A transducer includes a first piezoelectric layer; and a second piezoelectric layer that is above the first piezoelectric layer; wherein the second piezoelectric layer is a more compressive layer with an average stress that is less than or more compressive than an average stress of the first piezoelectric layer.

A method for manufacturing a MEMS device is disclosed. Moreover a MEMS device and a module including a MEMS device are disclosed. An embodiment includes a method for manufacturing MEMS devices includes forming a MEMS stack on a first main surface of a substrate, forming a polymer layer on a second main surface of the substrate and forming a first opening in the polymer layer and the substrate such that the first opening abuts the MEMS stack.

A method of forming a Micro-Electro-Mechanical System (MEMS) includes forming a lower electrode on a first insulator layer within a cavity of the MEMS. The method further includes forming an upper electrode over another insulator material on top of the lower electrode which is at least partially in contact with the lower electrode. The forming of the lower electrode and the upper electrode includes adjusting a metal volume of the lower electrode and the upper electrode to modify beam bending.

A method of forming a Micro-Electro-Mechanical System (MEMS) includes forming a lower electrode on a first insulator layer within a cavity of the MEMS. The method further includes forming an upper electrode over another insulator material on top of the lower electrode which is at least partially in contact with the lower electrode. The forming of the lower electrode and the upper electrode includes adjusting a metal volume of the lower electrode and the upper electrode to modify beam bending.

A method of forming a Micro-Electro-Mechanical System (MEMS) includes forming a lower electrode on a first insulator layer within a cavity of the MEMS. The method further includes forming an upper electrode over another insulator material on top of the lower electrode which is at least partially in contact with the lower electrode. The forming of the lower electrode and the upper electrode includes adjusting a metal volume of the lower electrode and the upper electrode to modify beam bending.

A method of forming a Micro-Electro-Mechanical System (MEMS) includes forming a lower electrode on a first insulator layer within a cavity of the MEMS. The method further includes forming an upper electrode over another insulator material on top of the lower electrode which is at least partially in contact with the lower electrode. The forming of the lower electrode and the upper electrode includes adjusting a metal volume of the lower electrode and the upper electrode to modify beam bending.

A method of forming at least one Micro-Electro-Mechanical System (MEMS) includes patterning a wiring layer to form at least one fixed plate and forming a sacrificial material on the wiring layer. The method further includes forming an insulator layer of one or more films over the at least one fixed plate and exposed portions of an underlying substrate to prevent formation of a reaction product between the wiring layer and a sacrificial material. The method further includes forming at least one MEMS beam that is moveable over the at least one fixed plate. The method further includes venting or stripping of the sacrificial material to form at least a first cavity.

A method of forming at least one Micro-Electro-Mechanical System (MEMS) includes forming a beam structure and an electrode on an insulator layer, remote from the beam structure. The method further includes forming at least one sacrificial layer over the beam structure, and remote from the electrode. The method further includes forming a lid structure over the at least one sacrificial layer and the electrode. The method further includes providing simultaneously a vent hole through the lid structure to expose the sacrificial layer and to form a partial via over the electrode. The method further includes venting the sacrificial layer to form a cavity. The method further includes sealing the vent hole with material. The method further includes forming a final via in the lid structure to the electrode, through the partial via.

A method of forming at least one Micro-Electro-Mechanical System (MEMS) includes forming a beam structure and an electrode on an insulator layer, remote from the beam structure. The method further includes forming at least one sacrificial layer over the beam structure, and remote from the electrode. The method further includes forming a lid structure over the at least one sacrificial layer and the electrode. The method further includes providing simultaneously a vent hole through the lid structure to expose the sacrificial layer and to form a partial via over the electrode. The method further includes venting the sacrificial layer to form a cavity. The method further includes sealing the vent hole with material. The method further includes forming a final via in the lid structure to the electrode, through the partial via.

Method for encapsulating a microelectronic device, comprising the following steps: producing a sacrificial portion covering the device; producing a cover covering the sacrificial portion, comprising two superimposed layers of separate materials and having different residual stresses and/or coefficients of thermal expansion; etching, through the cover, of a trench of which the pattern comprises a curve and/or two straight non-parallel segments; etching of the sacrificial portion through the trench; depositing a sealing material on the trench; in which, during the etching of the sacrificial portion, a portion of the cover defined by the trench deforms under the effect of a mechanical stress generated by the residual stresses and/or a thermal expansion of the layers of the cover and increases the dimensions of the trench, this stress being eliminated before the sealing of the trench.