrode layer disposed on the piezoelectric layer, and forming a contour shape of the piezoelectric layer. The forming of the contour shape includes dry etching the piezoelectric layer from the second electrode layer side to dig the piezoelectric layer halfway in a thickness direction, covering, with a resist film, a dry etched surface formed on a side surface of the piezoelectric layer by the dry etching, and wet etching the piezoelectric layer from the second electrode layer side to dig the piezoelectric layer until the first electrode layer is reached.

A wafer level ultrasonic device includes a composite layer, a first conductive layer, a second conductive layer, a base, a first electrical connection region, and a second electrical connection region. The composite layer includes an ultrasonic element and a protective layer. The ultrasonic element includes a first electrode and a second electrode. The protective layer has a first connecting channel and a second connecting channel respectively corresponding to the first electrode and the second electrode. The first conductive layer and the second conductive layer are respectively in the first connecting channel and the second connecting channel to connect the first electrode and the second electrode. The base includes an opening forming a closed cavity with the protective layer. The first electrical connection region and the second electrical connection region are respectively filled with metal materials to electrically connect the first conductive layer and the second conductive layer.

A wafer level ultrasonic device includes a composite layer, a first conductive layer, a second conductive layer, a base, a first electrical connection region, and a second electrical connection region. The composite layer includes an ultrasonic element and a protective layer. The ultrasonic element includes a first electrode and a second electrode. The protective layer has a first connecting channel and a second connecting channel respectively corresponding to the first electrode and the second electrode. The first conductive layer and the second conductive layer are respectively in the first connecting channel and the second connecting channel to connect the first electrode and the second electrode. The base includes an opening forming a closed cavity with the protective layer. The first electrical connection region and the second electrical connection region are respectively filled with metal materials to electrically connect the first conductive layer and the second conductive layer.

Piezoelectric devices having small dimensions and which can operate at high frequencies with high penetration depths for a given applied voltage are described. The devices may be well suited for integration into medical devices, such as intravascular ultrasound (IVUS) catheters, to provide high resolution ultrasound images.

A piezoelectric actuator includes a substrate, and a first piezoelectric device and a second piezoelectric device formed at the substrate. The first piezoelectric device includes a first lower electrode, a first piezoelectric body, and a first upper electrode. The second piezoelectric device includes a second lower electrode, a second piezoelectric body, and a second upper electrode. A side surface of the first lower electrode is not covered with the first piezoelectric body, and a side surface of the second lower electrode is not covered with the second piezoelectric body. The piezoelectric actuator further includes a common electrode formed at the substrate and coupled to the first upper electrode and the second upper electrode, and an insulating layer located between the common electrode and the first lower electrode and between the common electrode and the second lower electrode.

A piezoelectric actuator includes a substrate, and a first piezoelectric device and a second piezoelectric device formed at the substrate. The first piezoelectric device includes a first lower electrode, a first piezoelectric body, and a first upper electrode. The second piezoelectric device includes a second lower electrode, a second piezoelectric body, and a second upper electrode. A side surface of the first lower electrode is not covered with the first piezoelectric body, and a side surface of the second lower electrode is not covered with the second piezoelectric body. The piezoelectric actuator further includes a common electrode formed at the substrate and coupled to the first upper electrode and the second upper electrode, and an insulating layer located between the common electrode and the first lower electrode and between the common electrode and the second lower electrode.