Various embodiments of the present disclosure are directed towards a method for forming a piezoelectric device including a piezoelectric membrane and a plurality of conductive layers. The method includes forming the plurality of conductive layers in the piezoelectric membrane, the plurality of conductive layers are vertically offset one another. A masking layer is formed over the piezoelectric membrane. An etch process is performed according to the masking layer to concurrently expose an upper surface of each conductive layer in the plurality of conductive layers. A plurality of conductive vias are formed over the upper surface of the plurality of conductive layers.

The invention provides a planarization method, which can make the local flatness of the product to be processed more uniform. The product has a cavity filled with oxide and includes a first electrode layer, a piezoelectric layer and a second electrode layer superposed on the cavity. The first electrode layer covers the cavity and includes a first inclined face around the first electrode layer, and the piezoelectric layer covers the first electrode layer and is arranged on the first electrode layer. The planarization method includes: depositing a passivation layer on the second electrode layer and etching the passivation layer completely until the thickness of the passivation layer is reduced to the required thickness.

A process for producing a piezoelectric sensor includes the following steps: a step of providing a housing made of stainless steel; a step of producing a solution of a compound comprising a metal or metalloid element; a step of depositing a layer of the solution over at least one inner surface of the housing; a step of oxidizing the deposited layer of solution; a step of placing a piezoelectric element inside the housing; a step of closing the housing. A piezoelectric sensor obtained by such a process and comprising a closed steel housing, a piezoelectric element arranged inside the housing and a layer of a solution of a compound comprising a metal or metalloid element that is arranged over at least one inner surface of the housing.

A process for producing a piezoelectric sensor includes the following steps: a step of providing a housing made of stainless steel; a step of producing a solution of a compound comprising a metal or metalloid element; a step of depositing a layer of the solution over at least one inner surface of the housing; a step of oxidizing the deposited layer of solution; a step of placing a piezoelectric element inside the housing; a step of closing the housing. A piezoelectric sensor obtained by such a process and comprising a closed steel housing, a piezoelectric element arranged inside the housing and a layer of a solution of a compound comprising a metal or metalloid element that is arranged over at least one inner surface of the housing.

A design process is used for designing a device comprising a plurality of micro-machined elements, each comprising a flexible membrane, the elements being arranged in a plane in a determined topology. The design process comprises a step of defining the determined topology so that it has a character compatible with a generic substrate having cavities, the characteristics of which are pre-established. Each flexible membrane of the micro-machined elements is associated with one cavity of the generic substrate. The present disclosure also relates to a fabrication process for fabricating a device comprising a plurality of micro-machined elements, and to this device itself, wherein only some of the pairs of cavities and flexible membranes are configured to form a set of functional micro-machined elements.

A process for fabricating a micro-electro-mechanical system, includes the following steps: production of a stack on the surface of a temporary substrate so as to produce a first assembly, comprising: at least depositing a piezoelectric material or a ferroelectric material to produce a layer of piezoelectric material or of ferroelectric material; producing a first bonding layer; production of a second assembly comprising at least producing a second bonding layer on the surface of a host substrate; production of at least one acoustic isolation structure in at least one of the two assemblies; production of at least one electrode level containing one or more electrodes in at least one of the two assemblies; bonding the two assemblies via the two bonding layers, before or after the production of the at least one electrode level in at least one of the two assemblies; removing the temporary substrate.

A movable piezo element and to a method for producing the element are provided. The movable piezo element may have a structured substrate, in which an intermediate layer is arranged between a first substrate layer and a second substrate layer. The element may also have a first electrode layer. The element may also have a second electrode layer arranged on the ferroelectric, piezoelectric, or flexoelectric layer. The second substrate layer may be structured such that at least one bar of the second substrate layer is formed. The bar may be clamped on one side and may be physically spaced from the first substrate layer. A surface of the bar facing away from the first substrate layer, and/or a lateral surface of the bar, may be at least partly covered by another layer.

In one embodiment, a transducer comprises a first piezoelectric stack comprising a piezoelectric material; a first layer in contact with the piezoelectric stack; and a base structure beneath the first layer. The first layer has a first displacement between a first portion of the base structure and the first layer, and the first displacement is configurable by a first bias voltage received by the transducer.

A MEMS device having a body with a first and a second surface, a first portion and a second portion. The MEMS device further has a cavity extending in the body from the second surface; a deformable portion between the first surface and the cavity; and a piezoelectric actuator arranged on the first surface, on the deformable portion. The deformable portion has a first region with a first thickness and a second region with a second thickness greater than the first thickness. The second region is adjacent to the first region and to the first portion of the body.

In accordance with some embodiments, a method of forming an auto-focusing device is provided. The method includes forming a cantilever beam member. The cantilever beam member has a ring shape. The method further includes forming a piezoelectric member over the cantilever beam member. The method also includes forming a membrane over the cantilever beam member. The membrane has a first region and a second region. The first region has a planar surface, and the second region is located between the first region and an inner edge of the cantilever beam member and has a plurality of corrugation structures. In addition, the method includes applying a liquid optical medium over the membrane and sealing the liquid optical medium with a protection layer.