Abstract: A microelectromechanical mirror device has, in a die of semiconductor material: a fixed structure defining a cavity; a tiltable structure carrying a reflecting region elastically suspended above the cavity; at least a first pair of driving arms coupled to the tiltable structure and carrying respective piezoelectric material regions which may be biased to cause a rotation thereof around at least one rotation axis; elastic suspension elements coupling the tiltable structure elastically to the fixed structure and which are stiff with respect to movements out of the horizontal plane and yielding with respect to torsion; and a piezoresistive sensor configured to provide a detection signal indicative of the rotation of the tiltable structure. At least one test structure is integrated in the die to provide a calibration signal indicative of a sensitivity variation of the piezoresistive sensor in order to calibrate the detection signal.

Abstract: A process for manufacturing a microelectromechanical mirror device includes, in a semiconductor wafer, defining a support frame, a plate connected to the support frame so as to be orientable around at least one rotation axis, and cantilever structures extending from the support frame and coupled to the plate so that bending of the cantilever structures causes rotations of the plate around the at least one rotation axis. The process further includes forming piezoelectric actuators on the cantilever structures, forming pads on the support frame, and forming spacer structures protruding from the support frame more than both the pads and the stacks of layers forming the piezoelectric actuators.

Abstract: A microelectromechanical mirror device includes a fixed structure defining a cavity, a tiltable structure elastically suspended above the cavity and carrying a reflecting surface, and having a main extension in a horizontal plane. A first pair of driving arms carry respective piezoelectric material regions that are biased to cause a rotation of the tiltable structure around a first rotation axis parallel to a first horizontal axis of the horizontal plane, and elastically coupled to the tiltable structure. Elastic suspension elements that couple the tiltable structure to the fixed structure at the first rotation axis are stiff with respect to movements out of the horizontal plane and yielding with respect to torsion around the first rotation axis, and further extend between the tiltable structure and the fixed structure. The elastic suspension elements have an asymmetrical arrangement on opposite sides of the tiltable structure along the first rotation axis.

Abstract: A MEMS device includes a semiconductor body with a cavity and forming an anchor portion, a tiltable structure elastically suspended over the cavity, first and second support arms to support the tiltable structure, and first and second piezoelectric actuation structures biasable to deform mechanically, generating a rotation of the tiltable structure around a rotation axis. The piezoelectric actuation structures carry first and second piezoelectric displacement sensors. When the tiltable structure rotates around the rotation axis, the displacement sensors are subject to respective mechanical deformations and generate respective sensing signals in phase opposition to each other, indicative of the rotation of the tiltable structure. The sensing signals are configured to be acquired in a differential manner.

Abstract: A micromechanical device includes a fixed structure, a mobile portion rotatable about a first rotation axis, and a first actuation structure arranged between the fixed structure and the mobile portion to enable rotation of the mobile portion about the first rotation axis. The mobile portion includes a supporting structure, a tiltable platform rotatable about a second rotation axis, transverse to the first rotation axis, and a second actuation structure coupled between the tiltable platform and the supporting structure. Stiffening elements are arranged between the supporting structure and the fixed structure. The micromechanical device may be used within a pico-projector.

Abstract: Disclosed herein is a method of making a microelectromechanical (MEMS) device. The method includes, in a single structural layer, affixing a tiltable structure to an anchorage portion with first and second supporting arms extending between the anchorage portion and opposite sides of the tiltable structure, and forming first and second resonant piezoelectric actuation structures extending between a constraint portion of the first supporting arm and the anchorage portion, on opposite sides of the first supporting arm. The method further includes coupling a handling wafer underneath the structural layer to define a cavity therebetween, and forming a passivation layer over the structural layer, the passivation layer having contact openings defined therein for routing metal regions for electrical coupling to respective electrical contact pads, the electrical contact pads being electrically connected to the first and second resonant piezoelectric actuation structures.

Abstract: A microelectromechanical mirror device has a fixed structure defining a cavity. A tiltable structure carrying a reflecting surface is elastically suspended above the cavity with a main extension in a horizontal plane. Elastic elements are coupled to the tiltable structure and at least one first pair of driving arms, which carry respective regions of piezoelectric material, are biasable to cause rotation of the tiltable structure about at least one first axis of rotation parallel to a first horizontal axis of the horizontal plane. The driving arms are elastically coupled to the tiltable structure on opposite sides of the first axis of rotation and are interposed between the tiltable structure and the fixed structure. The driving arms have a thickness, along an orthogonal axis transverse to the horizontal plane, smaller than a thickness of at least some of the elastic elements coupled to the tiltable structure.

Abstract: A MEMS device is formed in a die of semiconductor material having a cavity defined therein and having an anchorage portion. A tiltable structure is elastically suspended over the cavity and has a main extension in a horizontal plane. First and second supporting arms extend between the anchorage portion and opposite sides of the tiltable structure. First and second resonant piezoelectric actuation structures are intended to be biased to thereby cause rotation of the tiltable structure about a rotation axis. The first supporting arm is formed by first and second torsion springs, which are rigid to movements out of the horizontal plane and compliant to torsion about the rotation axis and are coupled together at a constraint region. The first and second resonant piezoelectric actuation structures extend between the anchorage portion and the constraint structure, on first and second sides of the first supporting arm.

Abstract: A MEMS device is formed by a body of semiconductor material which defines a support structure. A pass-through cavity in the body is surrounded by the support structure. A movable structure is suspended in the pass-through cavity. An elastic structure extends in the pass-through cavity between the support structure and the movable structure. The elastic structure has a first and second portions and is subject, in use, to mechanical stress. The MEMS device is further formed by a metal region, which extends on the first portion of the elastic structure, and by a buried cavity in the elastic structure. The buried cavity extends between the first and the second portions of the elastic structure.

Abstract: A microelectromechanical device includes a fixed structure having a frame defining a cavity, a tiltable structure elastically suspended above the cavity with main extension in a horizontal plane, a piezoelectrically driven actuation structure which can be biased to cause a desired rotation of the tiltable structure about a first and second rotation axes, and a supporting structure integral with the fixed structure and extending in the cavity starting from the frame. Lever elements are elastically coupled to the tiltable structure at a first end by elastic suspension elements and to the supporting structure at a second end by elastic connecting elements which define a lever rotation axis. The lever elements are elastically coupled to the actuation structure so that their biasing causes the desired rotation of the tiltable structure about the first and second rotation axes.

Abstract: A microelectromechanical mirror device includes a supporting frame of semiconductor material and a plate of semiconductor material. The plate is connected to the supporting frame so as to be orientable around at least one rotation axis. A reflective layer is arranged on a first region of the plate. A piezoelectric actuation structure extends on a second region of the plate adjacent to the reflective layer. The piezoelectric actuation structure is configured to apply forces such as to modify a curvature of the plate.

Abstract: A MEMS micromirror device is formed in a package including a containment body and a lid transparent to a light radiation. The package forms a cavity housing a tiltable platform having a reflecting surface. A metastructure is formed on the lid and/or on the reflecting surface and includes a plurality of diffractive optical elements.

Abstract: The MEMS actuator is formed by a substrate, which surrounds a cavity; by a deformable structure suspended on the cavity; by an actuation structure formed by a first piezoelectric region of a first piezoelectric material, supported by the deformable structure and configured to cause a deformation of the deformable structure; and by a detection structure formed by a second piezoelectric region of a second piezoelectric material, supported by the deformable structure and configured to detect the deformation of the deformable structure.

Abstract: A microelectromechanical device includes a body of semiconductor material, which forms a cavity, a mobile structure, and an actuation structure. The actuation structure includes at least one first deformable element which faces the cavity and is mechanically coupled to the body and to the mobile structure, and a piezoelectric-actuation system which can be controlled so as to deform the first deformable element and cause a consequent rotation of the mobile structure. The mobile structure includes a supporting region and at least one first pillar region, the first pillar region being mechanically coupled to the first deformable element, the supporting region being set on the first pillar region and overlying at least part of the first deformable element.

Abstract: To manufacture an oscillating structure, a wafer is processed by: forming torsional elastic elements; forming a mobile element connected to the torsional elastic elements; processing the first side of the wafer to form a mechanical reinforcement structure; and processing the second side of said wafer by steps of chemical etching, deposition of metal material, and/or deposition of piezoelectric material. Processing of the first side of the wafer is carried out prior to processing of the second side of the wafer so as not to damage possible sensitive structures formed on the first side of the wafer.

Abstract: A micro-electro-mechanical device is formed by a fixed structure having a cavity. A tiltable structure is elastically suspended over the cavity and has a main extension in a tiltable plane and is rotatable about a rotation axis parallel to the tiltable plane. A piezoelectric actuation structure includes first and second driving arms carrying respective piezoelectric material regions and extending on opposite sides of the rotation axis. The first and the second driving arms are rigidly coupled to the fixed structure and are elastically coupled to the tiltable structure. During operation, a stop structure limits movements of the tiltable structure with respect to the actuation structure along a planar direction perpendicular to the rotation axis. The stop structure has a first planar stop element formed between the first driving arm and the tiltable structure and a second planar stop element formed between the second driving arm and the tiltable structure.

Abstract: For manufacturing an optical microelectromechanical device, a first wafer of semiconductor material having a first surface and a second surface is machined to form a suspended mirror structure, a fixed structure surrounding the suspended mirror structure, elastic supporting elements which extend between the fixed structure and the suspended mirror structure, and an actuation structure coupled to the suspended mirror structure. A second wafer is machined separately to form a chamber delimited by a bottom wall having a through opening. The second wafer is bonded to the first surface of the first wafer in such a way that the chamber overlies the actuation structure and the through opening is aligned to the suspended mirror structure. Furthermore, a third wafer is bonded to the second surface of the first wafer to form a composite wafer device. The composite wafer device is then diced to form an optical microelectromechanical device.

Abstract: A microelectromechanical mirror device has a fixed structure defining a cavity. A tiltable structure carrying a reflecting surface is elastically suspended above the cavity with a main extension in a horizontal plane. Elastic elements are coupled to the tiltable structure and at least one first pair of driving arms, which carry respective regions of piezoelectric material, are biasable to cause rotation of the tiltable structure about at least one first axis of rotation parallel to a first horizontal axis of the horizontal plane. The driving arms are elastically coupled to the tiltable structure on opposite sides of the first axis of rotation and are interposed between the tiltable structure and the fixed structure. The driving arms have a thickness, along an orthogonal axis transverse to the horizontal plane, smaller than a thickness of at least some of the elastic elements coupled to the tiltable structure.

Abstract: A MEMS device is formed in a die of semiconductor material having a cavity defined therein and having an anchorage portion. A tiltable structure is elastically suspended over the cavity and has a main extension in a horizontal plane. First and second supporting arms extend between the anchorage portion and opposite sides of the tiltable structure. First and second resonant piezoelectric actuation structures are intended to be biased to thereby cause rotation of the tiltable structure about a rotation axis. The first supporting arm is formed by first and second torsion springs, which are rigid to movements out of the horizontal plane and compliant to torsion about the rotation axis and are coupled together at a constraint region. The first and second resonant piezoelectric actuation structures extend between the anchorage portion and the constraint structure, on first and second sides of the first supporting arm.

Abstract: A microelectromechanical structure includes a body of semiconductor material having a fixed frame internally defining a cavity, a mobile mass elastically suspended in the cavity and movable with a first resonant movement about a first rotation axis and with a second resonant movement about a second rotation axis, orthogonal to the first axis. First and second pairs of supporting elements, extending in cantilever fashion in the cavity, are rigidly coupled to the frame, and are piezoelectrically deformable to cause rotation of the mobile mass about the first and second rotation axes. First and second pairs of elastic-coupling elements are elastically coupled between the mobile mass and the first and the second pairs of supporting elements. The first and second movements of rotation of the mobile mass are decoupled from one another and do not interfere with one another due to the elastic-coupling elements of the first and second pairs.