Abstract: A bottom semiconductor region is formed to include a main sub-region, extending through a bottom dielectric region that coats a semiconductor wafer, and a secondary sub-region which coats the bottom dielectric region and surrounds the main sub-region. First and second top cavities are formed through the wafer, delimiting a fixed body and a patterned structure that includes a central portion which contacts the main sub-region, and deformable portions in contact with the bottom dielectric region. A bottom cavity is formed through the bottom semiconductor region, as far as the bottom dielectric region, the bottom cavity laterally delimiting a stiffening region including the main sub-region and leaving exposed parts of the bottom dielectric region that contact the deformable portions and parts of the bottom dielectric region that delimit the first and second top cavities. The parts left exposed by the bottom cavity are selectively removed.

Abstract: A piezoelectric transducer includes a semiconductor body with a bottom electrode of conductive material. A piezoelectric element is on the bottom electrode. A first protective layer, on the bottom electrode and the piezoelectric element, has a first opening through which a portion of the piezoelectric element is exposed, and a second opening through which a portion of the bottom electrode is exposed. A conductive layer on the first protective layer and within the first and second openings is patterned to form a top electrode in electrical contact with the piezoelectric element at the first opening, a first biasing stripe in electrical contact with the top electrode, and a second biasing stripe in electrical contact with the bottom electrode at the second opening.

Abstract: A piezoelectric microelectromechanical structure is provided with a piezoelectric stack having a main extension in a horizontal plane and a variable section in a plane transverse to the horizontal plane. The stack is formed by a bottom-electrode region, a piezoelectric material region arranged on the bottom-electrode region, and a top-electrode region arranged on the piezoelectric material region. The piezoelectric material region has, as a result of the variable section, a first thickness along a vertical axis transverse to the horizontal plane at a first area, and a second thickness along the same vertical axis at a second area. The second thickness is smaller than the first thickness. The structure at the first and second areas can form piezoelectric detector and a piezoelectric actuator, respectively.

Abstract: A piezoelectric transducer includes a semiconductor body with a bottom electrode of conductive material. A piezoelectric element is on the bottom electrode. A first protective layer, on the bottom electrode and the piezoelectric element, has a first opening through which a portion of the piezoelectric element is exposed, and a second opening through which a portion of the bottom electrode is exposed. A conductive layer on the first protective layer and within the first and second openings is patterned to form a top electrode in electrical contact with the piezoelectric element at the first opening, a first biasing stripe in electrical contact with the top electrode, and a second biasing stripe in electrical contact with the bottom electrode at the second opening.

Abstract: A bottom semiconductor region is formed to include a main sub-region, extending through a bottom dielectric region that coats a semiconductor wafer, and a secondary sub-region which coats the bottom dielectric region and surrounds the main sub-region. First and second top cavities are formed through the wafer, delimiting a fixed body and a patterned structure that includes a central portion which contacts the main sub-region, and deformable portions in contact with the bottom dielectric region. A bottom cavity is formed through the bottom semiconductor region, as far as the bottom dielectric region, the bottom cavity laterally delimiting a stiffening region including the main sub-region and leaving exposed parts of the bottom dielectric region that contact the deformable portions and parts of the bottom dielectric region that delimit the first and second top cavities. The parts left exposed by the bottom cavity are selectively removed.